review remaining reserves at deep mines the department trade and

Comments

Transcription

review remaining reserves at deep mines the department trade and
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
A
REVIEW
OF THE
REMAINING RESERVES
AT DEEP MINES
FOR
THE DEPARTMENT
OF
TRADE AND INDUSTRY
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table of Contents
1
EXECUTIVE SUMMARY ..............................................................................................1
1.1 Introduction ....................................................................................................................1
1.2 Geology and Reserves ....................................................................................................2
1.2.1
Definition of the Reserves Assessment ..................................................................2
1.2.2
Change in Position..................................................................................................2
1.2.3
IMC’s Interpretation ...............................................................................................3
1.2.4
Final Reserves and Resources Statement (IMC) as at December 2002 .................4
1.3 Longer Term Investment ................................................................................................4
1.3.1
UK Coal plc mines .................................................................................................5
1.3.2
Other Individual Mines...........................................................................................7
1.4 Conclusions ....................................................................................................................9
2
Terms of Reference.........................................................................................................12
2.1 Study Framework .........................................................................................................12
2.1.1
Data Acquisition ...................................................................................................12
2.2 Methodology.................................................................................................................15
3
2.2.1
Part 1.....................................................................................................................15
2.2.2
Part II ....................................................................................................................15
2.2.3
Part III...................................................................................................................17
BACKGROUND.............................................................................................................20
3.1 Overview of market ......................................................................................................20
3.2 Import competition .......................................................................................................20
3.3 Import prices.................................................................................................................20
3.4 Implication for delivered price of UK coal ..................................................................21
3.5 Costs, prices and viability.............................................................................................21
3.6 Recent developments in the Power Generation Sector.................................................21
3.7 Other Issues ..................................................................................................................22
3.8 Financial Overview for Investment ..............................................................................24
4
Assessment of Existing Deep Mines for Future Investment .......................................25
4.1 General Introduction.....................................................................................................25
4.1.1
General Reporting.................................................................................................25
4.1.2
Evaluation of Reserves and Resources .................................................................25
4.1.3
Exploration and Re-categorisation of Reserves....................................................25
4.1.4
Opportunities for Further Investment ...................................................................27
4.2 Clipstone Colliery.........................................................................................................29
4.2.1
I5104C
Brief description of Site........................................................................................29
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.2.2
Mine Boundaries, Other Surface Constraints and Issues .....................................29
4.2.3
Geological Assessment.........................................................................................29
4.2.4
Mine Characteristics and Constraints ...................................................................37
4.2.5
Historic Performance............................................................................................38
4.2.6
Future Mining Projection......................................................................................39
4.2.7
Production and Development Forecasts ...............................................................39
4.2.8
Opportunities for Further Investment ...................................................................39
4.3 Daw Mill Colliery.........................................................................................................40
4.3.1
Brief description of Site........................................................................................40
4.3.2
Mine Boundaries, Other Surface Constraints and Issues .....................................40
4.3.3
Geological Assessment of the Mine .....................................................................40
4.3.4
Mine Characteristics and Constraints ...................................................................47
4.3.5
Historic Performance............................................................................................49
4.3.6
Future mining projection ......................................................................................50
4.3.7
Production and Development Forecasts ...............................................................50
4.3.8
Opportunities for Further Investment ...................................................................53
4.4 Ellington Colliery .........................................................................................................56
4.4.1
Brief Description of Site.......................................................................................56
4.4.2
Mine boundaries, other surface constraints and issues.........................................56
4.4.3
Geological Assessment of the Mine .....................................................................56
4.4.4
Mine characteristics and constraints.....................................................................66
4.4.5
Historic Performance............................................................................................68
4.4.6
Production and Development Forecasts ...............................................................69
4.4.7
Opportunities for Further Investment ...................................................................70
4.5 Harworth Colliery.........................................................................................................72
4.5.1
Brief description of Site........................................................................................72
4.5.2
Mine boundaries, Other Surface Constraints and Issues ......................................72
4.5.3
Geological Assessment of the Mine .....................................................................72
4.5.4
Mine characteristics and constraints.....................................................................80
4.5.5
Historic Performance............................................................................................83
4.5.6
Production and Development Forecasts ...............................................................84
4.5.7
Opportunities for Further Investment ...................................................................87
4.6 Kellingley Colliery .......................................................................................................89
4.6.1
Brief description of Site........................................................................................89
4.6.2
Mine Boundaries, Other Surface Constraints and Issues .....................................89
4.6.3
Geological Assessment of the Mine .....................................................................89
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.6.4
Mine characteristics and constraints...................................................................100
4.6.5
Historic Performance..........................................................................................103
4.6.6
Production and Development Forecasts .............................................................104
4.6.7
Opportunities for Further Investment .................................................................106
4.7 Maltby Colliery...........................................................................................................108
4.7.1
Brief description of Site......................................................................................108
4.7.2
Mine Boundaries, Other Surface Constraints and Issues ...................................108
4.7.3
Geological Assessment of the Mine ...................................................................108
4.7.4
Mine Characteristics and Constraints .................................................................116
4.7.5
Historic Performance..........................................................................................119
4.7.6
Future Mining Projection....................................................................................120
4.7.7
Production and Development Forecasts .............................................................121
4.7.8
Opportunities for Further Investment .................................................................124
4.8 Rossington Colliery ....................................................................................................125
4.8.1
Brief Description of Site.....................................................................................125
4.8.2
Mine Boundaries, Other Surface Constraints and Issues ...................................125
4.8.3
Geological Assessment of the Mine ...................................................................125
4.8.4
Mine Characteristics and Constraints .................................................................132
4.8.5
Historic Performance..........................................................................................135
4.8.6
Future Mining Projection....................................................................................136
4.8.7
Production and Development Forecasts .............................................................136
4.8.8
Opportunities for Further Investment .................................................................138
4.9 Thoresby Colliery .......................................................................................................139
4.9.1
Brief Description of Site.....................................................................................139
4.9.2
Mine Boundaries, Other Surface Constraints and Issues ...................................139
4.9.3
Geological Assessment of the Mine ...................................................................139
4.9.4
Mine Characteristics and Constraints .................................................................148
4.9.5
Historic Performance..........................................................................................150
4.9.6
Future Mining Projection....................................................................................151
4.9.7
Production and Development Forecasts .............................................................151
4.9.8
Opportunities for Further Investment .................................................................153
4.10
Welbeck Colliery....................................................................................................155
4.10.1 Brief description of Site......................................................................................155
4.10.2 Mine boundaries .................................................................................................155
4.10.3 Geological Assessment of the Mine ...................................................................155
4.10.4 Mine Characteristics and Constraints .................................................................163
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.10.5 Historic Performance..........................................................................................165
4.10.6 Future Mining Projection....................................................................................166
4.10.7 Production and Development Forecasts .............................................................166
4.10.8 Opportunities for Further Investment .................................................................169
4.11
Hatfield Colliery .....................................................................................................171
4.11.1 Brief description of Site......................................................................................171
4.11.2 Mine Boundaries, Other Surface Constraints and Issues ...................................171
4.11.3 Geological Assessment of the Mine ...................................................................171
4.11.4 Mine Characteristics and Constraints .................................................................181
4.11.5 Historic Performance..........................................................................................185
4.11.6 Future mining projection ....................................................................................185
4.11.7 Production and Development Forecasts .............................................................186
4.11.8 Opportunities for Further Investment .................................................................187
4.12
Thorne Colliery.......................................................................................................189
4.12.1 Brief Description of Site.....................................................................................189
4.12.2 Mine Boundaries, Other Surface Constraints and Issues ...................................189
4.12.3 Geological Assessment of the Mine ...................................................................189
4.12.4 Exploration .........................................................................................................191
4.12.5 Other Seams of Interest ......................................................................................191
4.12.6 IMC Commentary on the Reserve/Resource for Thorne Colliery......................191
4.12.7 Mine Characteristics and Constraints .................................................................194
4.13
Tower Colliery........................................................................................................196
4.13.1 Brief Description of Site.....................................................................................196
4.13.2 Mine Boundaries, Other Surface Constraints and Issues ...................................196
4.13.3 Geological Assessment of the Mine ...................................................................196
4.13.4 Mine Characteristics and Constraints .................................................................203
4.13.5 Historic Performance..........................................................................................206
4.13.6 Future Mining Projection....................................................................................206
4.13.7 Production and Development Forecasts .............................................................206
4.13.8 Opportunities for Further Investment .................................................................208
4.14
Aberpergwm Colliery .............................................................................................215
4.14.1 Brief Description of Site.....................................................................................215
4.14.2 Mine Boundaries, Other Surface Constraints and Issues ...................................215
4.14.3 Geological Assessment of the Mine ...................................................................215
4.14.4 Mine Characteristics and Constraints .................................................................223
4.14.5 Historic Performance..........................................................................................225
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.14.6 Future Mining Projection....................................................................................226
4.14.7 Production and Development Forecasts .............................................................226
4.14.8 Opportunities for Further Investment .................................................................228
4.15
Betws Colliery ........................................................................................................234
4.15.1 Brief Description of Site.....................................................................................234
4.15.2 Mine Boundaries, Other Surface Constraints and Issues ...................................234
4.15.3 Geological Assessment of the Mine ...................................................................234
4.15.4 Structure and Landslips ......................................................................................234
4.15.5 Mine Characteristics and Constraints .................................................................239
4.15.6 Historic Performance..........................................................................................242
4.15.7 Future Mining Projection....................................................................................242
4.15.8 Production and Development Forecasts .............................................................242
4.15.9 Opportunities for Further Investment .................................................................244
4.16
Eckington Colliery..................................................................................................251
4.16.1 Brief Description of Site.....................................................................................251
4.16.2 Mine Boundaries, Other Surface Constraints and Issues ...................................251
4.16.3 Geological Assessment of the Mine ...................................................................251
4.16.4 Mine Characteristics and Constraints .................................................................255
4.16.5 Historic Performance..........................................................................................257
4.16.6 Future Mining Projection....................................................................................257
4.16.7 Production and Development Forecasts .............................................................258
4.16.8 Opportunities for Further Investment .................................................................259
4.17
Hayroyds Colliery...................................................................................................263
4.17.1 Brief Description of Site.....................................................................................263
4.17.2 Mine Boundaries, Other Surface Constraints and Issues ...................................263
4.17.3 Geological Assessment of the Mine ...................................................................263
4.17.4 Mine Characteristics and Constraints .................................................................267
4.17.5 Historic Performance..........................................................................................269
4.17.6 Future Mining Projection....................................................................................270
4.17.7 Production and Development Forecasts .............................................................270
4.17.8 Opportunities for Further Investment .................................................................271
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
List of Tables
Table 1-1
Final Reserves and Resources Statement (IMC) as at December 2002 .................4
Table 4-1
Clipstone: Reserve/Resource Summary January 1998 (Source: UK Coal plc)....32
Table 4-2 Clipstone: Reserve/Resource Summary January 2000 & July 2002 (Source: UK
Coal plc) ...........................................................................................................................32
Table 4-3
Clipstone Colliery: Reserves and Resources Comparison ...................................33
Table 4-4
IMC Re-assessment of Clipstone Reserve/Resource Summary: (01/12/02) ........37
Table 4-5
Historical Production Performance at Clipstone ..................................................38
Table 4-6
Historical Development Performance at Clipstone ..............................................39
Table 4-7
Daw Mill Colliery Reserve/Resource Summary (01/07/98) (Source: RJB Mining)
42
Table 4-8
plc)
Daw Mill Colliery Reserve/Resource Summary (July 2002) (Source: UK Coal
42
Table 4-9
Daw Mill Colliery Reserves and Resources Comparison ....................................44
Table 4-10 IMC Reassessment of Daw Mill Reserve/Resource Summary (01/12/02) ..........47
Table 4-11 Historical Production Performance at Daw Mill ..................................................49
Table 4-12 Historical Development Performance at Daw Mill ..............................................50
Table 4-13 Five-Year schedule ...............................................................................................51
Table 4-14 Ellington Colliery Reserve/Resource Summary (01/07/98) (Source: RJB Mining)
59
Table 4-15 Ellington Colliery Reserve/Resource Summary (July 2002) (Source: UK Coal
plc) 59
Table 4-16 Ellington Colliery Reserves and Resources Comparison .....................................60
Table 4-17 IMC Re-assessment of Ellington Colliery Reserve/Resource (Dec 2002)...........66
Table 4-18 Historical Production Performance at Ellington...................................................68
Table 4-19 Historical Development Performance at Ellington...............................................68
Table 4-20 Harworth Colliery Reserve/Resource Summary (01/07/98) (Source: RJB Mining)
74
Table 4-21 Harworth Colliery Reserve/Resource Summary (01/07/02) (Source: RJB Mining)
74
Table 4-22 Harworth Colliery Reserves and Resources Comparison.....................................76
Table 4-23 IMC Re-assessment of Harworth Colliery Reserve/Resource (Dec 2002) ..........80
Table 4-24 Historical Production Performance at Harworth ..................................................83
Table 4-25 Historical Development Performance at Harworth ..............................................83
Table 4-26 Draft Five-Year Schedule.....................................................................................85
Table 4-27 Kellingley Reserve/Resource Summary (01/07/98) (Source: RJB Mining) ........92
Table 4-28 Kellingley Reserve/Resource Summary (01/07/02) (Source: UK Coal)..............92
Table 4-29 Kellingley Reserves and Resources Comparison .................................................94
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table 4-30 IMC Reassessment of Kellingley Reserve/Resource Summary (01/07/02).........99
Table 4-31 Historical Production Performance at Kellingley...............................................103
Table 4-32 Historical Development Performance at Kellingley...........................................103
Table 4-33 Draft Five Year Production Schedule.................................................................104
Table 4-34 Maltby: Reserve/Resource Summary January 1998 (Source: RJB Mining) ......110
Table 4-35 Maltby: Reserve/Resource Summary July 2002 (Source: UK Coal) .................110
Table 4-36 Maltby: Reserves and Resources Comparison ...................................................112
Table 4-37 IMC Reassessment of Maltby Reserve/Resource Summary (01/07/02) ............116
Table 4-38 IMC Reassessment of the Maltby Reserve/Resource Summary (01/12/02) ......116
Table 4-39 Historical Production Performance at Maltby ....................................................119
Table 4-40 Historical Development Performance at Maltby ................................................119
Table 4-41 Production Schedule for Two Face Strategy ......................................................121
Table 4-42 Production Schedule for Transition to Single Face Production .........................122
Table 4-43 Production Schedule to the Cessation of Production..........................................123
Table 4-44 Rossington Reserve/Resource Summary (01/07/98) (Source: RJB Mining) .....127
Table 4-45 Rossington Reserve/Resource Summary (01/07/02) (Source: UK Coal)...........128
Table 4-46 Rossington Reserves and Resources Comparison ..............................................129
Table 4-47 IMC Summary Reassessment of the Rossington Reserve/Resource (01/12/02) 132
Table 4-48 Historical Production Performance at Rossington..............................................135
Table 4-49 Historical Development Performance at Rossington..........................................135
Table 4-50 Draft Five Year Production Schedule.................................................................136
Table 4-51 Thoresby Reserve/Resource Summary (01/07/98) (Source: RJB Mining) ........141
Table 4-52 Thoresby Reserve/Resource Summary (July 2002) (Source: UK Coal) ............142
Table 4-53 Thoresby Reserves and Resources Comparison.................................................143
Table 4-54 Summary of IMC Reassessment of the Thoresby Reserve/Resource (01/12/02)
148
Table 4-55 Historical Production Performance at Thoresby.................................................150
Table 4-56 Historical Development Performance at Thoresby.............................................151
Table 4-57 Draft Five-Year Schedule...................................................................................152
Table 4-58 Welbeck Reserve/Resource Summary (01/07/98) (Source: RJB Mining) .........157
Table 4-59 Welbeck Reserve/Resource Summary (July 2002) (Source: UK Coal) .............157
Table 4-60 Welbeck Reserves and Resources Comparison..................................................159
Table 4-61 IMC Summary Re-assessment of the Welbeck Reserve/Resource (01/12/02) ..163
Table 4-62 Historical Production Performance at Welbeck .................................................165
Table 4-63 Historical Development Performance at Welbeck .............................................166
Table 4-64 Draft Five-Year Schedule...................................................................................167
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table 4-65 Hatfield Reserve/Resource Summary (01/07/98) (Source: Hatfield Coal
Company) .......................................................................................................................174
Table 4-66 Hatfield Barnsley Seam Reserve/Resource Summary (01/05/01)......................175
Table 4-67 Hatfield Reserve/Resource Summary (16/12/02)...............................................180
Table 4-68 Historical Production Performance at Hatfield ..................................................185
Table 4-69 Draft Five Year Production Schedule for High Hazels ......................................186
Table 4-70 Thorne Reserve/Resource Summary (01/07/98) (Source: Hatfield Coal Company)
191
Table 4-71 IMC Reassessment of Thorne Reserve/Resource Summary: (01/12/02) ...........191
Table 4-72 IMC Re-assessment of Tower Reserve/ Resource: Summary (01/12/02)..........203
Table 4-73 Historical Production Performance at Tower .....................................................206
Table 4-74 IMC Re-assessment of Aberpergwm Reserve/Resource: Summary (01/12/02) 222
Table 4-75 Historical Production Performance at Aberpergwm ..........................................225
Table 4-76 IMC Summary Re-assessment of Betws Reserve/Resource: (01/12/02) ...........239
Table 4-77 Historical Production Performance at Betws......................................................242
Table 4-78 IMC Re-assessment of Eckington Reserve/Resource: Summary (01/12/02).....255
Table 4-79 Historical Production Performance at Eckington ...............................................257
Table 4-80 IMC Re-assessment of Hayroyds Reserve/Resource: Summary (01/12/02)......267
Table 4-81 Historical Production Performance at Hayroyds ................................................269
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table of Figures
Figure 4-1 Location of Existing Deep Mines .........................................................................26
Figure 4-2 Clipstone Colliery Yard Seam Plans ....................................................................34
Figure 4-3 Clipstone Colliery: Blackshale Seam Plans..........................................................35
Figure 4-4 Daw Mill Colliery Warwickshire Thick Seam Plan .............................................45
Figure 4-5 Ellington Colliery Main Seam “F” Plan ...............................................................61
Figure 4-6 Ellington Colliery Yard Seam “G” Plan...............................................................62
Figure 4-7 Ellington Colliery Brass Thill Seam “K” Plan .....................................................63
Figure 4-8 Harworth Colliery: Deep Soft Seam Plan.............................................................77
Figure 4-9 Harworth Colliery: Top Hard Seam Plan .............................................................78
Figure 4-10 Kellingley Colliery: Silkstone Seam Plan ............................................................96
Figure 4-11 Kellingley Colliery: Beeston Seam Plan ..............................................................97
Figure 4-12 Kellingley Colliery: Warren House Seam Plan ....................................................98
Figure 4-13 Maltby Colliery: Parkgate Seam Plan ................................................................113
Figure 4-14 Maltby Colliery: Thorncliffe Seam Plan ............................................................114
Figure 4-15 Rossington Colliery: Barnsley Seam Plan..........................................................130
Figure 4-16 Thoresby Colliery: Parkgate Seam Plan.............................................................144
Figure 4-17 Thoresby Colliery: Deep Soft Seam Plan...........................................................145
Figure 4-18 Thoresby Colliery: High Hazles Seam Plan .......................................................146
Figure 4-19 Welbeck Colliery: Parkgate Seam Plan..............................................................160
Figure 4-20 Welbeck Colliery: Deep Soft Seam Plan............................................................161
Figure 4-21 Hatfield Colliery Barnsley Seam Resource Zones May 2001............................176
Figure 4-22 Hatfield Colliery: High Hazel Seam Plan...........................................................178
Figure 4-23 Hatfield Colliery: Barnsley Seam Plan...............................................................179
Figure 4-24 Thorne Colliery: High Hazel Seam Plan ............................................................192
Figure 4-25 Thorne Colliery: Barnsley Seam Plan ................................................................193
Figure 4-26 Tower Colliery: Six Feet Seam Plan ..................................................................209
Figure 4-27 Tower Colliery: Nine Feet Seam Plan................................................................210
Figure 4-28 Tower Colliery: Seven Feet/Five Feet Seam Plan..............................................211
Figure 4-29 Aberpergwm Colliery: Six Feet and Nine Feet Seam Plan ................................229
Figure 4-30 Betws Colliery: Four Feet Seam Plan.................................................................245
Figure 4-31 Betws Colliery: Four Feet Seam Plan.................................................................246
Figure 4-32 Betws Colliery: Upper Nine Feet (Big) Seam Plan............................................247
Figure 4-33 Eckington Colliery: Flockton Seam Plan ..........................................................260
Figure 4-34 Hayroyds Colliery: Whinmoor Seam Plan .........................................................272
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
1
EXECUTIVE SUMMARY
1.1
INTRODUCTION
PAGE 1
This draft report has been prepared by IMC Group Consulting Limited (IMC) in fulfilment of
the requirements of the Study of coal reserves at existing deep mines in the UK awarded by
the Department of Trade and Industry (DTI) on Monday 4th November 2002. The work has
been completed in accordance with the Terms of Reference set out by the DTI and with the
approach and methodology detailed in the IMC proposal submitted on the 24th October 2002.
IMC would like to place on record their thanks to the senior representatives of the mining
companies and the staff at all the mine sites for their kind co-operation and courtesy without
which it would not have been possible to prepare this report to the detail and time scale
required.
The main purpose of this report is to assist the DTI in making an objective assessment of
which of the relevant coal reserves at the remaining deep mines within the UK can be
considered potentially viable. The main aim being to assist in establishing where any future
investment aid scheme may be appropriately directed to maintain commercially viable coal
operations. This is against the backdrop of the ending of the Operating Aid Scheme and the
continuing difficulties that the industry has been facing mainly due to depressed international
coal prices, the situation having recently been exacerbated by the turmoil within the electricity
supply industry.
To fulfil the objectives of the report three main elements have been addressed:
(i)
A geological evaluation including a full assessment of all the reserves at the mine,
including, where appropriate, those adjacent too but outside current licences and
planning consent boundaries.
(ii)
A mining evaluation including a brief assessment of the current situation, future plans
and the suitability of the mine infrastructure for supporting further development.
(iii)
An economic evaluation including the likely commercial viability of accessing and
exploiting future reserves.
To assist in accomplishing the above IMC have undertaken visits to all the mine sites and
conducted underground inspections targeted at the areas where the mine operators believe
there is potential for long term development and attraction for assistance in investment. The
following mines having been examined and reviewed:
Clipstone
Aberpergwm
Daw Mill
Betws
Ellington
Eckington
Harworth
Hatfield (including Thorne reserves)
Kellingley
Hayroyds
Maltby
Tower
Rossington
Thoresby
Welbeck
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
1.2
PAGE 2
GEOLOGY AND RESERVES
The geology and reserves at each of the deep mines in the study has been examined in detail.
The following summary is the culmination of this examination of the various zones at each of
the collieries. This has been done with the view of the present position of the Industry
regarding the viability of the coal and the abandonment of areas that have been lost or had
access denied due to the present production strategy employed.
The changes in the reserves available to the Industry since the last review by IMC in 1998
have been examined and tabulated wherever possible. The conclusions drawn from these
changes are summarised below.
1.2.1
DEFINITION OF THE RESERVES ASSESSMENT
As the majority of the collieries in the review are under UK Coal plc, being the main operator,
the methods of reserve assessment used by that company has been taken as the basis for the
assessment at all mines in the study.
The Reserves Assessment used in this study is based on the guidelines proposed by the
Institution of Mining and Metallurgy (IMM) in 1991 and subsequently incorporated into the
listing regulations of the London Stock Exchange.
All reserves are stated as being ‘mineable coal reserves’ and are based on in-situ coal sections
and takes into account mining and geological losses but not the effects of processing. The
statement also includes an indication of the perceived geological risk associated with the
reserve zones or sub zones.
Reserve/resource zones are based on the tectonic structure of the lease/licence area with
individual zone boundaries being major geological features, lease/licence or planning consent
boundaries. Where significant variation in the seam section (e.g. a major split line) occurs
within a reserve zone, the zone can be divided into sub zones with their own identification
that also makes reference to the full zone identification.
The geological risk is also accounted for in the assessments made by UK Coal plc. An
assessment of the likely geological losses (e.g. from washouts, steep gradients, faulting, seam
splits) is made based on the intensity and quality of proving of the tectonic and sedimentary
environment of the seam. In the assessments, each reserve zone or sub-zone is assigned a
tectonic and a sedimentary risk factor. These risk factors are assigned a reduction (relaxation)
expressed as a percentage, and the total reduction, being the sum of the tectonic and
sedimentary risk factors is applied to in-situ tonnage to give a recoverable tonnage (relaxed
tonnage).
The definitions of reserves and resources are given in Appendix 1. IMC have used these
definitions as the basis for any new assessment at mines without formal reserve statements.
However IMC have examined these reserves and resources in the light of the current mining
situations at the mines and have, in some cases, suggested alternative categorisations. These
are based on the intent to mine these reserves/resources or in the opinion of IMC are areas of
coal where the mining risk is too high. In this respect, IMC have attempted to be realistic
about the reserve assessments. IMC also accept that with future development and exploration
the reserve assessment will change.
1.2.2
CHANGE IN POSITION
The last review in 1998 showed the position of the industry at that time. Since then collieries
have closed and others have worked the reserves available to them. The generation of
workable or mineable reserves at these mines is dynamic and depends upon the degree of
knowledge available at the time of the assessment. The comparison taken with the present is
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 3
in effect an inventory of the mine’s positions with regard to workable coal and is an indication
of how much coal has been generated into the reserves categories due to the exploration of the
zones either by working or by other methods.
This change in tonnages and categories is detailed in the main body of the report and the
differences for these changes are outlined.
1.2.3
IMC’S INTERPRETATION
IMC have attempted to be as realistic as possible with regard to the present day mining
positions at each of the collieries. In any reassessment of the situations concerning mineable
reserves the current mining situation has been examined along with the degree of geological
knowledge of the reserve zones indicated in the statements for each colliery.
In the case of mines under the control of UK Coal plc, the reserve/resource zones have been
assessed in strict accordance with the guidelines proposed by the IMM and in this respect are
determined correctly.
However there are some situations where these guidelines indicate a specific category for the
zone or zones but where in reality these zones have been abandoned or have been determined
by the company as being unworkable under the current economic conditions. IMC have
looked at these zones in the light of the current situation and in some cases reassessed the
categories due to specific reasons. These are given in the individual IMC commentaries in
Section 4 for all the mines.
The collieries worked by the other operators excluding UK Coal plc, in most cases, did not
have formal reserve statements and for these collieries IMC have used the Guidelines laid out
by the IMM to show realistic reserves and resources with regard to the current situations at
the mines. In most of these cases, particularly for the small mines, this is the first formal
assessment that has been completed for many years, whilst mines in UK Coal plc are updated
every twelve months.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
1.2.4
PAGE 4
FINAL RESERVES AND RESOURCES STATEMENT (IMC) AS AT DECEMBER 2002
The current situation with regard to Reserves and Resources is summarised in the table below.
Individual assessments for each of the mines are given in the text in Section 4.
Table 1-1
Final Reserves and Resources Statement (IMC) as at December 2002
Million Tonnes
Colliery
Reserve
Clipstone
0.300
Daw Mill
26.023
Ellington
3.234
Harworth
3.327
Kellingley
Resource
Total
Mineral Potential
0.300
2.400
32.404
43.128
3.234
0.274
3.190
6.517
33.547
8.644
26.148
34.792
22.293
Maltby
5.000
6.300
11.300
12.200
Rossington
3.169
7.982
11.151
6.542
Thoresby
6.398
10.359
16.757
10.255
Welbeck
5.730
2.721
8.451
18.055
Hatfield
0.675
9.491
10.166
19.500
Tower
2.600
6.300
8.900
19.000
Aberpergwm
0.480
3.800
4.280
Betws
0.570
1.400
1.970
Eckington
0.28
0.29
0.57
Hayroyds
0.18
0.05
0.23
6.381
Thorne
Totals
75.332
66.610
84.412
151.022
262.526
Note: This total excludes an estimated 156Mt of mineral potential identified by UK Coal plc for the Witham
Prospect which is outside the existing remit of IMC.
1.3
LONGER TERM INVESTMENT
Generally the majority of the larger mines have investment programmes. In the main this is
confined to replacement or additional equipment that is necessary to fulfil the short and
medium term operational plans. Other than for strategic development drivages at Kellingley
there are no schemes currently in progress that are directly associated with the accessing of
new reserves.
From discussions it is apparent that there is a unanimous view that financial institutions are
risk averse to mining. Operators are also finding it more difficult to secure long-term sales
contracts to substantiate applications for financial assistance for investment. It is therefore
considered doubtful that, should investment aid be confined to 30% of the total cost of the
project by EU Regulations, the remainder could be funded from elsewhere other from within
the company’s own resources. The viability of the short-term mine plans is therefore
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 5
paramount. In many instances, particularly at the smaller operations there is no collateral to
offer as security against loans.
However, the operators have put forward a selection of schemes that could potentially qualify
and be undertaken with the assistance of investment aid. The projects have only been offered
in outline with ‘ball park’ budgets and need to be developed in detail to truly ascertain their
viability. The following is a resume of the potential schemes by colliery. It is anticipated that
as with any major capital investment each individual scheme will be fully evaluated and
tested for financial viability by the Owner / Operators before seeking to make the expenditure.
Similarly, the DTI will test any application for aid to ensure viability and satisfactory
payback. The collieries are presented below alphabetically commencing with the UK Coal plc
mines and their order does not reflect any preference of schemes.
1.3.1
1.3.1.1
UK COAL PLC MINES
Clipstone
UK Coal plc intends to cease operations at the mine in Mid March and return the lease/licence
back to The Coal Authority on the 31st March 2003. No investment proposals have therefore
been put forward for this mine.
1.3.1.2
Daw Mill
Daw Mill has one of the largest reserve bases of any working mine in the UK (26.023Mt
reserve and 6.381Mt resource) and provided that the current difficulties experienced on 301’s
face can be overcome must be considered for potential investment. The following schemes
have been suggested:
• Exploration work in the form of 3D seismic surveys and surface boreholes
•
An integral part of the mine plan is the procurement of a second set of 5m-extraction face
equipment to avoid production gaps and maximise output
•
Upgrading the drift coal clearance system from 800t/h to 1,200t/h by the installation of
new gearboxes and variable speed motors
•
Improvement to man-riding and hence Machine Availability Time by the introduction of
free steered vehicle ‘buses’.
•
Bunkerage improvements and stocking ground increase.
In addition the westerly extension of the main lateral roadways could be capitalised as longlife strategic developments.
For the longer-term it is recognised that, for Daw Mill to exploit the mineral potential
(estimated to be 43.128Mt) south of the current working area, the sinking of a satellite shaft
from the surface would be necessary to provide ventilation and man and materials access. UK
Coal plc has confirmed the potential for a project for a shaft and associated infrastructure
(both surface and underground) and that cost would probably be in the order of £110M.
However, as at this time no formal project has been prepared or financially evaluated and it
may be difficult to obtain planning permission and complete the physical works in time to
ensure continuity of production following exhaustion of the current working area. The
expenditure must also be weighed against the volume of identified mineral potential.
1.3.1.3
Ellington
With limited reserves (3.234Mt)and a poor financial history it would be difficult to
substantiate capital investment at this mine and no investment proposals have been put
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 6
forward. However, UK Coal plc may invest in limited short-term requirements for face
equipment etc.
1.3.1.4
Harworth
The future of the mine relies upon the successful outcome of the exploration programme that
is currently being undertaken to prove 30’ s Area. If the area is workable it will only have
limited life (1.263Mt Reserve and 1.967Mt Resource) and it would be doubtful whether it
could support any major capital investment.
UK Coal plc had been considering the development of a major project to access and work the
Top Hard seam to the north east of 30’ s Area. Recent proving by surface borehole would
indicate the area contains only 13.97Mt of indicated resource. The area is remote and access
would require substantial cross-measure drivages from the current Deep Soft infrastructure.
UK Coal plc has concluded that in the current situation the limited resource of Top Hard
Seam available does not support or justify the cost of investment required to complete such a
major scheme. IMC concur with this view.
1.3.1.5
Kellingley
As in the case of Daw Mill colliery, Kellingley has substantial reserves base (8.644Mt
Reserve, 26.148Mt Resource) and as such has a potential foundation for future investment.
Areas of coal are also available south of the present southern licence boundary
As part of the mine’ s investment programme major developments are ongoing in the Whitley
area of the mine. Further investment in the form of extensions south and east to access both
Silkstone and Beeston seams will be necessary to extend production beyond the five-year
period although five-year plans have still not been finalised. Further projects could emanate
from this expansion of the mine infrastructure. The locomotive system will require extension
with the possibility of up-grading to high-speed and mineral conveyors will require
installation. In addition the change in the geological structure with the need to negotiate
steeper seam gradients and faulting may require the installation of alternative supply systems
with transhipment stations from the locomotives. Additional booster fans may also be
necessary to maintain ventilation. It is possible that the roadway development and
aforementioned associated work could be prepared and considered as a single major project.
Immediate improvements to the coal preparation facilities are being undertaken to overcome
the imbalance in capacity to that of the mine. However, it is possible that further investment
may be needed in the plant.
UK Coal plc has alluded to a potential long-term scheme to access and work the Warren
House seam. IMC estimate that some 18.148Mt of mineral potential is available in a seam
that has only limited thickness. As such a major scheme would be difficult to substantiate at
this time.
1.3.1.6
Maltby
On 12th December 2002 UK Coal plc announced that no viable plan has yet been produced for
the mine. At the time of compiling this report UK Coal plc therefore had no approved
production and development forecasts for the mine. However, IMC has since learned that in
early 2003 a new single face plan has been formulated, supported by future investment.
1.3.1.7
Rossington
Currently there are no investment plans in place, however, UK Coal plc has alluded to
potentially increasing output to around 2.0Mt/a at a cost of around £40M. This would include
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 7
substantial repairs to the existing infrastructure and the upgrading of the locomotive system to
high speed. It also includes for the installation of new headgear and skip plant. It is IMC’ s
view that it would be unlikely that the reserve base (3.169Mt Reserve, 7.982Mt Resource)
would support such a large investment.
However, it is also IMC’ s view that significant investment is needed to up-rate the existing
infrastructure to support the present planned output level of 1.2Mt/a. Some 700m of Intake
Roadway require enlargement to improve the ventilation to levels commensurate with
planned development and production. The locomotive transport system also requires to be
extended and improved. The existing reserve base could possibly support such investment
with the assistance of aid. However, an exploration programme would also be of benefit in
first minimising geological risk and proving the extent of the reserve within the current
working area. This could be extended to cover potential areas of coal north of the present
licence area and previously held by the abandoned Markham Colliery. Assuming that a
viable scheme could be prepared then the extension of the main infrastructure roadways could
also be considered as a potential investment scheme.
1.3.1.8
Thoresby
UK Coal plc has at this time put no potential investment plans forward. In mid 2003 output
will transfer from the current working area to the Ollerton Area that is currently being reopened and developed. It is anticipated that this area will sustain the mine until 2008 when it
will reach exhaustion.
The current mine plans do not include the access and development of the Deep Soft
(estimated resource of 7.272Mt) to maintain production at the mine following the exhaustion
of the Parkgate in Ollerton. The seam is relatively thin and in the past has not been
considered to be a viable proposition. To maintain output levels at current levels would
require the adoption of a two-face strategy with its attendant increase in costs. However, UK
Coal plc has indicated that they intend to examine the feasibility of working the Deep Soft.
1.3.1.9
Welbeck
The mine is to transfer production from the Parkgate seam to the Deep Soft in the latter part
of 2004. To accomplish this a substantial amount of work requires to be done in recovering
and re-establishing the old Deep Soft infrastructure.
These works will require significant investment including the up-rating of the main rope
haulage, the extension of the locomotive system, the construction of locomotive and free
steered vehicle garages, the establishment of the mineral conveying system and the build-up
and installation of ventilation booster fans. The bulk of this expenditure is planned to be
undertaken in 2004 and may be considered for investment aid. In addition investment will be
required to extend the existing tip life beyond three years. However the Deep Soft
reserve/resource is limited at an estimated 2.695Mt reserve and 2.721Mt resource and it may
prove difficult to substantiate long-term investment.
1.3.2
1.3.2.1
OTHER INDIVIDUAL MINES
Hatfield
The mine is currently working remnant parcels of the High Hazels seam for which no major
investment is required.
Substantial reserves/resources of the Barnsley Seam are present within both the Hatfield
(8.53Mt Resource and 19.50Mt) and neighbouring Thorne (75.332Mt Mineral Potential)
licence boundaries. Coalpower have outline plans to develop the Barnsley seam, initial access
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 8
being via two relatively short drifts. Longer-term drivages have also been tentatively
proposed to create a base for extending across into the Thorne licence area.
The plans are aligned to the building of a 432MW Power station on site that will be designed
to burn around 1Mt/a of coal. Plans also include for the construction of a second power plant
with the intention of connecting with the Thorne infrastructure and up-rating the mine
capacity to 2Mt/a.
The connection to Thorne would not be completed for at least 8 years from commencement of
the initial access to the Hatfield Barnsley resources. Thorne would therefore require to be
kept on ‘care and maintenance’ for this protracted period. Estimates for this have varied
between £500,000 to £1M/a.
Major investment will be required to access and establish mining within the Barnsley Seam
and Coalpower have indicated that it is not able to fund this from within its own resources and
that it is unlikely that monies will be able to be secured from commercial sources. It must
also be borne in mind that if the High Hazels were to finish prematurely then the mine may
have to go onto a development only basis whilst the Barnsley is accessed.
1.3.2.2
Tower
The current working area will eventually reach exhaustion, production beyond February 2005
being at significant risk from faulting, steep gradients and seam thinning. The opportunity for
investment in this area is therefore limited, although a proving heading to the north, outbye of
the current faces may be considered. The only major anticipated expenditure is the
refurbishment of roof supports.
Outside the present plans for workings in the Seven Feet/Nine Feet Seam the mine is carrying
out longer-term strategic planning. This work is aimed at examining potential options that
might be available within other seams, and accessible by drivages from the present
infrastructure. These feasibility studies need to be completed prior to evolving any potential
investment plans.
1.3.2.3
Aberpergwm
The mine is recovering the old infrastructure and progressively developing west. It is
intended to access and prove some secure areas of coal. Once such areas have been
established through development then there could be potential for generating schemes to
improve extraction techniques. It is estimated for the present that the mine has reserves of
0.48Mt and resources of 3.80Mt.
1.3.2.4
Betws
Betws use traditional hand filled mining methods that are low cost and require minimal
capital investment.
Present plans are for the continuation of Four Feet only (0.32Mt Reserve). However the mine
has outline plans for accessing the Upper Nine Feet Seam (1.40Mt Resource) that lies some
65m below the Four Feet Seam that could provide replacement capacity when the Four Feet
reaches exhaustion. The mine management has indicated that they are actively reviewing
possible methods of access and their investment costs. It is anticipated that the cost should be
restricted to below £1M.
It is important to note that Betws supplies niche markets producing industrial, domestic and
water filtration products. It does not supply the power generation and coking markets and
may therefore be excluded by EU Regulations from an Investment Aid Scheme.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
1.3.2.5
PAGE 9
Eckington
The colliery works a simple pillar and stall system planned to produce around 40,000/a. At
this level of output the mine has a life of around seven years, the estimated reserve being
0.28Mt. The mine therefore has only minimal capital requirements. However, an essential
part of the mine strategy is the introduction of a second load haul dump vehicle to improve
the production cycle. A scheme for the procurement/development of a suitable machine
would probably be considered for investment aid.
The mine also has the possibility of extending its infrastructure to the west to an area outside
its current licence boundary that contains an additional 0.29Mt of resource. This could also
be considered as a potential for future investment aid.
1.3.2.6
Hayroyds
As in the case of Eckington, the colliery works a simple pillar and stall system planned to
produce around 40,000t/a. IMC estimate that around 0.18Mt of reserve and 0.05Mt resources
of Whinmoor seam remain giving a mine life of about four years. The mine therefore has
only minimal capital requirements. However, to enable the forecasted outputs to be achieved
the Company is looking to develop an Auger type machine for coal extraction, the current
mining machinery being limited in use within the anticipated reducing seam section. It is
likely that the mine will therefore be looking towards Investment Aid to assist in the
development and introduction of an auger miner.
1.4
CONCLUSIONS
A recent analysis by UK Coal plc has used an average price for imported steam coal of $34/t
(MCIS forecast). It is also suggested that there is little likelihood of any increases in imported
prices being sustained through the short term. Implications for delivered price for UK Coal
plc can therefore be based on$34/t, resulting in a delivered price to the Aire Valley power
stations of $45/t, £1.15/GJ. Assuming an allowance of 10p/GJ for transport costs of UK
mined coal, this gives a competitive ex-mine price of £1.05p/GJ. This is the same figure that
UK Coal plc have adopted for a production cost target for their deep mine operations.
Realising sufficient operating profits to at least re-invest in the future, would at the above
price require operating costs no higher than £0.90/GJ, this to be applied for medium term
viability of individual deep mines. At present, taking a soft assumption on prices and
ignoring depreciation, this figure could be taken up to £1.15/GJ.
IMC believe that the operating cost levels referred to in the above - £0.90/GJ for financial
viability and £1.15/GJ for short term survival – are the most appropriate figures to use for
planning, taking account of medium term perspectives.
In 1999, the total UK Coal plc Deep Mines were operating at almost break-even. Over the
last three years, 2000-2002, losses could be in excess of £184M. Some 55% of these losses
may be attributed to Selby. UK Coal plc have already announced their intention to close
Selby. Accepting the high level of fixed costs for all deep mines, the shortfall in output
against budget through the same period would appear as a major factor in the recorded loss.
Against the background of reducing proceeds over the past three years, UK Coal plc have
followed a production strategy aimed at driving down costs at all deep mines. Developments
have been reviewed in line with actual production and steered towards a “ just in time” plan
rather than the more cautious approach previously adopted. The associated risks with recent
planning are perhaps best illustrated in the number of face gaps, which have been endured at
many of the mines through the period, with the consequential loss in output. More recently
operational problems at Daw Mill Colliery have increased these losses in output still further.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 10
Accepting the relatively high production costs areas of capital investment are primarily in
roadway drivage and equipment, the latter being either additional or replacement. These areas
could be extended to cover the following: 1. Exploration:
Since the levels of geological risk have been highlighted their reduction
to more acceptable levels before implementing major schemes would appear as a
necessary prerequisite. It is hoped that consideration might be given to including suitably
planned exploration programmes in future applications for investment aid.
2. Efficiency Schemes:
Discussions on possible efficiency schemes directed towards
future production areas have been highlighted at several of the mines visited by IMC.
These schemes include high speed manriding, improvement in underground gas extraction
systems, and beneficial utilisation of the gas at the surface. Additional schemes, which
may attract sales into other market sectors and thereby generate additional income appear
worthy of consideration. Examples of such schemes include investment into briquetting
plants, power generation from mine gas drainage etc. Unfortunately, the EU Regulations
at present are restrictive in supporting these types of schemes.
3. Implementing New Technologies:
It is assumed that there are no new mining
techniques currently available or in development elsewhere in the world that have the
potential to radically change the prospects of the UK deep mines. At the same time it is
accepted that marginal improvements in both technology and performance will be
achieved through the endeavours and expertise of the present mine operators.
Difficulties are now being found with the demand for frequent inputs of investment to
replace the expensive face packages and other associated equipment. This necessary
replacement, together with the high cost drivages to access available resources is a
consequence to sustaining continuing production at all mines.
4. Additional Development Schemes:
The present single face production strategies
together with the availability of two full packages of face equipment are discussed later in
this report. Limiting development lead times to a minimum and accepting resultant face
gaps seems worthy of review at several mines. If revised strategies requiring increased
development to improve lead times on face replacements and also generate periods of
overlap (with two faces available for production) then improved insurance could be given
to achieving planned outputs. As well as insurance, this change in strategy could secure
increases in output to cover additional requirements for investment. These initial
impulses of resources and costs associated with increasing developments could be
considered for investment aid.
5. Mothballing Deep Mines:
In the past, cases have been made for placing mines
under care and maintenance, that is “ mothballing” . Thorne Colliery is an example of a
mine mothballed for many years in the expectations that at some time in the future the
demand will change sufficiently to re-introduce production. Because this mine has a very
restricted underground circuit the annual care and maintenance costs are estimated at
approximately £0.75M. More established mines would require costs in excess of £2M for
care and maintenance. Mothballing allows continued access to strategic reserves.
However, given that the 2002 PIU Report did not see security of supply arguments as
being persuasive, it is questionable whether mothballing would be an appropriate use of
investment aid.
6. .Development Mine Only:
Suspending production at a mine, whilst continuing
development would at the present time be unlikely to appear as a favourable option for
reasons indicated in Point 4 above. The costs associated with these schemes being too
high without revenue from coal sales and therefore no longer considered economic.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 11
Assessments made by British Coal in the late 80’ s concluded that there was little justification
for the development of new mines. Deep mines have now reached a level where in many
cases it is difficult to justify major investment costs against projected markets and profits.
This is clearly shown by the operator’ s difficulty in formulating a robust and realistic enough
five year plan at a number of their deep mines.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 12
TERMS OF REFERENCE
2
On 16 July 2002, Patricia Hewitt, Secretary of State for Trade and Industry, announced that
the DTI would “ commission an independent study of the remaining reserves at existing deep
mines to identify where investment support might be directed” . This statement was given
after the UK Coal plc announcement on the proposed closure of the Selby Mine Complex.
Recently the Department of Trade and Industry has released a consultation document on a
possible investment aid scheme for the UK Coal Industry. Investment would be aimed at
financing projects with a viable future.
It is important to note that the UK Coal Industry has recently been in receipt of operational
aid (since April 2000), the scheme having ended on the 31st December 2002.
2.1
STUDY FRAMEWORK
The aim of this study is to produce an independent study of the remaining deep mine coal
“ reserves” as at the end of 2002. The term “ reserves” applies to areas of coal covered by the
following: 1. Possible to access from present operating mines included in the specification for the study.
2. The methods of working these reserves are not necessarily restricted to those presently
employed or denoted in future production strategies by the operators.
3. Identified areas of coal are not restricted to being covered by current licences or planning
consents.
In both indicating and defining the above “ reserves” IMC will be dependent on the collation
of all relevant data including existing working plans. It also recognises that within the scope
of the study, a degree of validation is required for most areas of coal. Hence the need for
detailed surface and underground visits, together with discussions between senior
management and IMC at the specified mines.
2.1.1
DATA ACQUISITION
In evaluating the viability of “ reserves” the data can be split into three categories as suggested
in the study specification.
2.1.1.1
Geology
IMC Holding Data
•
•
Information from Privatisation Process including Boyds Report 1993, Rothschilds
Information Memorandum.
IMC’ s Review 1998 “ Prospects for Coal Production in England, Scotland, Wales.”
•
Tower; IMC review of long-term options for production, 2002.
•
Hatfield; IMC Due Diligence Report on Hatfield Colliery 2001.
•
Various other reports and plans held in the IMC Library.
The Coal Authority
I5104C
•
Coal Authority licensees with current licences/agreements (this includes Thorne
Colliery).
•
General Development Order boundaries for existing licensees.
•
Access to recent assessment of indigenous Coal Reserves.
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 13
UK Coal plc
•
Five year plans for all operating collieries, updated to October 2002.
•
Latest reserve/resource calculations and plans for all operating collieries
•
Results of recent information obtained from exploration (boreholes/surface and inseam seismics). Also information obtained from recent roadway drivages with
particular reference to the geology of possible future production areas.
•
Assessment of geological risk through discussion with geologists at UK Coal’ s
Harworth Headquarters
Hatfield, CPL
•
The work previously undertaken by IMC in 2001 has provided a strong reference
base
•
An update on latest position with production faces and developments.
•
Detailed assessment of resources potentially available at Thorne and accessible
from Hatfield; note reference is required to information still being held at both UK
Coal plc and The Coal Authority.
Tower
•
Reference to present plans being held at Tower, together with an update on
information gained from recent underground workings and tomographic surveys.
•
Records held at both The Coal Authority and British Geological Survey at
Keyworth.
•
Reference to recent work by IMC on identifying possible areas of coal that might
be available to the mine for medium and long-term production. This includes on
evaluation reserves available in other seams than the present production seam.
Other Small Licensed Mines
•
Information may be scant, in that a regular update of reserves is not necessarily
being undertaken by the operators. Since the licence areas are generally small, this
is not surprising. Nevertheless, evaluation of areas of coal adjacent to these
licensed areas is necessary.
•
Access to plans and data on resources on the periphery to the existing licence
areas. These being sourced from abandoned mine plans held at The Coal
Authority, BGS at Keyworth and information held at IMC.
Further Sources of Data
2.1.1.2
•
Access, with authorisation, to all recent exploration undertaken by IMC
Geophysics Ltd. (at Huthwaite).
•
Similarly, with authorisation, access to Rock Mechanics Technology data held at
Bretby.
Mining
Sources as in Geology
• See above.
The Coal Authority
• As above.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 14
• Bonds held for liabilities such as closure costs and subsidence damage.
• Royalties.
• Production returns.
UK Coal plc
• Short and medium term plans held in the five-year plans for each mine.
• Long-term plans and feasibility studies being undertaken by UK Coal plc. It is
anticipated that much of this information will be direct from discussion at the
mines and Harworth Headquarters.
• Where relevant, a review of the current asset register being held at each mine.
• Access to any in-house reviews on equipment in use and their replacements. Also
plans for future high spend procurements such as complete packages of face
equipment.
• Location of equipment in place for extending the present infrastructure and
equipment required to access future production areas.
• Access to coal washing data and saleable qualities required for each mine. Also
saleable vends, both present and forecasted, for each mine production plan.
• Indication of stocks being held at the mines.
• Data on ventilation requirements, present and future. This would include in-seam
methane contents, drainage efficiencies for production faces and any ventilation
surveys recently undertaken. Information also required to cover issues such as
spontaneous combustion and frictional ignitions.
• Access to safety statistics and highlighting where emphasis is being placed on
areas of concern, if any.
Other Mines
•
•
•
As for UK Coal plc shown above, if available. It is anticipated that much of the
information will be gathered by visits and discussions at these mines.
Production returns to the Coal Authority.
Information already held at IMC.
2.1.1.3
Financial
All mines in study specification
•
•
•
•
•
I5104C
Data covering the last three full years operating results (cashflow).
Latest financial projections associated with the Five Year Business Plan, as in the
case of UK Coal plc. Access also to any sensitivities applied to future projections,
if available.
Through discussion with the coal operators, information required on any major
investment schemes in place and also those that are being planned.
Obtain an understanding on any efficiency/cost saving schemes being either
carried out or planned. In the former case, obtaining a handle on their relative
success and possible application to other mines. UK Coal plc is active in driving
down costs and has created a team (Project £1.05/GJ) to direct efforts in these
areas.
Determine through discussion how any future investment schemes, either with or
without incorporating a new subsidy scheme, might financially benefit the
designated mines.
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
•
PAGE 15
Evaluate present and future financial risks associated with each mine specified in
the study.
2.2
METHODOLOGY
The methodology employed by IMC is based on both satisfying the requirements included in
the study specification and the estimated time available to complete. It has been split into
three parts, although there will be some overlap, due to the time available to complete the
report.
2.2.1
PART 1
This constitutes the start to the study.
1
Examine all holding data.
2
Collate relevant data for each mine.
3
Recognise additional data required and its source.
4
Review and highlight main issues at each mine.
5
Identify requirements for further analysis on each of these issues before the planned
visits. This includes areas that may need validation at each mine, e.g. suitability of the
main underground infrastructure roadways to support long-term production.
6
Structure the mine visits and discussions at the same time and ensure all the main
issues are covered. Also address the same to other interested parties, e.g. the Coal
Authority.
7
Reach agreement with the operators and others on the programme of visits. Also,
through pro-forma type sheets, obtain basic data from each mine. Highlight the areas
to be covered in discussions. Wherever possible, inform the mine operators of the
main issues in good time to prepare their own inputs and submission of relevant
data/plans.
2.2.2
PART II
The components of Part II have been split into three sections as consistent with the
specification for evaluation in the study.
2.2.2.1
Geology
1
Starting from IMC’ s reserve/review in 1998, process and update to the present. This
process will include discounting reserves/resources for: (i)
Those worked through the period.
(ii)
Recent proving of adverse geology/mining conditions which either reduces or
negates access to previously planned areas of coal.
(iii) Performance related issues which have changed the attractiveness of exploiting
previously planned areas of coal.
(iv)
Areas of coal not previously considered in the 1998 IMC Review, either by
being outside the licence area without planning permission, or both, will be
identified.
2
Categorise reserves/resources into the following groups:(i)
Short and medium term, e.g. as shown in the five-year plan.
(ii)
Reserves/resources that are accessible but outside of (I) and relatively low risk.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 16
(iii)
3
4
Resources that are reasonably accessible but are of high risk, requiring further
exploration.
(iv)
Reserves/resources outside of (i), (ii) and (iii), which do not appear viable at
present, but could be considered marginal.
Evaluate the reserves/resources contained in the short and medium term production
areas included in the five-year plans for each mine. High risk areas within the plans
need to be highlighted, together with further exploration, if required.
Further structure the mine visits and discussions with the coal operators to cover the
robustness of the present and future working areas beyond five years.
2.2.2.2
Mining
1
Undertake visits to all mines specified in the study. Decide on the IMC specialists’
input for each mine, including finance and other disciplines as appropriate. For
example, several of the mines are considered gassy relative to others. This may have a
constraint on planned production and developments. Under these circumstances, the
IMC team would direct its attention to understanding the ventilation problems and
their implications, together with possible solutions. Another example is where a
number of mines are having increasing problems with coal washing, resulting in
excessive costs. Such problems would raise the need for a detailed inspection of the
washing plant to evaluate the problems and their possible solutions for further
production.
2
Visits and discussions at the mines may result in some issues becoming increasingly
important and requiring further investigation. Such issues being covered by the
relevant specialist within the IMC team.
3
Critically examine the present infrastructure at each mine and its suitability for longterm production plans.
4
Together with the finance specialists, evaluate planned costs of production for the
short and medium term.
5
Estimate costs of both access and development to potentially viable areas of coal
outside the present five year plans. In addition, estimate their effects on the overall
continuing total costs of production. This assumes continuity of production
throughout whatever period of time is taken.
6
Comment on the associated risks contained in the short and medium term plans.
Extend this assessment to the possible long-term options for both continuity and
longevity of production, this assessment of risk being tabulated and ranked
accordingly.
7
Examine the practicalities of continuing the present planned operations and at the
same time, undertaking additional strategic developments for long-term production
e.g. requirements for additional manpower, equipment, ventilation, power etc.
8
Assess any identified potential or actual investment schemes at each of the mines.
Determine how these may best be part supported by a suitable government subsidy
scheme, if applicable and conforming to the European Commission’ s Regulations.
2.2.2.3
Finance
1
Liaise with financial counterparts at each of the mines specified in the study.
2
Seek to obtain necessary historical data not held at IMC.
3
Examine and evaluate financial statements included in the five-year business plan, if
available. It may be necessary to use a more simplified format for those collieries
outside of UK Coal plc.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4
5
6
PAGE 17
Identify key elements contained in the operating cost statements, which clearly denote
concern in both present and future projections.
Evaluate the financial strengths of the options put forward by the coal operators or
otherwise for long-term production. These would include realistic costs for access
drivages, in-seam development and production, with supporting plant and equipment.
If possible, determine the needs for, or the way in which each mine will source,
investment for future mining schemes.
2.2.3
PART III
This is the final input from IMC to produce an acceptable document:
2.2.3.1
Work plan
The work plan is based on phasing the work components, as laid down in the methodology,
within a period of six weeks. Additionally, it is structured to ensure that sufficient time is
available for IMC specialists to complete their inputs in the sequence required.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 18
IMC WORK PROGRAMME FOR DTI REVIEW
Part 1 (To be examined for each mine)
Examine Holding data
Collate Data for each Mine
Recognise Data Shortfalls
Highlight Mine Issues
Identify Requirements before visits
Structure Mine Visits
Agree Visits with Operators
Week 1
Week 2
Week 3
Week 4
Week 5
Week 6
MT WT F S S MT WT F S S M T WT F S S M T WT F S S MT WT F S S MT WT F S S
Part 2 (To be examined for each mine)
Geology
Examine and discount reserves
Categorise Reserves
Evaluate reserves in present Action Programmes
Evaluate reserves Outside present Action
Mining (To be examined for each mine)
Mine Visits
Delineate Mining Issues
Examine mining implications
Evaluate Production costs in Action programme
Evaluate Production costs outside Action
Analyse risks to Action Programme
Analyse present and future plans
Identify potential schemes
Financial (To be examined for each mine)
Collect and collate data
Examine financial aspects of the business plans
Identify key elements
Evaluate financial strengths of any options
Determine possible future funding sources
Part 3 Reporting
Draft report writing
Incorporating comments
Final Draft Report Preparation
I5104C
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 19
IMC Work Programme of Visits for the DTI Review
Week 1
Week 2
Week 3
Week 4
Week 5
Week 6
MT WT F S S MT WT F S S MT WT F S S MT WT F S S MT WT F S S MT WT F S S
Colliery/Organisation
UK Coal Harworth HQ
Coal Authority
Ellington
Rossington
Kellingley
Aberpergwm
Betws
Tower
BGS Keyworth
Daw Mill
Eckington
Hayroyds
Maltby
Clipstone
Harworth
DTI Progress Meeting
Thoresby
Welbeck
Coal Authority
Hatfield (Including Thorne)
UK Coal Harworth HQ
Meetings as required
UK Coal Mines
Other Deep Mines
Small Licenced Mines
Other NGO’s and UK Coal HQ
I5104C
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
3
BACKGROUND
3.1
OVERVIEW OF MARKET
PAGE 20
Steam coal produced in the UK is restricted by transport cost to sales within the UK. This
domestic market is dominated by power generation; other steam coal uses, including
industrial boilers and cement making in particular, can be considered as marginal and
diminishing consumption not relevant to the medium term economics of coal production.
The UK’ s electricity supply industry (ESI) is a grouping of competing private companies
generating from a range of fuel types – nuclear, coal, gas, renewables. Nuclear and
renewables benefit from state subsidy. The system has excess capacity and short-term interfuel competition exists to a degree (competition is limited by the technical nature of certain
stations and by contractual obligations on fuel supply). In the medium to long term – the
timescale of new build and major refurbishment – competition is total. Coal’ s main strength
is that coal-fired stations are the most appropriate for load-following generation. Its main
weakness is the environmental impact of current generating technologies.
Coal-fired generation accounts for about 32% of UK electricity production. The contribution
of coal is expected by most analysts to decline in the medium term both in market share and
in quantity consumed. For example, UK Coal plc has recently considered a likely reduction
in coal burn of 10Mtce in 2001 – 20031.
3.2
IMPORT COMPETITION
UK-produced coal competes at the coal stations with imports2; nearly 60% of the coal burnt is
imported. There is scope, with relatively minor infrastructure investment, to increase this
percentage further. The UK industry has accordingly become a price-taker – price levels and
the nature (even possibility) of contracts are controlled by international rather than domestic
norms.
Most exporting countries have production costs well below those of UK deep mines, or even
opencast, because they generally have better geological conditions. There are distortions in
the market; some exporters have Government subsidy, others reduce cost by labour practices,
which would be unacceptable in the UK, but the majority is fair competition (e.g. the US,
Australia, South Africa). This ensures that a reasonable approximation to a market will
continue in NW Europe importation and that the UK industry will continue to be a pricetaker.
3.3
IMPORT PRICES
The most common import marker price used in the UK is the MCIS index, a Cif spot price for
steam coal of standard quality delivered to NW Europe ports. Reliable statistics for the index
have been compiled for more than a decade. It shows that import prices exhibit cyclic
tendencies with considerable variation. Over the period 1991 - 2002 prices (in current US
dollars) have ranged between about $25 and $45/tonne with an average around $35. The
cycles are driven by international supply/demand imbalances too complex to analyse here.
For medium term economic appraisal the central value is more important. It should be noted
that there is no consensus among analysts as to whether the central value is flat or declining.
1
UK Coal plc, ESI Market Overview, 15th November 2002 (internal presentation)
UK coal-fired stations are designed to burn bituminous coal with the exception of Aberthaw in South Wales.
This station is designed for low-volatile middlings/ rejects from anthracite mined locally for household
consumption. The general discussion of this section is not pertinent to Aberthaw.
2
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 21
There are good reasons to believe it will not exceed $35 in the medium term, chiefly because
of the cost profile of US production.
In recent analyses (e.g. 1 ESI Market Overview) UK Coal plc has used an MCIS forecast of
$34/t. This is not unreasonable and in fact is the November 2002 MCIS level (we appear at
present to be mid-cycle). This figure will be used for the analysis which follows although we
note that for robustness in planning the sensitivity to say a 10% price shortfall should be
considered; there is little real likelihood of import prices being higher than $34/t on average in
the short-term.
3.4
IMPLICATION FOR DELIVERED PRICE OF UK COAL
UK produced coal competes with imports on delivered price at the power station. It is only in
the power stations close to coal mines that UK producers can compete. The £5/t or so
transport cost advantage that the UK has over imports in, for example, the Aire Valley is
critical to the potential for competition.
Comparison with MCIS price requires assumptions on transport/ handling costs and –
crucially – the £/$ exchange rate. In present conditions an MCIS price of $34/t results in a
delivered price to the Aire Valley power stations of $45/t, £1.15/GJ. Allowing 10p/GJ for
transport cost of UK-mined coal gives a competitive ex-mine price of £1.05/GJ. It is no
coincidence that UK Coal plc adopted this figure as the cost target in their ongoing
restructuring of deep mines, Project 105.
3.5
COSTS, PRICES AND VIABILITY
A medium term MCIS marker of $34/t, and continuation of present transport cost and
exchange rates, suggests that mines have potential for sale at free-on-rail prices of £1.05/GJ.
We have seen that $34 is likely to be high-end and that prudent planning might be betterfocused 10% below this, £0.95/GJ. Achieving a reasonable profit on operations requires cost
to be significantly below this price – a 5% return on turnover with prudent price assumptions
would mean an operating cost no higher than £0.90/GJ for medium-term financial viability of
individual deep mines.
Economic viability – which controls immediate closure decisions – gives a more relaxed test.
Where a mine is cash positive it normally makes sense to keep it in operation until production
cannot continue without further significant investment. The appropriate test for this at present
would involve a soft assumption on prices and striking out depreciation – say an operating
cost of (£1.05 + £0.10) = £1.15. Mines operating above this cost level would appear to lack
even a short-term future unless they are protected by contracts with prices above the level
assumed. It may be noted that this was the cut-off figure for core costs used in the UK Coal
Operating Aid Scheme.
3.6
RECENT DEVELOPMENTS IN THE POWER GENERATION SECTOR
This report is written at a very difficult time for reliable analysis. The ESI is in an extremely
unstable state. The introduction of NETA was followed by a (probably) unsustainable
depression of wholesale power prices. Operators have suffered, TXU and British Energy in
particular, and fuel-buying patterns have been distorted. The Government has intervened with
subsidies for British Energy but has not compensated competing generators.
Coal producers have suffered. To take three examples from UK Coal’ s recent experience:
ƒ
I5104C
Maltby coal was offered in an internet auction in late autumn starting at £0.95/ GJ.
There were no offers.
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 22
ƒ
Signing a two-month contract with Rugeley for the sale of 200,000t was considered
such a breakthrough as to drive the company’ s first press release for months.
ƒ
The company has just withdrawn its planning application for Dawley Road opencast,
expected to be a low cost operation, citing “ changes in the market” .
At the time of writing generators have some 15Mt of coal stocks, almost enough to take them
through a mild winter
It is difficult to disentangle short-term and medium-term effects in the current circumstances.
Some of the immediate problems will be resolved by the development of Government policy
concerning the ESI and the coming White Paper.
Some clear tendencies, which support the previous analysis, do however emerge:
ƒ
Long term contracts are a thing of the past. Much of the international coal trade is
based on individual cargoes and a 12-month contract is probably the best that a UK
supplier can now hope to negotiate.
ƒ
Coal futures (a small but developing market) are trading flat on current prices.
ƒ
There is still a considerable supply overhang in major exporting countries, which
would rapidly squash any tendency for prices to rise above equilibrium levels.
IMC therefore believe that the cost levels presented earlier - £0.90 for financial viability,
£1.15 for short-term survival – are not unduly influenced by current events but are the most
appropriate figures to use in planning, taking account of medium term perspectives.
3.7
OTHER ISSUES
At October 1998, IMC produced a report on the “ Prospects for Coal Production in England,
Scotland and Wales for the DTI” . Since this time, significant changes have occurred in the
UK Coal Mining Sector which have, for the most part, reflected in increasingly difficult
commercial conditions. This has meant that several loss-making mines have had to close
through the period with the resultant sterilisation of their coal reserves. Recognising the
general imbalance between production costs and selling price (generated income) assistance
has been given to selected mines since 17 April 2000. This aid in the form of a government
subsidy scheme will, in its present form, finish at the end of 2002.
In moving forward with the framework of the new investment scheme, substantial evidence is
required to support a “ persuasive case” for granting such aid to the coal industry. To achieve
this, the feedback from the coal operators is of prime importance. Any outline investment
schemes forwarded by the operators will require validation. It is assumed that all these
investment schemes will be associated with the development and subsequent production from
well defined areas of coal. It is also recognised that such areas of coal will be part of the
remaining reserves at existing deep mines covered by this study. IMC is required to highlight
the main issues relating to the specified deep mines, together with the probable schemes for
evaluation in the study in this report.
The investment aid scheme is subject to approval by the European Commission under the
European Council Regulation on State Aid to the Coal Industry (EC No. 1407/2002, effective
from 24 July 2002). It would be covered by “ aid for initial investment” as defined by the
scheme. Aid would be directed as a proportion (capped by EU Regulation at 30%) of capital
costs associated with acceptable investment schemes. These costs would be “ directly related
to infrastructure work or to the equipment necessary for the mining of coal resources in
existing mines” .
Likely time schedules for investment schemes are suggested by the consultation document for
up to three years’ development and a subsequent five years’ production period. Under the
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 23
terms of the state aid regime, an aid scheme could not continue beyond 2010 and total aid for
any one year could not exceed £65m to the industry as a whole.
Since the investment projects are intended to be directed towards maintaining access to viable
reserves, then options are subject to long-term planning i.e. 5 to 10 years and in some cases,
15 years. To remain viable, in the short and medium term, production plans need to be both
realistic and demonstrate a healthy cash flow to support the project through the development
period. It is anticipated that a significant proportion of the investment for the projects will be
derived from the ongoing profitability of each particular mine. Therefore, a critical
examination of the latest five-year production and development plans for all relevant
underground mines is an essential part of validating future reserves. It is also important to
review the last 3 years financial operating data reflecting both production costs and sales
price. This information is essential in determining the validity of the proposed mining plans
by establishing whether the mine has a proven track record to support future investment.
The government’ s Performance and Innovation Unit published an energy review in February
2002. This extensive report on the whole of the UK energy sector covered a period up to
2020 and beyond to 2050. The report highlights the importance of keeping options open to
enable the making of positive responses to changing circumstances affecting the energy
sector. The report also emphasises the need for future energy policies, which reflect “ three
objectives of sustainable development – economic, environmental and social – as well as
energy security” . Whilst the report suggests that “ there is a general agreement that a diverse
energy system – both in terms of types of energy and their sources – can benefit security” this
is not necessarily an agreement for self-sufficiency within the coal industry.
At the end of 2002, many of the UK regional electricity supply companies have expressed a
significant downturn in their present financial prospects. The UK wholesale electricity prices
have fallen by 40% since 1998. Several of these companies have also suggested that power
generation over capacity is a fundamental constraint to their commercial viability. At the end
of 2002, due to difficult market conditions, UK Coal plc undertook a review of mines, which
include Rossington, Maltby and Harworth.
In November 2002, AES Drax declared TXU Europe to be in breach of contract by missing an
October £50M payment for forward supplies. TXU Europe then moved into administration.
During this time TXU Europe sold three coal fired power stations to PowerGen. This sale did
not include the associated supply contracts and being in administration should render this
void. In turn, this should now promote a period of regeneration on coal supply deals, which
may be subject to prices, which reflect weaker market conditions. It can also be expected that
the coal industry’ s position on long-term contracts with the power stations has significantly
worsened, hence increasing the difficulties in obtaining external investment for mining
projects.
Over the last few years, with the deterioration in proceeds, UK Coal plc have based their
strategic plans on minimising costs at all their Deep Mines. Investment, through necessity, has
been in general limited to the replacement of large items of equipment and selective strategic
drivages at nominated mines. Output at all mines, with the exception of Maltby, is planned on
a single face production with rationalised layouts concentrated in discrete areas of coal.
Further developments both for face replacements and strategic access has been controlled to
match these reduced activities.
Accepting that progress has been made in driving down production costs at most mines, in
some instances risks to achieving future planned outputs have effectively increased. UK Coal
plc has recognised some of these risks and is now actively pursuing exploration to reduce the
geological risks inherent in some of the mine plans. Due to the recent changes that have taken
place in the market UK Coal plc have had to respond by making short term decisions. Hence,
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 24
this year the completion of five-year plans for each mine have been delayed and only very
limited long-term plans have been reviewed.
3.8
FINANCIAL OVERVIEW FOR INVESTMENT
Performance is discussed in terms of proceeds, output, production costs, development and
profitability. Potential co-investors will be interested in the industry and company track record
for conceiving projects, developing and implementing them and paying back the investment.
They are also interested in the company ability to consistently control costs at less than the
future price at which they sell it. Profits are important from the point of view of the company
being able to fund it’ s own part of the project as well as a track record of actually making
repayments. This input will also demonstrate the company’ s commitment to the project by
being willing to risk it’ s own resources.
At least 90% of the total UK Deep Mine production is sourced from UK Coal plc. Other
mines have smaller outputs of less than 100,000t/a with the exception of Tower and Hatfield
collieries. The former colliery operating at 600,000t/a and the latter, planning future outputs at
a similar amount. Accepting the limited data available, the hopes and aspirations of the small
mines have respectfully been examined by IMC. Obviously because of their size they have
very limited potential to plan and financially support large-scale projects (greater than £1M)
similar to those in UK Coal plc. Although considered as of no lesser importance to those of
the larger individual mines, these smaller mine projects are likely to have little impact on the
future supply of coal for power generation. Indeed a number of smaller mines have adopted
marketing strategies, which are diverse and more importantly are in other sectors capable of
attracting higher proceeds. Unfortunately many of theses market sectors do not comply with
EU Regulations funding covering aid schemes. As a consequence future major projects are
generally confined to larger deep mines of UK Coal plc, Tower and Hatfield collieries.
Over the recent months the prospects for any improvements in the proceeds for PSF appear
remote. This has left the larger collieries having to concentrate for expediency on finding
solutions to short term problems rather than planning long term projects.
Capital Investment for 2003 at UK Coal plc Deep Mines has been budgeted at £19.5M. This
money is applied to both equipment and capital roadway drivages. In addition UK Coal have
recognised the need to reduce geological risk and capital has been directed towards
exploration in the form of surface seismic surveys and boreholes. Investment has been
limited to seven mines, namely Wistow, Daw Mill, Harworth, Kellingley, Thoresby, Welbeck
and Rossington.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 25
4
ASSESSMENT OF EXISTING DEEP MINES FOR FUTURE
INVESTMENT
4.1
GENERAL INTRODUCTION
4.1.1
GENERAL REPORTING
The majority of the existing mines are operated by UK Coal plc. As operators, they have kept
formal reserve statements and up to date plans available for examination. Because of this, the
style adopted throughout this section of the report for the UK Coal plc collieries is
standardised and tries to be mainly factual.
Other operators have no formal reporting procedures or standard statements for their mines
and this has necessitated a different style of reporting by IMC for these mines. Hence the
style used for other operators tends to be more descriptive and table layout differs from the
UK Coal plc style although attempts have been made to standardise the reporting for these
other operators.
4.1.2
EVALUATION OF RESERVES AND RESOURCES
The Reserves/Resources assessments for most of the mines are based on the guidelines
proposed by the Institution of Mining and Metallurgy (IMM) in 1991 and subsequently
incorporated into the listing regulations of the London Stock Exchange (LSE). These
guidelines are given in Appendix 1 at the end of this report. In general the mineral is
subdivided into Reserves (proved and probable), Resources (measured and indicated) and
Mineral Potential and definitions of these terms are also given in the Appendix.
This section of the review, with regard to reserves and resources, is primarily concerned with
those portions of the mineral that are considered recoverable within the current plan and with
regard to the current economic conditions.
Regarding UK Coal’ s mines, as the system of reserves classification was the same under the
last review in 1998, a comparison can be made directly of the two assessments and reasons
examined and justified for any changes that have been made.
4.1.3
EXPLORATION AND RE-CATEGORISATION OF RESERVES
In this study, one of the objectives was to try to define areas of coal that require exploration to
either bring them into the reserve categories if they are outside any present licence boundary,
or to raise the category of those zones that are at present within licence and are of interest to
the mine.
IMC have attempted where possible to highlight both these types of situation if they exist at
the mines under consideration. IMC have also examined areas of coal that they consider, for
various reasons, are placed in categories that are too high and need to be re-categorised to
show the true situation as it stands at the present time.
This, however, does not mean that these re-categorised areas of coal are lost for all time.
Reserve estimation is dynamic as the situation is constantly changing as either working
progresses or further exploration is completed increasing the geological and mining
knowledge of the zones in question. If either the mining situation or the results from
exploration are favourable, then these questionable zones or seams could be re-assessed in the
light of the new information and brought back into consideration.
Any further knowledge of the seams has the effect of decreasing or increasing the geological
risk to mining and this is reflected in the movement of various zones from the lowest category
of Mineral Potential through to the highest category of Proved Reserve or vice versa.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 26
The following map shows the existing deep mines that are considered in this study for the
assessment of the reserves.
Location of Deep Mines
100 Kms
Edinburgh
Glasgow
Collieries, UK Coal
Collieries, Other Operators
Collieries, Small Mines
Ellington
Newcastle
York
Wistow
Gascoigne Wood
Kellingley
Hay Royds
Stillingfleet
Ricall
Thorne
Hatfield
Rossington
Doncaster Maltby Harworth
Eckington
Sheffield
Welbeck Thoresby
Nottingham
Daw Mill
Birmingham
Betws
Aberpergwm
Tower
Cardiff
Figure 4-1
I5104C
Coventry
London
Location of Existing Deep Mines
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.1.4
PAGE 27
OPPORTUNITIES FOR FURTHER INVESTMENT
Generally the majority of the larger mines have investment programmes. In the main this is
confined to replacement or additional equipment that is necessary to fulfil the short and
medium term operational plans. Other than for strategic development drivages at Kellingley
there are no schemes currently in progress that are directly associated with the accessing of
new reserves.
From discussions it is apparent that there is a unanimous view that financial institutions are
risk averse to mining. Operators are also finding it more difficult to secure long-term sales
contracts to substantiate applications for financial assistance for investment. It is therefore
considered doubtful that, as investment aid is confined by EU regulations to 30% of the total
cost of the project, the remainder could be funded from elsewhere other from within the
company’ s own resources. The viability of the short-term mine plans is therefore paramount.
In many instances, particularly at the smaller operations there is no collateral to offer as
security against loans.
However, the operators have put forward a selection of schemes that could potentially qualify
and be undertaken with the assistance of investment aid. The projects have only been offered
in outline with ‘ball park’ budgets and need to be developed in detail to ascertain their
viability. These are listed below with IMC’ s view as to whether they are self-supporting
(Category 1), would benefit from an investment scheme (Category 2) or are ideas that would
need a much stronger market situation before they could become a reality (Category 3).
UK Coal plc has £19.5M of capital spend programmed for 2003. It must be recognised that
this is mostly for replacement equipment and some developments that access reserves for
exploitation within the next few years. This expenditure should generally be considered
Category 1 since it is virtually committed and is to maintain current activity.
In addition, the closure of Selby is expected to release a capital equipment surplus and
management are expected to dictate that this should be used before turning to new purchases.
However, the cost of maintaining the mine infrastructure is high and the opportunity for the
removal of equipment may be limited as the cost of salvage may be prohibitive.
UK Coal plc has recognised areas of high geological risk that are contained within the future
plans at several mines. Capital expenditure is therefore being directed in the first instance to
geological exploration designed to minimise this risk. It is hoped that this work will benefit
future schemes that are based on the development of these areas.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 28
UK COAL PLC MINES
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.2
CLIPSTONE COLLIERY
4.2.1
BRIEF DESCRIPTION OF SITE
PAGE 29
Clipstone Colliery is located in the village of New Clipstone approximately 5km north-east of
Mansfield in Nottinghamshire. The colliery is connected to the national rail network to the
north via a branch line.
The colliery was originally sunk in 1922 to exploit the Top Hard Seam. In the early 1950’ s,
the shafts were deepened in order to access and exploit reserves in the Deep Soft, Low Main
and Yard seams. The Top Hard Seam was worked extensively from mine commissioning in
1923 through to 1961. Following the deepening of the shafts, production in the Low Main
Seam was introduced in 1956. The Low Main was worked utilising fully mechanised
longwall extraction methods until 1989.
In the early 1970’ s two pairs of drifts were driven from the Low Main to access the Deep Soft
and Yard seams. Production from the Yard Seam commenced in 1974 and from the Deep
Soft in 1975.
British Coal closed the mine in 1993 and it was reopened in April 1994 by RJB Mining (later
to become Harworth Mining Ltd), under a SECTION 36, (2), (a) licence. Clipstone’ s licence
comprises areas in the Yard and Deep Soft Seams at depths of some 760m and 880m
respectively.
Harworth Mining Ltd is to cease production at the mine in the middle of next March and hand
the licence back to The Coal Authority on the 31st March 2003. The Authority therefore
posted a notice on the 25th November 2002 “seeking expressions of interest from prospective
operators of sufficient financial standing to secure the physical integrity of the mine and to
invest in its renewed development as an active mine” . Responses were to be made by 13th
December 2002. If an alternative operator cannot be found then the mine will close following
the return of the licence to The Coal Authority.
4.2.2
MINE BOUNDARIES, OTHER SURFACE CONSTRAINTS AND ISSUES
Adjacent collieries are on all sides and define the licence area. To the south and west are the
closed collieries of Rufford, Mansfield and Warsop. In the north and east the boundaries are
aligned to the working mines of Thoresby and Welbeck.
4.2.3
GEOLOGICAL ASSESSMENT
Clipstone lies in the central Nottinghamshire part of the concealed eastern Pennine Basin
Coalfield. The Coal Measures dip gently eastwards, beneath unconformable Permian and
Triassic formations. The main seams of interest lie at depths of around 900m. The PermoTriassic formations, and the thin superficial deposits, are not relevant to workings at these
depths. The local Coal Measures are typical for this part of the coalfield. There are no igneous
features of any mining significance.
4.2.3.1
Structure
The Coal Measures are only gently deformed. Bedding dips are greater than c. 20 only in the
south and east, where recent panels in the Yard Seam proved full dip, to the northeast, of up
to 70. The major Mansfield Anticline, and associated large faults, lies south and southwest of
the Clipstone area, and is not relevant to this report.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 30
There are a few fault zones on a general NW-SE trend. These tend to have maximum throws
in low 10’ s metres or less, in the lower seams. The zones themselves usually include more
than one main fracture, within an overall faulted width of up to 100m, and there is local
associated folding within the zones. High stress settings have been known immediately
adjacent to the larger faults near Clipstone.
The main cleat orientation is NW-SE, with a few deviations close to certain faults.
Small faults (typically <1.5m throw) are expected to lie along the roof and seam disturbances
(channel sandstone roofs, and seam swilleys) that are described in later sections. These are
related to the depositional environment.
4.2.3.2
Seams in Reserves
The following seams are considered to be in the reserve/resource classification for this mine.
•
Yard Seam
•
Blackshale Seam
Yard Seam Characteristics
The name Yard, as used at the mine, comprises the Yard Seam of the wider coalfield, plus the
upper (4th) coalbed of the underlying Blackshale Seam. This usage is adopted here.
The roof is typically a thick mudstone, although small channel sandstone belts are known or
inferred to lie above the seam in places. It is thought that these have had limited adverse
effects at Clipstone. The immediate working roof on the faces may include coal and
mudstone, depending upon local extraction practice.
The seam is typically 1.15m to 1.45m thick, commonly with a thin (0.01m to 0.04m) dirt
layer near the top. Very locally, seam sections include a thicker, near-base dirt, but this is
exceptional. Most analysed sections are dirt-free. Seam-less-dirt ash varies around 5% to
10%; seam-less-dirt sulphur varies typically between 1.3% and 2.3%; seam-less-dirt chlorine
varies around 0.40% to 0.50%. The seam is high volatile, bituminous rank (NCB Coal Rank
Code 502/602). Overall, it has a relatively high rate of change in thickness and ash content.
The immediate floor is generally up to 1.5m of fairly soft mudstone seatearth, with stronger
material below. There is a local floor coal, which is invariably underlain by siltstones.
There are no cover problems with respect to Permo-Triassic formations, or with respect to any
major Coal Measures sandstones. It is noted that other seams have been extensively worked,
and it is assumed that any significant underground water ponds are well known.
Blackshale Seam Characteristics
The name Blackshale, as used at the mine, comprises the three lower coalbeds of the
Blackshale in the wider coalfield. This usage is adopted here.
The Blackshale roof is variable across the Clipstone area. These variations all relate to the
changing interval between the Blackshale and Yard seams, summarised as follows for the area
of interest.
•
Across the northern margins of the mine, a thicker interval corridor is present, trending
W-E, within which the seams are separated by >20m. A channel sandstone system
occupies this corridor, the sandstones being locally >15m thick. In the workings of the
closed Shirebrook Colliery, to the west, this channel system was associated with
significant washouts of the Blackshale Seam, and related disturbances. The boundaries of
the channel sandstone are reasonably well defined at Clipstone, although it may lie rather
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 31
more to the north than presently mapped. Within the channel sandstone belt, the seam is
considered unworkable, irrespective of any other geological variation, because of
washouts, and local difficult roof (especially where a soft immediate roof would fall away
below the stronger channel deposits).
•
The immediate roof away from the channel belts is also variable. It is expected to be
stronger where the Yard/Blackshale interval is >10m, where it is possible that a full seam
could be extracted without leaving supporting top coal; this comment applies to the laidout area. Elsewhere, c. 0.15m of coal would probably have to be left for roof support.
The following notes summarise the complex seam variations in the area of interest.
•
The Blackshale as defined earlier includes two in-seam dirt layers, which separate the
seam into three regionally well-known coalbeds. These splits do not develop widely
within the Clipstone area, but the dirt layers are expected to be locally thicker within, and
along the margins of, a known cannel belt. This cannel belt is known, from mine
workings well to the southwest, and also from intermediate boreholes, to be present within
the Blackshale. Along this belt, the seam is characterised by cannels and thicker in-seam
dirts.
•
Seam thickness, including the two dirt layers, is generally between 1.20m and >1.50m
across the Clipstone area. Locations >1.50m thick are generally related to the abovementioned cannel belt, and within axial zones of the swilleys.
•
The Blackshale has a seam-less-dirt ash content around 8% to 10% across much of the
area, with an increase to >12% in the neighbourhood of the cannel belt. The seam-less-dirt
sulphur content is high, generally between 2.5% and 4.0%.
•
The uppermost subsections of the seam are amongst the cleanest regarding both ash and
sulphur, and extraction below a supporting coal roof would be detrimental to marketing.
•
Chlorine contents are moderate to high (0.24% to 0.55%). The seam is a high volatile,
strongly to weakly caking coal, NCB Coal Rank Code 500 to 700 (typically 500).
The floor is poorly known over much of the area. The following generalities apply in the area
of interest.
•
The immediate 2m of floor strata are generally weak mudstones over most of the area
north of Northing 364. This is likely to lead to floor instability. To the south, the
immediate floor is locally siltstone, or mudstone seatearths up to 1m
4.2.3.3
Reserves/Resources Assessment
UK Coal’ s assessments for January 1998 and July 2002 (and January 2000, for the
Blackshale) have been provided for this study.
Position with regard to Reserves in 1998
The reserves/resource available at Clipstone in 1998 were as summarised in Table 4-1 below
based on the knowledge at that time.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table 4-1
PAGE 32
Clipstone: Reserve/Resource Summary January 1998
(Source: UK Coal plc)
Million Tonnes
Seam
Reserve
Resource
Total
Mineral Potential
Yard
3.2
None
3.2
None
None
None
None
None
3.2
None
3.2
None
Blackshale
Total
Position with regard to Reserves/Resources in 2000 and 2002
The following table gives a summary of the reserve/resource position at Clipstone with regard
to assessments made in January 2000 (Blackshale Seam) and July 2002 (Yard Seam)
Table 4-2
Clipstone: Reserve/Resource Summary January 2000 & July 2002
(Source: UK Coal plc)
Million Tonnes
Seam
Yard (July 2002)
Blackshale (January 2000)
(Not in 2002 assessment)
Total
Reserve
Resource
Total
Mineral Potential
0.3
None
0.3
None
None
None
None
2.4
0.3
None
0.3
2.4
Changes between Reserve Assessments
The following table, Table 4-3, shows in detail the comparison between the assessments in
1998 and 2000/2002. In general the main changes are in the depletion of the Yard Seam
reserve. This is largely extraction, (c. 3Mt over 4.5 years).
The inclusion of 2.4Mt of technically recoverable Blackshale Seam in the year 2000 increases
the Mineral Potential of the mine. It should be noted here that the Blackshale is not shown in
the UK Coal’ s 2002 statement. The seam is thin, quoted at a seam thickness of 1.3m to 1.4m
but is compatible with regional trends. The seam-less-dirt sulphur, quoted as >3.0%, is also
compatible but very high.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 33
Table 4-3
Clipstone Colliery: Reserves and Resources Comparison
1998
SEAM
YARD
BLACKSHALE
TOTALS
I5104C
RESERVE (Mt)
2002
RESOURCE (Mt)
Mineral Risk Factor Block
Potential
or
Probable Measured Indicated
Tect Sed Panel Zone
(Mt)
RESERVE (Mt)
RESOURCE (Mt)
Mineral Risk Factor Block Change Reason for Change
Potential
or Panel
Probable Measured Indicated
Tect Sed
(Mt)
Zone
Proven
Ae
0.4
-
-
-
-
1
2
P
-
-
-
-
-
-
-
-
-
-0.4
Aw
0.5
-
-
-
-
1
2
P
-
-
-
-
-
-
-
-
-
-0.5
Bn
-
1.0
-
-
-
2
3
P
Bn
0.3
-
-
-
-
1
1
P
-0.7
Bs
1.3
-
-
-
-
2
2
P
-
-
-
-
-
-
-
-
-
-1.3
-
-
-
-
-
-
-
-
-
An
-
-
-
-
2.0
1
3
P
+2.0
-
-
-
-
-
-
-
-
-
Bn
-
-
-
-
0.4
1
4
P
+0.4
2.2
1.0
-
-
-
0.3
-
-
-
2.6
Proven
Part worked. One unit deleted because of expected swilleys.
Technically recoverable; classed as Mineral Potential mainly because of quality.
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
Y4
Y1
Y3
Y2
Figure 4-2
RUFFORD COLLIERY
YARD SEAM WORKINGS
N0 2 SHAFT
N0 1 SHAFT
Y199
460000
0.1
BO
U37N
DA
RY
1.3
0.6
0.3
0.1
0.6
0.3
0.2
0.6
0.4
0.3
39
0.3
0.2
0.2
0.1
0.2
0.2
0.1
0.2
0.1
0.1
41
0.3
0.7
0.4
0.7
Clipstone Colliery Yard Seam Plans
LIC
EN
CE
0.4
0.5
0.2
0.3
0.1 0.4
0.3 0.3
1.0
0.7
0.4
0.9 0.3
0.3
461000
I5104C
Y201
Y200
Y194
Bn
362000
Y206
Y203
Y202
Y198
Y196
65
0.2
63
RY
NDA
BOU
E
ENC
LIC
363000
364000
Y205
Y204
flea
ain
fM
o
Top
sh
ha
Hig
ING
LT
AU
EF
IBL
SS
PO
365000
366000
367000
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
0.6
0.2 0.2
51
1.0
0.9
1.3
1.3
27
1.3
1.8
0.9
N
0.4
4.4
0.2
CENTER
PARCS
SUPPORT
PILLAR
at
Cle
of
e
Lin
0.6
0.5
463000
462000
459000
458000
457000
183
TOP HARD SEAM
DUNSIL SEAM
Y194R
FACE
2002
0
2003
500
NOT TO SCALE
10
2.3
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
1000m
DATE AUGUST 2002
2006
Y
835
848
873
884
763
775
711
598
583
520
443
459
399
343
170
+ 87
Depth
Metres
300T
1000T
5
RESERVE AREAS
YARD SEAM
Y
815
270
S.S.S.I.
2005
D 21
C 104
11
13
25
60
12
62
113
15
63
61
16
44
63
173
170
Interval
Metres
COLLIERY OPERATIONS
2004
CLIPSTONE COLLIERY
U.K.COAL MINING ( DEEP MINES ) LIMITED
YARD SEAM
SEAM
Agreed Pillars
Site of Special Scientific Interest
Boundary
Horizontal Bunkers
Strata Bunkers
Faults: Proven
Probable
Possible
Fault throws shown in Metres
Belt Conveyors
Existing
Proposed
Seam Section in cms
Boreholes
Depth in Metres
REFERENCE
122
BLACKSHALE SEAM
SEAM CODE LETTER
Contours in Metres B.O.D
158
175
43
107
36
THREEQUARTER SEAM
YARD SEAM
LOW MAIN SEAM
DEEP HARD SEAM
DEEP SOFT SEAM
CLAY CROSS MARINE BAND
117
HIGH HAZLES SEAM
97
61
23
61
Section
cm
CLOWNE SEAM
MAIN BRIGHT SEAM
MANSFIELD MARINE BAND
HIGH MAIN SEAM
BASE OF PERMIAN
SURFACE ( Above Ordnance datum ).
STRATA
GENERAL SECTION TAKEN FROM SHAFT SINKING AND BOREHOLE RECORDS
PAGE 34
Y208
Y203
Y202
Y5
Y1
Y3
0.6
Figure 4-3
Y4
Y201
0.9
0.9
Y198
Y2
Y196
460000
An
RY
DA
UN
O
B
CE
EN
LIC
LIC
EN
CE
BO
UN
DA
RY
LI
CE
NC
E
BO
UN
DA
RY
Clipstone Colliery: Blackshale Seam Plans
RUFFORD COLLIERY
YARD SEAM WORKINGS
N0 2 SHAFT
N0 1 SHAFT
Top dir
t 10 cm
Top dirt 20 cm
Top dirt 30 cm
461000
I5104C
361000
362000
363000
Y211
An
Y205
Y204
An
Y206
f
lea
ain
fM
o
Top
ash
igh
-H
Y200
An
364000
F
OO
DR
BE
UR
T
DIS
KS
OC
BL
TED
L
I
HT
WIT
Bn
365000
366000
367000
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
N
464000
463000
462000
459000
458000
457000
456000
455000
STRATA
FACE
Y208R
Y196R
2000
Existing
Proposed
D 21
C 104
11
13
25
60
12
62
113
15
63
61
16
44
63
173
170
Interval
Metres
Y
10
2.3
BLACKSHALE SEAM
0
500
Edged
Green
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
1000m
DATE JANUARY 2000
SCALE : 1/10,000
CE005YR
RECOVERABLE RESERVES
REFERENCE
Y
Edged
Green
300T
1000T
5
270
835
848
873
884
763
775
711
598
583
520
443
459
399
343
170
+ 87
Depth
Metres
COLLIERY OPERATIONS SOUTH
CLIPSTONE COLLIERY
R . J . B . MINING ( DEEP MINES ) LIMITED
YARD SEAM
SEAM
Return Airways
Intake Airways
Agreed Pillars
Agreed Pillars
Built Up Areas
Boundary
Booster Fans
Horizontal Bunkers
Strata Bunkers
Belt Conveyors
Faults: Proven
Probable
Possible
Fault throws shown in Metres
Seam Section in cms
Boreholes
Depth in Metres
REFERENCE
122
SEAM CODE LETTER
158
BLACKSHALE SEAM
175
43
107
36
THREEQUARTER SEAM
YARD SEAM
LOW MAIN SEAM
DEEP HARD SEAM
DEEP SOFT SEAM
CLAY CROSS MARINE BAND
97
183
117
HIGH HAZLES SEAM
TOP HARD SEAM
DUNSIL SEAM
61
23
61
CLOWNE SEAM
MAIN BRIGHT SEAM
MANSFIELD MARINE BAND
HIGH MAIN SEAM
BASE OF PERMIAN
Section
cm
GENERAL SECTION TAKEN FROM SHAFT SINKING AND BOREHOLE RECORDS
SURFACE ( Above Ordnance datum ).
PAGE 35
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.2.3.4
PAGE 36
Exploration
Geological structure. No exploration for structural features is considered necessary.
Yard Seam. No further exploration is necessary.
Blackshale Seam. No further exploration is planned for this seam
4.2.3.5
Other Seams of Interest
Apart from the Yard and Blackshale, other seams that achieve workable thicknesses in the
Clipstone area have been extensively mined (High Hazles, Top Hard, Deep Soft, and
Tupton/Low Main seams). A few further seams are very locally as thick as some of those
mined, including the Parkgate (part), and the Ashgate/Mickley (c. 10m below the Blackshale).
Of these, only the Ashgate/Mickley is well developed over much of the area. The seam is
typically between 1.05m and 1.45m thick, including thin dirt layers. Detailed mapping of the
seam is beyond the scope of this report; but this seam is not considered as a viable mining
option.
4.2.3.6
Geological and Reserve/Resource Conclusions for Clipstone Colliery
The following conclusions are drawn.
The Yard Seam will be exhausted, with respect to economically viable workings, when the
Y194 is finished.
Access to the Blackshale Seam from the Yard Seam is also relatively easy, the seams being
separated by only c. 15m at the southeastern (access) side of the block.
The main geological problems associated with this area of Blackshale are expected to be the
sulphur content: without blending, the product may prove difficult to sell for electricity
generation and the generally thin section of the seam.
4.2.3.7
IMC’s Commentary on the Reserves and Resources
IMC’ s comments are as follows.
Overall comment: the depletion of Yard reserves (c. 3Mt over 4.5 years) largely reflects
extraction. A panel northeast of Y199’ s has been deleted from the reserve because of swilleys
proved on the Y199’ s. Only Y194’ s remains in the reserve and that is presently being
worked.
The inclusion of Blackshale as mineral potential follows investigations into the possibilities of
extending the mine’ s life, in a technically-accessible area with generally low geological risk;
the mineral potential classification reflects the seam’ s overall poor quality and thickness.
UK Coal’ s assessment for the Blackshale was based on a full seam extraction (no supporting
top coal being allowed for), and calculated for five longwall units to the northwest of the
shafts, largely beneath Yard extractions. It is possible that full extraction could be achieved
in this area, although some roof instabilities would be expected. The northwesterly limits of
some of the proposed panels would lie beneath the area of sandstone roof, with potential
washouts. Most of the laid-out area would be outside this zone, which would be proved
incrementally by north-going mine workings.
The quoted Blackshale Seam thickness (1.3m to 1.4m) is compatible with regional trends.
The seam-less-dirt sulphur, quoted as >3.0%, is also compatible. The seam-less-dirt ash may
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 37
be slightly less than quoted, at around 9% for much of the laid-out area.
southeasterly parts of the layout may encounter the cannel belt described earlier.
The more
The mine’ s GDO for the Blackshale is far less extensive than the area designated by the lease
licence boundary.
The following table, Table 4-4 is a copy of Table 4-2 above but for completeness shows
IMC’ s assessment summary of the reserve/resource at Clipstone Colliery
Table 4-4
IMC Re-assessment of Clipstone Reserve/Resource Summary: (01/12/02)
Million Tonnes
Seam
Yard (July 2002)
Blackshale (January 2000)
(Not in 2002 assessment)
Total
4.2.4
Reserve
Resource
Total
Mineral Potential
0.3
None
0.3
None
None
None
None
2.4
0.3
None
0.3
2.4
MINE CHARACTERISTICS AND CONSTRAINTS
UK Coal plc are presently working the last face in the Yard seam, Y194’ s. All developments
were stopped in March 2002 and the manpower level stands at 167. The seam has thinned in
the present production area and is only 1m thick at best. Whilst standards and general
conditions in the working district are excellent, excessive dirt is being taken on the face
resulting in a poor quality ROM. Continuing to operate in similar conditions would not be
viable. Despite the endeavours of a committed workforce the mine has operated at a loss over
recent years.
At March 2003, UK Coal plc plan to hand their licence to operate the mine back to The Coal
Authority. The latter as described above have already advertised for an ‘expression of
interest’ from other coal operators to work the mine under a new Part (II) licence (Coal
Industry Act 1994).
On examination it would appear that the only areas of coal that might be of any interest are in
the Blackshale seam some 11m to 15m below the workings in the Yard seam. It should also
be noted that planning is restricted to a limited area under the two previously worked panels
Y199’ s and Y197’ s and east of the shaft pillar. The estimated extractable tonnage is 1.3Mt.
To access and work additional extractable coal in the north, the GDO limits would need to be
extended through gaining new planning permission from the Local Authority. At present there
is no certainty that this would be granted.
The quality of the Blackshale Seam at Clipstone is poor with high sulphur content, which
would result in reduced proceeds. Some areas of the seam are also affected by the presence of
cannel coal. Without blending with better quality coal the product may prove difficult to sell
as PSF.
The mine infrastructure from the Shafts to the Booster Fans will require some repairs to
support extensive operations in the Blackshale Seam. In any long term plans consideration
should be given to increasing the overall cross-sectional area of the main return. This work
could prove both costly and time consuming.
Since all developments have been stopped in March 2002, any incoming operator would be
faced with development and support work for at least 15-months prior to commencing
production. This assumes that a conventional longwall retreat face would work the coal.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 38
Significant replacement costs would be needed if the face equipment were to be partly
salvaged from that already available in the mine. Any new operator would be faced with high
initial costs with no real income. Once production was established the costs of production
would be at the best comparable with those associated with working the Yard seam. As
mentioned, further costs would be incurred in repair works to the return infrastructure.
Although expressions of interest may be made to operate the mine in the future, IMC would
suggest that the prospect of new operators taking over is extremely unlikely.
4.2.4.1
Subsidence
Yard Seam
Reserve Zone Bn: This area is planned to be worked by Panel Y194’ s and properties will
be affected in and around Old Clipstone Village. There is a mineral railway in the area and
drainage problems will be experienced around the River Maun. Fissuring is known to occur in
this area.
Subsidence damage costs are estimated to be around £1/t.
Blackshale Seam
Reserve Zone An: The River Maun lies along the south edge of this area and a mineral
railway line will be affected. Subsidence damage costs are estimated to be around 50 pence/t.
Reserve Zone Bn: The panel in this area also affects the River Maun and railway and costs
are estimated to be around £1/t.
4.2.4.2
Coal Preparation Facilities
ROM is processed through a simple barrel washer and the majority of the product is sold as a
PSF.
4.2.5
4.2.5.1
HISTORIC PERFORMANCE
Production
Table 4-5
Historical Production Performance at Clipstone
Clipstone
1999
2000
2001
Actual Output
million tonnes – saleable
0.523
0.325
0.420
Budgeted Output
million tonnes - saleable
0.550
0.380
0.501
Difference
million tonnes - saleable
-0.027
-0.055
-0.081
The reduction in output in 2000 reflects the decision to close the mine that was subsequently
reversed following the introduction of the UK Coal Operating Aid Scheme in April of that
year.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.2.5.2
PAGE 39
Development
Table 4-6
Historical Development Performance at Clipstone
Clipstone
1999
2000
2001
Actual Developments
metres
1,297
648
1,014
Budgeted Developments
metres
1,752
nil
2,148
Difference
Metres
-455
+648
-1,134
Developments had ceased in late 1999 as part of the closure plans that were in place at that
time, hence no drivages were included within the budget for 2000. Similarly, developments
have stopped in early 2002 following the decision to cease production at the mine in March
2003 and return the operating licence to The Coal Authority.
4.2.6
FUTURE MINING PROJECTION
All development ceased at the mine in March 2002. Mining activity is confined to the
working of Y194’ s retreat face, which is planned to remain in production until 14th March
2002.
4.2.7
PRODUCTION AND DEVELOPMENT FORECASTS
Production for 2002 is expected to be limited to around 245,000t. Y199’ s advance face
operated in the first half of the year ceasing production in June. There followed a gap in face
output of some 3 months as Y194’ s Retreat Face was prepared for production. Following the
establishment of the face in the period September/October, Y194’ s has progressed
satisfactorily, producing around 10,000t/w.
It is planned to continue to operate Y194’ s face at around 10,400t/w until 14th March 2003.
This will give a two-week period for the site to be prepared for the Licence to be handed back
to The Coal Authority on 31st March 2003. The face is phased at a rate of 10 shears per day,
which is equivalent to 30m/w. This results in an overall tonnage for 2003 of 112,300t. It is
anticipated that around 60m of face run will remain at the 14th March giving scope for
additional output should face performance exceed expectation.
4.2.7.1
Longer Term Plans
As previously stated the Coal Authority has sought expressions of interest from prospective
operators to take over the mining operations beyond 31st March 2003. Given the limitations
of the Blackshale Seam in terms of thickness and quality, the need to apply for and gain
extension to the GDO boundary and the protracted development time before the mine returns
to production, IMC consider the colliery not to be viable. It is therefore most likely that the
mine will close following the return of the licence at the end of March 2003.
4.2.8
OPPORTUNITIES FOR FURTHER INVESTMENT
This mine is due to close in March 2003 and has no realistic opportunities for investment.
Any potential new operator is unlikely to be impressed by recent financial performance and
convinced to invest further.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.3
DAW MILL COLLIERY
4.3.1
BRIEF DESCRIPTION OF SITE
PAGE 40
Daw Mill is situated in the Warwickshire countryside, 13km north west of the City of
Coventry, adjacent to the B4098 road, 2km south east of the village of Furnace End. Junction
4 of the M6 Motorway and Junction 9 of the M42 Motorway are 10km and 12km respectively
from Daw Mill. The colliery is connected to the rail network.
Daw Mill No 1 Shaft was sunk between 1956 and 1959, initially as a ventilation shaft for
Dexter Colliery. Coal winding from Daw Mill commenced in 1965. The second shaft was
established between 1968 and 1971. Drivage of a surface drift, which started in 1978, was
completed in 1982.
The main colliery site covers an area of around 40 hectares and has comprehensive surface
facilities including a coal preparation site and coal stocking areas.
Daw Mill Colliery has worked exclusively in the Warwickshire Thick Coal Seam, extracting
an upper leaf, and where seam section allowed, a lower leaf. In 1992, due to poor geological
conditions during development, lower leaf panels were removed from the production strategy
for the mine.
The mine is now established in a large area to the south of the M6 Motorway and has recently
installed a set of new face equipment that allows the extracted height to be increased to 5.0m.
It is envisaged that the increase in the worked section will result in output being raised from
1.9Mt to in excess of 3Mt/a.
4.3.2
MINE BOUNDARIES, OTHER SURFACE CONSTRAINTS AND ISSUES
Mine boundaries are defined by previous old workings to the north (Daw Mill), in the east by
Coventry Colliery old workings, by geological features in the west and the present GDO
boundary in the south.
Within the licence area, there is a single workable seam, the Warwickshire Thick, which is
formed by the merging of seven individual seams. The combined seam varies in thickness
from 6.6m to 7.5m and has an average sulphur content of 1.8%. The mine produces coal
normally at a vend of 95%.
4.3.3
GEOLOGICAL ASSESSMENT OF THE MINE
Daw Mill lies in Warwickshire at the southern margins of the Pennine Basin Coalfield. The
reserve area is limited to the west by the Western Boundary Fault, to the north by existing
Daw Mill workings, and to the east by old workings from the closed Coventry Colliery. The
southern limit is the current GDO boundary, although some resources are shown beyond this.
These resources were previously allocated to the proposed Hawkhurst Moor Mine that was
not constructed.
Upper Coal Measures outcrop over most of the area, overlain in part by local thin Triassic
strata. There are no known igneous features of mining significance in the area of interest.
4.3.3.1
Structure
In addition to the north-south trending Western Boundary Fault, there is also the Fillongley
anticline which is a major faulted structure trending southwest-northeast through the central
part of the mine area, and the Keresley Fault, a large NW-SE reverse structure. Between
these two features, areas of disturbed coal are locally known, at least some of which could be
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 41
interpreted as thrust faults. Other faults are proven from workings and projected from surface
seismic surveys. In the proposed working area (30’ s and 300’ s) the seam dips to the south and
southeast at an average of 3-4°.
4.3.3.2
Seams in Reserves
The only seam in the reserves is the Warwickshire Thick Coal which is a composite
comprising the Two Yard, Bare, Ryder, Ell, Top and Bottom Nine Feet, and High Main
seams. The Smithy seam is close below the Warwickshire Thick Coal in some areas, but is of
poor quality and is not included in the reserves. At other mines where these seams are not
combined, some of them were worked independently.
Seam Characteristics
The roof of the Thick Coal is generally mudstone up to 5 m thick, passing up to stronger
siltstone and occasional sandstone beds. Underground exposures are limited due to the
thickness of the seam, and UK Coal plc are using borehole and seismic data to improve the
mapping. A sandstone channel has been interpreted above 301’ s panel, and the current
problem on 301’ s face may be due to differential compaction associated with this feature.
Areas of “ possible disturbed Thick Coal” were identified on seismic surveys carried out by
British Coal, and were contacted by developments at Daw Mill, and by workings at Coventry
Mine. This gives confidence in the use of seismic surveys, and UK Coal plc are reprocessing
some of the data and also planning to carry out high resolution 3D surveys in 30’ s and 300’ s
blocks.
Within the current licence area the seam (including dirt) varies from about 6.90 m in the
north, to 6.50 m in the south. Although there are several dirt partings in the seam, the main
variation is in the parting between the Upper and Lower Nine Feet seams which thickens to
about 0.60 m in the west of 300’ s block. The parting between the Bare and Ryder seams is
often sandy and has a High frictional ignition risk.
The seam quality is generally good in zones 30 and 300E with a mined section ash of 10%
(clean coal 5%), sulphur 1.4-1.9% and chlorine 0.3%.
In the west (zone 300W) the mined section ash may increase to about 20% (clean coal 5%)
due to a thickening of the Mid Nine Feet dirt; sulphur should be 2.2% and chlorine 0.2%.
South of the present GDO boundary the seam varies from about 6.50 m in 400’ s block to
5.25 m in 500’ s. Coal quality is similar to that shown above except that the sulphur may rise
to 2.5%.
The floor of the Thick Coal is generally mudstone, but the planned extraction height leaves at
least 0.85 m of coal in the floor, and there should be no problems.
In the main reserves blocks within the GDO area (30’ s and 300’ s), the Thick Coal seam is
about 730 m-900 m below the surface. Coal Measures strata are present to the surface, and
although aquifers occur, they are not close enough to affect the workings.
4.3.3.3
Reserves/Resources Assessment
Position with regard to Reserves in 1998
The reserves/resources available at Daw Mill Colliery in 1998 were as summarised in Table
4-7. These have changed up to the last assessment in 2002 in the light of more detailed
information and a comparison will be made of the changes later in the report.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table 4-7
PAGE 42
Daw Mill Colliery Reserve/Resource Summary (01/07/98) (Source: RJB
Mining)
Million Tonnes
Seam
Reserve
Resource
Total
Mineral Potential
Thick Coal
39.300
1.202
40.502
43.128
Total
39.300
1.202
40.502
43.128
Position with regard to Reserves/Resources in 2002
The areas of the reserve blocks are similar to those in 1998, although the layout within the
blocks has been revised.
Workings in the Five Year Plan and beyond are all in 300’ s and 30’ s blocks. Mineral
Potential is shown in 400’ s and 500’ s blocks south of the current GDO boundary. The
reserve/resource is summarised in Table 4-8 below
Table 4-8
Daw Mill Colliery Reserve/Resource Summary (July 2002) (Source: UK Coal
plc)
Million Tonnes
Seam
Reserve
Resource
Total
Mineral Potential
Thick Coal
26.503
6.381
32.884
43.128
Total
26.503
6.381
32.884
43.128
Changes Between Reserve Assessments
The changes are shown in detail in Table 4-9 below.
The Proved and Probable Reserves have decreased by 12.797Mt from 39.300Mt in January
1998 to 26.503Mt in July 2002. This is due to: •
Zones 90W, 200S and most of 90W(i) have been worked.
•
Zone 30(i) has been reduced by 1.929Mt due to increase in pillar widths and reduction
from three to two panels.
•
Zone 300E has been reduced by 0.739Mt due to small layout changes.
•
Zone 300W(ii) has been downgraded from Reserves to Resources due to the risk of
faulting and the effects of seam splitting.
•
Zone 30(ii) has been downgraded from Reserves to Resources due to geological risk,
irregular shape and difficult access.
In summary, this reduction in the reserves can be quantified as shown below.
Coal worked
-4.802Mt.
Coal ‘lost’ due to layout change
-2.668Mt.
Coal downgraded from Probable Reserve to Indicated Resource
-5.327Mt.
TOTAL CHANGE
-12.797Mt.
The Measured and Indicated Resources have increased by 5.179Mt from 1.202Mt in January
1998 to 6.381Mt in July 2002 mainly by the downgrading of the reserve shown above.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 43
Mineral Potential in 400’ s and 500’ s blocks south of the current GDO boundary (Hawkhurst
Moor) remains unchanged at 43.128Mt.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 44
Table 4-9
SEAM
Thick Coal
1998
2002
RESERVE (Mt)
RESOURCE (Mt) Mineral Risk Factor Block
RESERVE (Mt)
RESOURCE (Mt) Mineral Risk Factor Block Change
or
Zone Proven Probable Measured Indicated Potential Tect Sed
Zone Proven Probable Measured Indicated Potential Tect Sed or Panel
(Mt)
Panel
(Mt)
90W 1.104
2
1
P
-1.104Mt
90Wi
2.406
3
2
P
90Wi 0.480
2
2
P
-1.926Mt
200S 1.772
2
2
P
-1.772Mt
200N
1.202
3
1
B
200N
1.168
3
2
B
-0.34Mt
30i
10.444
3
2
P
30i
8.515
3
3
P
-1.929Mt
30ii
2.004
3
2
B
30ii
1.890
3
3
B
Probable to Indicated 0.114Mt
300E 15.716
2
2
P
300E
0.097
3
5
P
Comp
301’ s panel working
300E
4.003
2
3
P
I5104C
300Ei
300E
ii
300E
iii
300W
i
300W
ii
4.338
3.429
3
4
2
2
P
P
2.570
3
2
P
3.071
3
2
P
No change
4
2
B
Whole of new 300E is
14.437Mt. (0.739Mt less
than previous 300E)
300Wi
3.071
3
2
P
300W
ii
400E
400
EL
400W
400
WL
500E
500
EL
500W
3.323
4
2
B
17.818
0.804
4
4
3
3
B
B
17.818
0.804
B
B
Same tonnage
Probable to Indicated
No Change
No Change
4.864
0.533
4
4
3
3
B
B
4.864
0.533
B
B
No Change
No Change
9.540
7.528
4
4
3
3
B
B
9.540
7.528
B
B
No Change
No Change
1.311
4
3
B
1.311
B
No Change
0.296
4
3
B
0.296
B
No Change
0.434
4
3
B
0.434
B
No Change
500
WL
500
SEL
TOTAL
Daw Mill Colliery Reserves and Resources Comparison
18.052
21.248
1.202
43.128
3.323
0.480
26.023
6.381
Reason for Change
Worked out
Almost worked out
Worked out
Minor area change
Change of panel layout
Area change difficult access
300E Block now divided into panels
Possible faulting and seam split
43.128
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
I5104C
No1 Shaft
STRATA
NG
KI
OR
LW
A
R
NE
MI
O.
D.
G.
RY
DA
UN
BO
CE
EN
/LIC
SE
LEA
200N
RY
DA
UN
BO
PARK HOUSE
Figure 4-4
285
30 (ii)
C
DE
4
200
Y
MA
180
Mudstone
BARE COAL
Sandstone
04
20
COVENTRY
WORKINGS
271
1
190
519m
522m
524m
6m
SEVEN FEET COAL
125
1
30
531m
31
(i)
0E
0
3
(i)
0W
0
3
(i)
0W
0
3
2
30
0E
30
30m
(i)
30
C
DE
(i)
30
ii)
E(
0
30
iii)
E(
0
30
Daw Mill Colliery Warwickshire Thick Seam Plan
C
DE
33
305
300E (iii)
PILLAR FOR
MERIDEN
RESERVOIRS
E
X
T
R
A
C
T
I
O
N
8
48
4
Inferior coal
BOTTOM NINE FEET/HIGH MAIN
300W(i)
284
303
304
300W(ii)
498m
50 tops
TWO YARD COAL
06
20
RYDER/ELL/TOP NINE FEET COAL
ZO
NE
283
DEPTH B.O.D.
metres
53m
50
19m
OF
C
O
MP
LE
X
282
INTERVAL
metres
386m
ARLEY WORKINGS
439m
BASE OF ETRURIAN MARL
NEWDIGATE
WORKINGS
59m
FOUR FEET COAL
ST
R
U
CT
UR
E
286
SECTION
cm
LT
AU
YF
LE
AR
20
287
ZON
EO
F
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
290
No2 Shaft
289
288
WESTE
RN BO
UNDA
RY FA
ULT
CO
MP
LEX
S
T
R
UC
TUR
E
03
20
BENCH COAL
C
DE
2
200
N
JA
05
20
E/
AS
LE
300E
comp
l
era
Min ndary
.O.
u
G.D ing Bo
rk
Wo
CE
EN
LIC
83
562m
RY
DA
UN
BO
REFERENCE
850
Depth in Metres
Boreholes
COVENTRY
WORKINGS
Seam Section in cms
C 8
C 46
W
D 7
C 53
Faults:
Proven
2.3
Projected
5
Projected from Surface Seismic
10
Fault throws shown in Metres
Proposed Workings shown
281
Existing Workings shown
Belt Conveyors
Existing
Proposed
400E
400EL
300T
Strata Bunkers
1000T
Horizontal Bunkers
12
Minimum Air Quantities
280
Booster Fans
400EL
400W
Intake Airways
Existing
Proposed
Return Airways
Existing
Proposed
279
Edged
Green
Agreed Pillars
Site of Special Scientific Interest
500E
S.S.S.I.
2002
Phasing Colour Code
2003
2004
400WL
278
2005
2006
2002
500SEL
500EL
500WL
2003
2004
2005
2006
95 R
301 R
31 R
302 R
277
500W
500E
276
UK COAL MINING LTD.
DAW MILL COLLIERY
WARWICKSHIRE THICK SEAM
RECOVERABLE RESERVES
DATE AUGUST 2002
REFERENCE:- FY/AUG-5YR2002
423
424
425
426
427
428
429
430
431
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
275
NOT TO SCALE
500
0
1000m
PAGE 45
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.3.3.4
PAGE 46
Exploration
The main reserve area, 30’ s and 300’ s was explored by surface boreholes and seismic surveys
prior to 1994, and the larger scale geological structure established. The fault resolution was
thought to be down to 5m throw, and a number of “ anomalous” seismic areas were also
identified. Several of these have subsequently been contacted underground, and although the
Thick Coal was disturbed in these areas, the exact nature is uncertain. Some of them, at least,
could be thrust faulting associated with the seam.
The recent disturbance on 301’ s face is close to one of the “ anomalous” areas, but outside the
area interpreted from the seismic. As a result more detailed investigations have been carried
out by UK Coal plc including underground seismic surveys and boreholes. A 3D surface
seismic survey is currently being carried out to investigate 30’ s area, and further surveys are
proposed for the remainder of Zone 300E. Two surface boreholes in the west have been
recommended, to investigate seam thickness and depth.
A continuing programme of inseam seismic surveys is proposed as sites become available.
4.3.3.5
Other Seams of Interest
There are no other seams of workable thickness or quality above or below the Thick Coal.
4.3.3.6
Geological and Reserve/Resource Conclusions for Daw Mill
The reserves shown in zones 30 and 300E are not considered to be entirely secure, because of
the risk of disturbed coal. The southern end of 31’ s panel (in the 30’ s block) appears most at
risk if the area of seam disturbance extends beyond the position currently shown.
The level of geological proving reduces to the west, and in Zone 300W the Mid Nine Feet dirt
parting may be 0.30m to 0.60m thick, thus reducing the vend.
These risks are being addressed by UK Coal plc.
To the south of the current GDO boundary is an extensive area of Thick Coal that was
associated with the proposed Hawkhurst Moor Mine. The level of geological proving is such
that the inclusion of zones 400 and 500 as Mineral Potential is justified, but the method of
access from Daw Mill requires consideration. If access is feasible, further surface seismic and
boreholes would be required to upgrade the resources to reserves.
4.3.3.7
IMC Commentary on the Reserve/Resource for Daw Mill
The reserves resources shown at Daw Mill are defined by UK Coal plc within the criteria
established by the reserve assessment procedure.
However, 301’ s panel when headed out was reported as showing no indication of any
anomalous structures in the roadways or face headings and was therefore expected to be free
of geological risk. This did not prove to be the case as the anomalous structures and
disturbances to the seam were only seen within the limits of the panel as production
commenced.
In the light of this, IMC regard the main geological uncertainty in the 30/300 blocks as being
the potential for possible further disturbances/possible thrust faults, (expressed as “ anomalous
seam areas” ). Most of these disturbances would adversely affect mined sections in the order
of 5m. However, IMC have for the present maintained the reserves at 26.023Mt, which is inline with the UK Coal plc Reserve Appraisal of July 2002. It should be noted that this level
of reserve is dependent upon positive confirmation from the surface seismic exploration
surveys planned for 2003. The underground exploration methods previously employed are
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 47
not considered totally conclusive in determining abnormal areas similar to that found in
operating 301’ s in 2002.
Finally, since the reserve assessment was completed in July 2002, the proved reserve in block
90W(i) has been extracted and is shown as being deleted in Table 4-10 below.
Taking the above comments into consideration, the table below indicates a summary of IMC’ s
assessment of the reserve/resources at the mine.
Table 4-10
IMC Reassessment of Daw Mill Reserve/Resource Summary (01/12/02)
Million Tonnes
Seam
Reserve
Resource
Total
Mineral Potential
Thick Coal
26.023
6.381
32.404
43.128
Total
26.023
6.381
32.404
43.128
4.3.4
MINE CHARACTERISTICS AND CONSTRAINTS
Previously, Daw Mill operated a single retreat face extracting some 4m of coal. On the first
face, 301’ s, in the new production area, an entirely new set of face equipment has been
installed. This equipment includes 2-Leg Forward Walkway, IFS Shield Supports designed to
work in face heights of 5m extraction.
Unfortunately the first face, 301’ s has been adversely affected by localised thinning of the
seam. Although reported as not apparent on the face start position, adverse geological
conditions have been present within the face panel. Several exploration techniques, including
longhole drilling have been applied to determine the extent of the abnormalities. Early in 2003
it is intended to complete a 3D seismic survey across the east section of the mine (30’ s Area)
to determine where any further abnormalities may be present.
The mine has had to cope with some extremely difficult conditions through 2002. It would
appear that conditions are now steadily improving on 301’ s face line and an increase in
production is anticipated. If this is the case then apart from accommodating a known fault of
some 3m throw, prospects for 2003 should rapidly improve.
Accepting that the mine has had to cope with the problems associated with 301’ s, at October
2002 total development drivage was only 924m. UK Coal plc has recognised this shortfall and
is planning to operate with three development teams. One of these teams will be used to
develop 302’ s main gate and prove the fault.
Observations made in both 301’ s main and return gate indicate satisfactory conditions
throughout. A dense pattern of bolting has been used in both roof and ribsides. The
characteristic weakness of the ‘Bare Coal’ (one of the seven seams), which lies almost
centrally within the overall seam section, is evident in the ribsides. Whilst movement has
occurred in the ribsides control has been maintained with extensive rib bolting. Potential
problems with further movements with the floor and ribsides would appear to be manageable
as the face retreats. It is worth noting, that by the time the face reaches its finishing position,
this section of roadway will have been in existence for a period in excess of four years.
Perhaps the biggest challenge for the mine in roadway drivage is the formation of the wide
face headings. These headings are up to 10m in width. Experience has shown that whilst
stability of the roof has been maintained the wide roadway is subjected to excessive floor lift;
two floor ‘dints’ were required on 301’ s before face equipment could be installed. Some of
the difficulties are highlighted in the fact that the mine is planning 6 months for an inter-face
transfer of equipment to the new face. Because of this, proposals have been made by UK
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 48
Coal plc to procure a second set of face equipment to maintain continuity of production. This
represents a significant single investment of some £21M. The decision to proceed with this
investment may be dependent on the mine first achieving improved production levels from
301’ s and favourable results from the 3D seismic survey over 31’ s area.
Some of the workings in the new production area are in excess of 8km from the shafts.
Consequently, travelling times are lengthy with ‘machine available time’ on 301’ s face
estimated at only 280 minutes resulting in low machine utilisation during the working shift.
The mine is addressing this problem in a number of ways. Two-way manriding conveyors are
being installed in all main gates and a new FSV manriding transporter has been procured for
trials in servicing the inbye workings. Although limited, due to gradients, an assessment will
be made of what options can be taken to increase the speed of the existing locomotive haulage
system.
A present capital scheme is in place to increase the capacity of the surface drift conveyors
from 800 to 1200t/hr which involves fitting new gearboxes and variable speed motors. It is
also thought possible that capacities could be raised still further to 1500t/hr. The surface
stocking area is limited and when the planned outputs are reached efforts are to be directed at
maximising discharge rates to the Merry-Go-Round trains and maintaining satisfactory
numbers of train journeys from EWS.
Longer-term proposals to extend the present licence area south of the existing GDO boundary
will require major capital expenditure and planning permission. Allowance for sufficient time
to gain the necessary licence and approvals will be required. It is likely that further detailed
exploration will be required to prove the reserve base before such a scheme could be
progressed. This project would include the sinking of a new shaft and the development of
new infrastructure roads. Public reactions could well prove adverse and gaining general
acceptance in the locality may prove formidable.
4.3.4.1
Ventilation
Whilst the Warwickshire Thick Coal has a low in-seam gas content (approximately 1.4m3/t to
2.0m3/t) it can present some local problems. The ventilation normally available on production
faces has been historically low due to the very high risk from spontaneous combustion.
The geographical size of the mine coupled with restrictions at the pit bottom and drift area has
resulted in the introduction of underground booster fans. This has allowed the increase in
airflow on production and development units to satisfy environmental concerns. It is expected
that the roadway configuration (with only a single return inbye of 200’ s Area and loss of
cross-section in 20’ s old gate roadways) will give rise to difficulties with operations working
300’ s Area. Whilst the uprating of booster fans may alleviate some of these potential
problems in the longer term, the ventilation system will require significant investment to
resolve potential future problems.
Faces to be worked within 300’ s Area have ventilation circuits which are in excess of 6,000m
in total length, coupled with face runs in excess of 2,600m. This will present environmental
problems associated with heat, humidity, methane and potentially spontaneous combustion.
The mine utilises nitrogen gas, which is injected into the area behind the working face (at
present 301’ s) at a rate of 10m3/min to reduce the spontaneous combustion risk. This nitrogen
is produced on the surface of the mine by a ‘Pressure Swing Absorption’ system.
4.3.4.2
Subsidence
Reserve Zone 300E, 30(i): The five-year development plan shows that 301’ s is currently
working in area 300E with 31’ s and 32’ s shown to work in area 30(i).
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 49
31’ s and 32’ s will affect Corley Moor village, otherwise there are only isolated buildings in
this area. The M6 Motorway may be affected to a slight extent by the panels, 31’ s would
affect the Pickford Beck. In addition, a large water main crosses the area.
Subsidence damage costs are low and estimated to be in the region of 15 pence/t.
Reserve Zone 300E (i) to 300E (iii) and 300W (i) to 300W (iii): 302’ s to 305’ s panels are
shown planned in these areas but they are not yet included in the Five-Year development plan.
These areas are a mixture of agricultural and wooded land. A pillar of support has been left
around the sensitive Meriden Reservoirs. The A45 trunk road will be slightly affected, as will
a major oil pipeline.
Subsidence damage costs are again low and estimated to be some 15 pence/t.
Reserve Zone 200N: This is a rural area with Fillongley village at its eastern end, Fillongley
Hall lies to the west edge of the area.
Subsidence damage costs are higher and likely to be in the order of 60 pence/t if the
underground layout comes within influencing distance of the village.
Reserve Zone 30 (ii): The villages of Corley and Corley Moor would be affected by mining
in this area. Of greatest significance, however, is the M6 Motorway, which crosses the
northern end of this area. Subsidence damage costs are likely to be high at £3 to £4/t.
Reserve Zone 300W (ii):
The town of Meriden lies at the western edge of this area and
many houses and other structures will be affected. The A45 trunk road crosses the centre of
the area. Subsidence damage costs have been estimated to be in the order of 50pence/t.
Reserve Zones 400 and 500(Coventry and Hawkhurst Moor Areas): Most
of
the
Coventry/Hawkhurst Moor area is subjected to estimated subsidence damage costs of less that
£1/t. The exception is in the south east, which includes the outskirts of Coventry and the
Birmingham/Coventry railway line. Underground longwall layouts could be heavily
constrained in and adjacent to these built-up areas. Indeed in some cases, mining could be
precluded on the grounds of excessive costs.
4.3.4.3
Coal Preparation Facilities
Daw Mill Colliery has a coal preparation plant rated at 800t/h, equating to around 80,000t/w
or 3.84Mt/a. The quality of the ROM allows the operation to be based on dry fines extraction
for the PSF market and a large coal dense medium plant to satisfy the domestic market.
4.3.5
4.3.5.1
HISTORIC PERFORMANCE
Production
Table 4-11
I5104C
Historical Production Performance at Daw Mill
Daw Mill
1999
2000
2001
Actual Output
million tonnes – saleable
1.457
1.909
1.222
Budgeted Output
million tonnes - saleable
1.900
1.800
1.800
Difference
million tonnes - saleable
-0.443
+0.109
-0.578
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 50
Production in the latter part of 1999 was adversely affected by a protracted face change and
slow start of the replacement panel. Output in 2001 was limited to 1.222Mt due to 95’ s face
being badly affected by adverse geology. Production in 2002 saw the introduction of the first
5m-extraction face in the southern block, 301’ s. Output should have built up to approaching
80,000t/w. In the event the geological disturbance that has been encountered has limited
production to only around 4,000t/w.
4.3.5.2
Development
Table 4-12
Historical Development Performance at Daw Mill
Daw Mill
1999
2000
2001
Actual Developments
metres
4,408
1,909
1,222
Budgeted Developments
metres
4,820
5,005
3,810
Difference
Metres
-412
-3096
-2,588
There has been a considerable shortfall in development progress during the period 2000-2001.
Significant difficulty was experienced in the installation of 301’ s during the latter part of 2001
and early 2002, which impinged on roadway drivage. Developments have also been held in
abeyance whilst efforts have been concentrated on overcoming the difficulties experienced on
301’ s face.
4.3.6
FUTURE MINING PROJECTION
The mine’ s business strategy is to consolidate production from mid 2003 onwards at around
3.4Mt/a in the current working area, working a single retreat face extracting a 5m working
section of Warwickshire Thick Coal. The plan includes the procurement of a second set of
thick seam extraction equipment to eliminate production gaps and ensure continuity of
production.
The proposed layout contains seven faces that have been standardised at 295m wide, other
than for two panels that have reduced dimensions due to the confines of the expected
geological structure and surface features. Assuming that all the faces are worked to the
dimensions shown then sufficient coal should be available to maintain production at the rate
of 3.4Mt/a for around 8.4 years. This will result in cessation of production at the mine in mid
2010. There are no firm plans in place at present to extend the life of the mine beyond 2010.
4.3.7
4.3.7.1
PRODUCTION AND DEVELOPMENT FORECASTS
Production
The Draft Five-Year schedule is as follows:
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table 4-13
Face
Tonnes
in Panel
PAGE 51
Five-Year schedule
2002
2003
2004
2005
2006
Development (metres)
1,022
3,417
3,274
5,098
5,714
Total Output (Mt)
0.734
1.394
3.450
3.402
3.171
95
301
4,996,000
31
4,540,000
302
3,771,000
Operating a single retreat face with an extracted height of around 3.9m the mine has averaged
around 1.74Mt/a for the period 1995-2000. Production has exceeded 1.9Mt on three
occasions and surpassed 2Mt in 1997. However, in 2001 output was limited to 1.22Mt due to
95’ s Face production being badly affected by adverse geology. 95’ s unit was replaced in
April 2002 by the first face in the new southern block, 301’ s, that has been installed with
equipment capable of extracting a working section of 5m.
It was anticipated that with the introduction of 301’ s, with its increased working section, that
output would build to over 79,000t/w, which (working three shifts per day) is equivalent to
around 2.8 shears per shift. This resulted in a projected output for 2002 of 2.847Mt. In the
event 301’ s has been very badly affected by a localised seam thinning caused by changes in
both the roof and floor strata replacing seam. This has resulted in roof control problems and
the formation of cavities, which have required filling. Production has therefore been limited
for a protracted period of time to only 4,000t/w (2 shears). Output for 2002 is therefore
projected to be only around 734,000t, which is over 2.1Mt less than that budgeted.
301’ s face will traverse a 2.9m upthrow fault that lies some 220m from its present position.
In preparing the new Draft Five Year Plan, UK Coal plc has taken cognisance of the recent
difficulties and assumed a weekly production rate of only 4,000t from its present position
through until it has fully traversed the fault. At this rate it will be June 2003 before the face
starts to increase production, finally improving to 71,000t/w by November 2003. This results
in an annual output of only 1.4Mt.
Since the Draft Five Year Plan was prepared in October, adverse geological conditions on
301’ s face have eased and performances have started to improve, around 11,000t produced in
the first week of December. In light of this UK Coal plc may re-evaluate their plans with a
view to substantially increasing the proposed output for 2003.
As in the case of 301’ s, the following planned faces are generally 295m long and with a 5.0m
extraction yield around 1,900t/m. The exceptions are 302’ s face, which due to the confines of
faulting proven by surface seismic is planned to be 265m in length and 304’ s which is
planned at 230m to avoid entering the pillar for Meriden Reservoirs. With face runs of up to
2,800 m the seven panels planned contain on average around 4.4Mt each, giving long life and
minimum interruption to production through face changes.
It is important to note that the draft programme shows the utilisation of two sets of 5mextraction face equipment to ensure face continuity. This will require the procurement of a
second set of equipment in 2004 for installation on 31’ s Face, which lies to the east of 301’ s
beyond a 5m fault. Some £21M has therefore been included within the draft five-year
investment programme for 31’ s face mechanisation.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 52
The Draft Five Year programme visualises production being raised to around 3.4Mt in 2004
and 2005 and then declining to around 3.17Mt in 2006 with the working of the shorter 302’ s
Face. Stripping levels are maintained at around 2.5 per shift (7.5 per day) with an effective
web depth of 1m. Such is the extent of the proposed panels that only three face changes take
place in the five year period to the end of 2007.
Due to the uncertainty created by the unexpected geological conditions encountered on 301’ s
face, plans now include a 3D surface seismic survey to try and identify any similar areas and
their extent. The first survey of 31’ s/32’ s area to the east of 301’ s has already been
commissioned. Further surveys will also be undertaken to the west to prove 302’ s and
subsequent faces.
From experience it is known that face installations can take some six months to complete, so a
second set of face equipment is necessary to avoid protracted production gaps. Alternative
strategies are currently being examined by UK Coal plc including the provisioning of 3.5m
extraction equipment sourced from elsewhere within the Company. The results of the seismic
surveys will be crucial in determining the face design of subsequent faces, as will the
performance of 301’ s once it is clear of the geologically disturbed area.
4.3.7.2
Developments
The Draft Five Year Plan shows the annual development requirement being between 3,274m
in 2004 and 5,714m in 2006. Three heading teams are shown predominantly throughout the
plan.
31’ s tailgate has completed over 1,100m, however, the drivage has been temporarily stopped
and repairs undertaken mainly in the form of roadway dint. The initial 450m of the Coal Gate
has also been completed and the main drivage is now being set up. As with all gate roads
both roadways use roof bolts as the primary means of support and are driven with ED158
Bolter Miner heading machines. The Coal Gate is phased at 65m/w and the Tail Gate at
72m/w.
The main lateral trunk roads to the west have progressed forward, recently completing the
circuit for 302’ s development. The Draft Five Year Plan shows the start of 302’ s
development being delayed until June 2003. However, it is understood that the decision has
recently been made to bring this forward giving new impetuous to progressing 302’ s Coal
Gate forward ahead of the Tail Gate to prove the position of faulting that is expected to
eventually encroach from the west.
Normally bolted gate roads are phased at 60m/w and arched main roads at 25m/w. Face
headings, which are driven at 10m wide, are phased at 36m/w. These rates are all based on
those previously achieved.
4.3.7.3
Risk
The unexpected localised geological features that have seriously affected 301’ s since its
inception in the early part of 2002 are a cause of major concern. Similar areas of geologically
disturbed ground were encountered at the nearby Coventry Colliery and it is possible that
further localised pockets could affect future panels. It is hoped that 3D surface seismic
surveys will be able to identify any similar areas and the mining plans amended accordingly.
It is expected that a seam split will develop to the south-west potentially affecting 304’ s and
305’ s panels; which may preclude 5m extraction. It is intended to drill surface boreholes to
determine the position and extent of the split prior to the faces being developed and worked.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 53
The development schedule only utilises 3 development teams resulting in gate road drivages
being phased at rates of up to 72m/w (31’ s Tail Gate). In many instances the gate road
developments approach 3km in length, It may become difficult to sustain such high average
drivage rates as ventilating and servicing the headings over such protracted lengths may
become restrictive to development performance. As previously stated the Warwickshire
Thick Coal oxidises quite readily and is, therefore, prone to spontaneous combustion.
Similarly, the oxidisation process can cause some problems with CO levels that could affect
drivages.
The colliery has in place the infrastructure to facilitate mining at the rate of 3.4Mt/a, however
the mine site has comparatively limited stocking room. The planned output is therefore
reliant on ensuring that sufficient trains are maintained at all times. Delays on the rail
network and availability of rolling stock and locomotives outside the control of UK Coal plc
could therefore potentially interrupt production.
4.3.7.4
Long Term Plans
The current plans do not include the development of areas beyond those being worked. There
are significant blocks of coal to the south of the current area, however, they are remote from
the existing mine entries and at significant depth. It has long been recognised that, for Daw
Mill to exploit this mineral potential, the sinking of a satellite shaft from the surface would be
necessary to provide ventilation and man and materials access.
UK Coal plc have alluded to the potential for a shaft and indicated that costs would probably
be in the order of £110M. However, as at this time no formal scheme has been prepared or
financially evaluated. A suitable site for the shaft has not been formally identified and no
underground layout plans for the extension of the present infrastructure have been prepared.
Assuming that the mine does achieve its planned production level of 3.4Mt/a then the shaft
and all the necessary infrastructure work would have to be completed to enable the first face
to be in production by mid 2010 at the latest to ensure continuity of production. It is IMC’ s
opinion that it is highly unlikely that a scheme could be prepared and the necessary planning
permissions put in place in time to enable the works to be undertaken and completed within
the next 8.5 years unless UK Coal plc starts the planning process almost immediately.
4.3.8
OPPORTUNITIES FOR FURTHER INVESTMENT
Currently experiencing probably the worst financial period of its recent life, this mine has
clear potential to generate cash and has a track record of profits other than in the last two
years. 2002 is particularly bad and 2003 probably underestimates the performance. It is
therefore difficult to estimate cash generation and it is patently wrong to use the current
estimate for 2003. However, based upon past performance and allowing for an increase in
performance into the next year as the planned face operates satisfactorily, a cash generation of
some £10M/annum could be assumed, as was previously achieved in 2000. With a project of
five years this requires constantly generated sums of £40M and a total project sum of about
£60M.
Daw Mill is currently leasing a set of face equipment which also indicates potential for this
form of funding. It has a generally good track record of profitable operations and also, despite
the current difficulties, a track record of successful project delivery.
At an investment of such levels however, additional income would have to be £15M for five
years or £10M for nine years. This would represent a considerable challenge over and above
the current plans. If the potential from the current face can be realised then generating the
levels of cash through the required number of years could be possible.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 54
If conditions on 301’ s significantly improve and output is raised towards design capacity of
the face, then the mine will move rapidly into operating profit. However, until this
improvement is realised it will be difficult for UK Coal plc to take decisions on implementing
long-term investment schemes. IMC is of the opinion that the UK Coal plc forecasts for
output at Daw Mill in 2003 is over cautious. Certainly the resultant estimated losses from this
forecast give very limited encouragement to implement future investment.
Assuming that sufficient cash is generated over future years to support some of the more
limited schemes previously referred to in the above, then UK Coal plc may decide on the
long-term future for the mine. Supporting a major scheme to continue production beyond the
present working area will require high levels of capital expenditure and long lead times.
The feasibility of a scheme for access, development and production from the
Coventry/Hawkhurst Moor area is beyond the scope of this report. Although future prospects
for deep mine coal production are at present low, UK Coal plc has little time in which to make
a decision on implementing such a scheme.
Due to the unexpected geological conditions encountered on 301’ s face, exploration has taken
precedence within the mine’ s investment programme. 3D surface seismic surveys are to be
employed in an attempt to identify any similar areas of disturbed ground and their extent. The
first survey of 31’ s / 32’ s area to the east of 301’ s has already been commissioned at a cost of
about £1M and can be regarded as Category 1. Further surveys will also require to be
undertaken to the west to prove 302’ s and subsequent faces. This also requires to be
supplemented by surface boreholes that are needed to establish the position of an expected
seam split to the west of the proposed take. This further exploratory work estimated to cost
around £1.5 – 2.0M could be regarded as Category 2.
An integral part of the mine plan is the procurement of a second set of 5m-extraction face
equipment to avoid production gaps and maximise output. The viability of this scheme could
be dependent upon successful operation of the current face once the disturbed area has been
negotiated and on the outcome of the 3D Seismic surveys as outlined above. This expenditure
should be regarded Category 1, but could qualify as Category 2 if the detailed finances
demonstrate a need for support to justify expenditure.
Other schemes include:
•
Upgrading the drift coal clearance system from 800tph to 1,200tph by the installation of
new gearboxes and variable speed motors
•
Improvement to man-riding and hence Machine Availability Time by the introduction of
free steered vehicle ‘buses’ .
•
Bunkerage improvements and stocking ground increase.
In addition the westerly extension of the main lateral roadways could be capitalised as longlife strategic developments.
For the longer-term it is recognised that, for Daw Mill to exploit the mineral potential south of
the current working area, the sinking of a satellite shaft from the surface would be necessary
to provide ventilation and man and materials access. UK Coal plc has confirmed the potential
for a project for a shaft and associated infrastructure (both surface and underground) and that
cost would probably be in the order of £110M. However, as at this time no formal project has
been prepared or financially evaluated and therefore may be regarded as Category 3 scheme.
It must be borne in mind that if the projected production levels are achieved then the current
working area (assuming all the planned panels are realised) will reach exhaustion by mid
2010 at the latest. It is IMC’ s opinion that negotiations regarding planning permissions would
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 55
need to commence immediately to enable the physical works to be undertaken and completed
within the next 8.5 years. It is also important to note that the current mine layout does not
include for entry into the Coventry/Hawkhurst Moor Area.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.4
ELLINGTON COLLIERY
4.4.1
BRIEF DESCRIPTION OF SITE
PAGE 56
Ellington is located in the county of Northumberland with the principal site (Ellington North)
situated 1.5km from the east coast and 27km north of Newcastle-upon-Tyne. The main
administration buildings are situated on this site and it is the main access point for manriding
into the mine. The site is about 1km from the A1068 main road.
Ellington Colliery (established in 1909) was combined with Lynemouth Colliery, (established
in 1927) in 1983 this created the Ellington combine. The Bewick Drift, established in 1966,
and the coal preparation plant at Lynemouth were retained for handling the output from the
combine. Ellington surface facilities are now divided into three main sites, known as
Ellington North, Bewick Drift and Ellington South, the site of the coal preparation plant.
The Bewick Drift lies adjacent to the coast approximately 1.5km east of Ellington North. The
mine access is used for materials transport and also contains the mineral conveyor. From the
drift an overland conveyor some 1km in length takes the mineral to the coal preparation area.
Sited near to the drift are the No.3 and No.4 shafts, which are used for ventilation, and in the
case of No.4 shaft, also for pumping.
Ellington South, where the coal preparation facilities are sited, is also adjacent to the coast
some 1.5km southeast of Ellington North.
Since the mine started production six seams have been worked but in latter years workings
have been confined to the Main, Yard and Brass Thill seams. Because of workings being
undersea and with limited cover to the seabed, a combination of longwall and room and pillar
workings has been necessary.
On 12 February 1994 British Coal ceased production at Ellington and the mine was placed on
care and maintenance. RJB Mining (later to become UK Coal plc) took over the mine in
January 1995 and production recommenced with initial workings in the thin Brass Thill seam
whilst work was completed accessing the thicker Yard seam.
4.4.2
MINE BOUNDARIES, OTHER SURFACE CONSTRAINTS AND ISSUES
Ellington is connected to a number of abandoned mines, the only significance being limited
flow of water. The licence boundary to the south is adjacent to the Lynemouth old workings.
It is possible that the present limits will require slight modifications to facilitate the planned
layout for future longwalls. To the east the Brass Thill Seam becomes unworkable and to the
north by the limiting travel distances.
The area of partial extraction in the Main Seam to the north is limited by undersea mandatory
regulations and follows 60m contour of depth below sea bed.
4.4.3
GEOLOGICAL ASSESSMENT OF THE MINE
The mine is located on the Northumberland coast, in the Northeast Coalfield, some 27 km
north of Newcastle on Tyne. The mine was combined with the adjacent Lynemouth Colliery,
and the workings are all offshore. The operational area is limited by old workings to the
south, seam deterioration to the west, reduced cover beneath the sea bed in some seams, and
to the north by distance from the shafts.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.4.3.1
PAGE 57
Structure
The structure is known from extensive workings in several seams, and also to a lesser extent
from offshore boreholes and seismic surveys. The seam dips are generally to the south and
southeast. The area is crossed by a number of large faults, some of which are associated with
igneous intrusions. The most relevant are the Causey Park Dyke and the Acklington Dyke
about 8 km north of the shafts. Minor faulting is common within the mining areas.
4.4.3.2
Seams in Reserves
The following seams are considered to be in the reserve classification for this colliery:
•
Main Seam (F)
•
Yard Seam (G), worked out since the present 2002 reserve assessment was completed.
•
Brass Thill Seam (K)
Seam Characteristics
Main Seam (F)
Limited information indicates that the roof contains erosive sandstones that may affect the
seam in the east. The seam is variable with several dirt partings. In the west the overlying
High Main (E) Seam is combined, but this splits away to the east. The seam thickness is
shown in the reserves as 3.28-3.50 m, including 0.50-1.50 m of dirt.
As mined ash
23-44%
Clean coal ash
6%
Sulphur
1.5%
Chlorine
0.2%
The floor measures are variable as the underlying Yard Seam (G) splits away in some parts.
Where the interval is less than 3 m, weak mudstones may be present.
The Main Seam (F) proposed workings are limited to the north by the 60 m cover line to the
sea bed.
Yard Seam (G)
In the remaining area the overlying F seam converges on the Yard Seam (G).
This is a complex seam with several dirt partings. Details have not been included as this seam
is now worked out. However for completeness the quality of the seam is shown below.
As mined ash
19%
Clean coal ash
12%
Sulphur
1.7%
Chlorine
0.2%
No data is included on the floor, as this seam has now been worked out.
Brass Thill Seam (K)
The Brass Thill (K) is in some parts combined with the overlying J Seam. The early part of
311’ s panel may have roof problems due to the splitting away of the J seam. The southern
faces, 32 to 38, are expected to have a thick sandstone close above the seam, and this will
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 58
give hard cutting conditions in faulted areas. Roof problems may also occur if the sandstone
locally lifts off, the weak intervening strata, falling away.
Seam splits occur and the section contains several dirt bands. At the start of 311’ s panel the J
seam is also present and the seam is shown as 2.67m. Only 1.82m is extracted, and this
includes 0.32 m of dirt. As this seam splits away, the section is reduced to 1.33m including
0.09 m of dirt. Underground boreholes adjacent to the old Lynemouth workings in the south
suggest a thicker section of 1.48-1.68 m.
As mined ash
15-30%
Clean coal ash
9-12%
Sulphur
1.5-3.05%
Chlorine
0.1%
Output is largely to the adjacent Alcan works to the south of the mine. Comments have been
made concerning the poor Ash Fusion characteristics of this seam in relation to the Alcan
specification, but it is understood that blending with the Main seam will resolve this.
The floor is generally up to 0.60 m of weak mudstone overlying strong siltstone/sandstone,
which may result in hard cutting even through small faults.
4.4.3.3
Reserves/Resources Assessment
Three seams are shown in the assessment. These are: High Main (E) and Main Seam (F)
Areas of the High Main (E) and Main (F) seams north of the Causey Park Dyke have been
abandoned and the access in the Brass Thill (K) closed. Two areas, 5W and 5E, in the Main
Seam are to be worked by partial extraction within the 5 year plan.
Yard G
In the Yard Seam, areas north of the Causey Park Dyke have been abandoned. Remnant coal
is shown in the July 2002 Reserves Assessment but these reserves have now been worked out.
Brass Thill (K)
The area north of the Causey Park Dyke was accessed by development roadways, but the
seam had been heat-affected over a large area by igneous intrusions. As a result the
development was abandoned and the roadways have been sealed off. The remaining reserves
are in the southern part of the mine and some are adjacent to old workings from Lynemouth
mine.
Position with regard to Reserves in 1998
The reserves/resource available at Ellington in 1998 were as summarised in Table 4-14 below
based on the knowledge at that time. These have changed up to the last assessment in 2002 in
the light of more detailed information and a comparison will be made of the changes later in
the report.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table 4-14
PAGE 59
Ellington Colliery Reserve/Resource Summary (01/07/98) (Source: RJB Mining)
Million Tonnes
Seam
Reserve
High Main E
Resource
Total
1.578
1.578
High Main/Main E/F
0.421
Yard G
1.158
1.461
2.619
Brass Thill K
1.255
5.361
6.616
Mineral Potential
0.421
0.268
Plessey M
1.741
Total
2.834
8.400
11.234
2.009
Position with regard to Reserves/Resources in 2002
In the 2002 reserve assessment only three seams remain. These are summarised below in
Table 4-15 below although since July all remaining tonnage in the Yard Seam have now been
worked.
Table 4-15
Ellington Colliery Reserve/Resource Summary (July 2002) (Source: UK Coal
plc)
Million Tonnes
Seam
Reserve
Main F
0.618
0.618
Yard G
0.034
0.034
Brass Thill K
2.616
2.616
0.274
Total
3.268
3.268
0.274
I5104C
Resource
Total
Mineral Potential
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 60
Table 4-16
SEAM
Zone
High Main
High
Main/Main
Yard
Brass Thill
Plessey
TOTAL
I5104C
6
2
1998
RESERVE (Mt)
RESOURCE (Mt) Mineral Risk Factor Block
or
Proven Probable Measured Indicated Potential Tect Sed
Zone
(Mt)
Panel
1.578
5
5
B
0.026
3
2
B
5W
5E
0.257
0.138
3
3
4
5
P
P
5NW
5NE
5SW
5SCN
5SC
5SE
6W
6E
1N
1S
2W
2WE
2WE1
2WE2
0.116
0.164
0.197
3
3
3
2
2
2
5
5
3
3
2
3
3
3
4
3
4
2
2
2
5
5
3
3
2
2
2
3
P[
P
P
P
P
P
B
B
p
P
P
P
p
p
3
1
4
4
4
5
5
3
5
3
1
4
4
4
5
5
4
5
p
P
P
p
P
P
B
B
B
2WS
2E
6SW
6SC
6SE
6NW
6NE
5.1
6.1
0.043
0.194
0.444
0.540
0.921
1.045
0.268
0.588
0.856
0.251
0.376
0.705
0.093
0.182
0.142
0.250
0.476
1.652
0.690
1.051
1.362
1.472
1.107
7.293
2.009
Ellington Colliery Reserves and Resources Comparison
2002
RESERVE (Mt)
RESOURCE (Mt) Mineral Risk Factor Block Change
Proven Probable Measured Indicated Potential Tect Sed or Panel
(Mt)
-1.578
-0.026
5W
5E
5S
5SCN
5SC
0.313
0.228
0.077
0.014
0.020
1N
1S
1.069
2WE
2WE1
2WE2
2WE3
2WS
0.188
0.156
0.383
0.117
0.703
0.274
0.034
3.234
3
3
3
4
5
3
p
P
P
1
2
1
2
P
3
3
3
3
p
P
2
3
3
3
3
3
3
3
3
3
P
P
P
P
p
+0.056
+0.090
+0.077
-0.116
-0.164
-0.197
-0.029
-0.174
-0.444
-0.540
-0.921
+0.024
+0.006
-0.588
-0.700
-0.095
+0.006
+0.117
-0.002
-0.753
-0.182
-0.142
-0.250
-0.470
-1.652
-0.690
-1.051
Reason for Change
Abandoned
Abandoned
Layout change
Layout change
Additional area
Worked
Worked
Abandoned
Worked
Worked
Worked
Abandoned
Abandoned
Increased area
Re calculated
Worked
Worked
Layout change
Re calculated
Additional area
Recalculated
Worked
Abandoned
Abandoned
Abandoned
Abandoned
Abandoned
Abandoned
Abandoned
0.274
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
437000
436000
435000
434000
433000
432000
431000
430000
429000
428000
426000
427000
REA
CE A
N
E
LIC
E OF
G
D
E
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
I5104C
604000
603000
HIGH
SEAM MAIN / MA
IN
S (E/F
)
ACKLINGTON DYKE
602000
EA
E AR
LEAS
9840
100/-
P.A.I. REGS 1979
9850
45m WARNING LINE
KE
K DY
PAR
SEY
CAU
601000
ED
EA B
TO S
LINE
VER
O
C
60m
160/-
5W
FM62
FM63
FM64
FM65
FM66
FM67
FM68
FM69
FM61
5E
FM611
YKE
KD
YKE
PAR
KD
EY 1979
AUS
PAR
T C REGS
Y
S
E
IN
.I.
S
AGA E) P.A
CAU
G
INE
G L N ED
RNIN ER
WA OUTH
(S
45m
FM610
600000
ACKLINGTON DYKE
13
33/-
LEASE AREA
599000
160/-
11
5S
260/-
10
12
HIGH MAIN / MAIN SEAMS (E/F)
Figure 4-5
COASTL
INE
14
11
20/-
320/-
60/-
4E
KD
598000
10
AR
EA
10
OF
LIC
EN
CE
60/-
20/-
145/-
9
13/-
ED
GE
39/-
140/-
9930
597000
9
20/-
8
7/-
9920
9910
RTH
NO
4th.
AREA OF COMPLICATED
DRIFT FILLED CHANNEL
UP TO 20M BELOW SEA BED
9900
8/ -
65/-
596000
33/90/-
8
F-K
9960
Drift
7
40/-
9940
6/-
30/-
9950
7
8/80/-
90/-
595000
11/-
9940
H
RT
NO
3rd.
9940
9950
14/-
9950
6
9960
9960
9970
6
20/-
79/-
90/-
9940
9990
435
70
99
ST
EA
1st.
9980
Ellington Colliery Main Seam “ F” Plan
34/-
9
5
594000
4
3
593000
2nd RETURN
IN YARD SEAM
GL
ATIN
ER
OP
EA
NC
ICE
REA
2
1
150T STAPLE BUNKER
592000
No. 3 SHAFT
No. 4 SHAFT
No. 1 SHAFT
No. 2 SHAFT
No. 3 SHAFT
BEWICK DRIFT
ELLINGTON COMBINE
591000
UK COAL MINING LTD
PHASING
NOTE : For sake of clarity
Continuous Miner phasing
does not show years.
2002
LONGWALL EXTRACTION SHEARERS SHOWN
ELLINGTON COMBINE
G53R
2003
PARTIAL EXTRACTION MINERS SHOWN
53
MAIN SEAM ’F’
2004
DISTANCE FROM SHAFT (KILOMETRES) SHOWN
8
RESERVE AREAS
2005
WORKINGS IN MAIN SEAM SHOWN
WORKINGS UPDATED
AUGUST 2002
SCALE
DATE OF PREPARATION
1/10000
AUGUST 2002
PLAN DATUM
10,000ft BELOW ORDNANCE DATUM
PAGE 61
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
2006
437000
436000
435000
434000
433000
432000
431000
430000
429000
428000
426000
427000
REA
CE A
N
E
LIC
E OF
EDG
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
I5104C
604000
603000
ACKLINGTON DYKE
602000
45m WARNING LINE
P.A.I. REGS 1979
601000
ACKLINGTON DYKE
9880
KE
K DY
PAR
SEY
CAU
131 /-
160/-
57
GM
C
5SCN
105 m COVER LINE TO SEABED
GM53A
G53MG
B
GM
5SC
ASE
F LE
EO N
EDG ENSIO
T
EX
260 /-
20/-
320/-
60/ -
4E
KD
598000
34/-
60/-
EA
AR
SE
EA
FL
O
GE
ED
9850
20/-
145/-
13/ -
39/ -
9840
597000
140 /-
20/-
15/ -
7/8/-
4t h.
AREA OF COMPLICATED
DRIFT FILLED CHANNEL
UP TO 20M BELOW SEA BED
26/ -
RTH
NO
65/-
596000
33/ 90/-
9850
40/-
6/ 30/ -
8/-
7
11 /-
90/-
RTH
NO
3rd.
Ellington Colliery Yard Seam “ G” Plan
AREA OF COMPLICATED
DRIFT FILLED CHANNEL
UP TO 20M BELOW SEA BED
9930
Figure 4-6
599000
52A
PA RTIAL SEAM
WASHOUT
G52R
9970
9980
160/-
LINE
OF
CTURED
CONJE STONE RO
ND
OF SA
33/-
G53R
9890
E
DYK
ARK
EY P
S
U
CA
600000
INE
RL
VE
CO BED
60m SEA
TO
E
AS
LE
OF ION
GE TENS
D
E EX
595000
14/-
6
6
20/-
79/ -
90/-
T
EAS
1st.
5
594000
4
20/-
3
A
RE
EA
NC
ICE
GL
IN
T
A
ER
OP
593000
2
1
592000
No. 3 SHAFT
No. 4 SHAFT
No. 1 SHAFT
No. 2 SHAFT
No. 3 SHAFT
BEWICK DRIFT
ELLINGTON COMBINE
591000
UK COAL MINING LTD
PHASING
NOTE : For sake of clarity
Continuous Miner phasing
does not show years.
2002
LONGWALL EXTRACTION SHEARERS SHOWN
ELLINGTON COMBINE
G53R
2003
PARTIAL EXTRACTION MINERS SHOWN
53
YARD SEAM ’G’
2004
DISTANCE FROM SHAFT (KILOMETRES) SHOWN
8
RESERVE AREAS
2005
WORKINGS IN MAIN SEAM SHOWN
2006
WORKINGS UPDATED
AUGUST 2002
SCALE
DATE OF PREPARATION
1/10000
AUGUST 2002
PAGE 62
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
PLAN DATUM
10,000ft BELOW ORDNANCE DATUM
437000
436000
435000
434000
433000
432000
431000
430000
429000
428000
427000
426000
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
I5104C
604000
1
J 2.2.2 K
EA
E AR
C
N
LICE
E OF
G
D
E
J 2.2.2 /K1 K 2.1
K1
603000
WORKINGS IN
BRASS THILL ’K’
148’
EA
AR
SE
EA
L
OF
GE
ED
ACKLINGTON DYKE
COAS
T
602000
WORKINGS IN
MAUDLIN SEAM ’H’
K1
601000
K1
J2
KE
K DY
PAR
SEY
CAU
Y
LE
IL
SW
EY
ILL
SW
K1.2
J
K1
2.2.2
K1
K1
J 2.2.2 K 1 K 2.1
J2 K
ACKLINGTON DYKE
131’
J 2 K 1 K 2.1
33/50/-
YKE
KD
PAR
SEY
CAU
20/-
J2 K
12
+1m
160/-
2/-
TO SEA
BED
5/-
KE3
7/-
60
m
K64
FS+
KN62
FS
9520
420’
K.66
K.65
1/6
7/-
13
11/6
4/-
6/-
5/-
J2.2.2 K 1
12
11
J 2.2
+12/-
3rd. NORTH
420’
36/-
24/-
10
5m
K1
KD6E
KW5
2
437
CO
VE
R
1/6
KE2
FS
2/-
14
2/6
8/-
11
KW6
J
7/-
6/-
PR
O JE
CTE
D
599000
K.651
10/+20/-
11/-
33/-
EY
ILL
SW
D
BE
600
1/-
EY
ILL
SW
E
R LIN
VE
CO
K61
7/-
J2. K
K91
K1
+8/-
J 2K
1
K9
598000
10/-
4/-
4E
KD
7
K4
11
7
K1
3/- 952 0
4/-
4/6
4/-
5/3
5/WN
1/6
32/-
6/-
8
K1
WA
145/-
OU
T
3/-
3
KW
12
K.2
2E16
K2
SW
ILL
EY
5/-
61
K.2
K321
50/-
10
K.2
5/4/-
5/7
9
14
K.2
5/-
3/-
SH
62
K.2
4/6
9
+8/-
5/-
F.S.
5
K1
4
K.1
K J 2.2 K
K1
8/-
TH
ROW
15/-
7/-(F)
5/-(F)
10
1/-
4/-
597
6/-
5/6
140/-
8/-
5
K.2
6
K.2
1/-
ST
EA
93
00
4/-
1/-
4/6
310
KS
1/-
2/6
9
1/-
10/- to 20/(Levels) 1/-
2/-
4/-
31
1
3/2/1/-
6/-
ST
EA 5/-
2/6
1st.
3/-
5/4/-
2/6
2/3
6/6
4/6
5/5/6
4/-
4/6
4/-
rth
No
9240
2WE
32
KS
6/-
4/6
8/- =
2/6
2/6
1/3
1/-
1/-
6/-
4
2/9
12/-
KS 33
10/ -+
U/ K
2/-
5/-
90/-
2WS
5/6
1/-
10/ -
8/-
1/-
4/6
3/-
7/8/-
LIT
SP
2/6
1/-
2/-
593
43 4
43 3
3/-
LINE
432
6/6
37m WARNING
E
1979
P.A.I. REGS
LIN
2/-
1/6
2/2/-
6/3/4/3/-
2/6
6/1/-
H COLLIERY
LYNEMOUT L WORKINGS
BRASS THIL
C&B 64"
1/1/-
1/
1/6
KS 38
3/3
2/6
3/-
2/-
1/6
2/6
1/6
3/-
IERY
TH COLL
LYNEMOU L WORKINGS
BRASS THIL
5/7/2/-
3/8
2/-
3/-
6/-
5/-
KS 37
1S
2/-
593
3/6
4/-
1/-
1/6
6/6
2/-
3/6
1/3/-
KS 36
2/6
19/-
4/-
2/6
Est. 10/-
3/4/-
19/-
7/-
3/-
2/6
14/-
7/-
2/6
1/-
1N
1/-
2
3/6
1/6/-
2/-
1/-
C&B 66"
4/-
1/6
5/4/2/-
9
1/6
2/6
3/-
3/2/-
1/-
7/-
20/-
2nd RETURN
IN YARD SEAM
10
3/-
594
3/6/-
3/-
2/-
4/-
2/-
2/-
5/-
5/-
5/-
2/-
9
1/6
2/6
1/-
OF
LE
AS
E
4/-
4/-
3/-
1/6
5/-
KS 35
3
Est. 40/4/4
U/K
Not Proved (Large)
U/ K
ED
GE
1/4
2/6
KS 34
8/-
8
?
2/6
6/-
2/6
90/-
9
70/ -
29/-
-/6
4/-
5/-
2/-
U/K
2/6
8
4/-
2/-
2/-
594
2/1/6
3/-
22/-
6/-
4/-
2/-
5/5/-
10/1/6
1/-
1/-
?
10/ -
7/-
1/6
2/-
3/-
3/-
1/-
3/-
2/-
4/4/-
5/-
?
4/-
2/6
31
KS
10/- +
4/6
5
4/-
3/6
0
6
5/-
5/-
1/-
594000
928
4/6
8
6/7/-
6
ST
WE
K3
4/6
1/6
3/-
2/-
LE
AS
E
1/6
3rd
From (F)
fts am
Dri in Se
Ma
2WE2 2WE1
6/-
4/-
7/6
2/3/-
3/-
1/6
5/-
3/1/6
4/-
5/-
4/6
O
F
2/6
7
0
ED
GE
3/-
2/-
928
7
2/-
1/-
2/6
3/6
12/ -
3/-
-/3
1/6
8/-
434
K.1
2/-
3/-
1/6
60
1/-
1/6
92
6/-
2/6
1/6
4/-
1/-
4/-
2/-
15/-
21/-
2/-
3/1/6
9880
2/6
K.3
40
93
4/3
2/-
15
9360
6/-
4/6
3/2/6
8
1/3/14/-
1 in
6/-
3/-
1/-
3/-
5/-
15
12/-
2/-
1/-
4/-
4/3
1 in
1/1/-
4/6
2/-
8/-
4/-
9890
2/5/-
2WE3
39/-
1/-
4/-
1/-
H
UT
SO
K3
11/-
50/ -
12/-
4/-
2/4/-
K.4
0
92
80
6/3
1/-
932
K.5
6/-
2/-
2/-
9/-
93
60
80
93
210/ -
4/-
K
1/6
0
93
20
20/-
3/-
2/1/6
35/2/-
4R
KO
7
934
100/- total
NI
WIN
8/-
4/-
K1
4/-
8/-
S
NG
20
K2
TH
OR
.N
3rd
K.8
K.6
1
KW
595000
19
K2
8
30/-
2
KW
5/-
10/-
10/-
15/-
20/-
K.21
0
K.2
596000
6/-
2
K.2
K7
4/-
13/-
Y
LE
8
4/-
6/-
C 42"
9
IL
SW
4
K.2
30/ -
20/8/ -
3/-
1/-
10/-
3/6
3/6(G)
6/-
4/-
1/5/-
6/-
2/9
4/-
2
K1
EA
AR
CE
EN
LIC
ING
AT
ER
P
O
1/6
UN
5/-
KNO
8/-
3-2
KW
593000
18
K.2
4/-
5/-
10
8/-
EDGEE OF
EDG
AREA
ASE
OF LE
9460
4/-
6
K1
9
K1
1/9
10
G LINE P.A.I.
37m WARNIN
REGS 1979
1
TH COLLIERY S
LYNEMOU
WORKING
BRASS THILL
NE
IT LI
SPL
597000
0
13/-
430
ED
GE
OF
LIC
EN
CE
AR
EA
OFFSHORE BOREHOLE No.17
BOREHOLE NZ 29 NE 52
C 21" K1
9581
EA
E AR
LEAS
948
RTH
NO
3rd.
Ellington Colliery Brass Thill Seam “ K” Plan
KDE1
300’
EL
AN
7P
K1
10
J 2K
J2.2.2 K 1
J2.2. K
J2.2. K
KS
Figure 4-7
4/-
8/-
A
K.73
K.72
2/6
5/4
5/-
1/-
SE
E
LIN
K.71
K.70
2/-
KW7
TO
K662
K661
K651
K641
KD3N
-1m
COVER LINE
00
96
600000
J 2.2.2 K 1
105m
J 2.1
150T STAPLE BUNKER
592000
J 2.2
No. 3 SHAFT
No. 4 SHAFT
J 2.1
J2
K1
No. 1 SHAFT
No. 2 SHAFT
No. 3 SHAFT
J2 K
J 2.2 K1
BEWICK DRIFT
K2
K2
ELLINGTON COMBINE
591000
UK COAL MINING LTD
PHASING
NOTE : For sake of clarity
Continuous Miner phasing
does not show years.
2002
2003
2004
LONGWALL EXTRACTION SHEARERS SHOWN
ELLINGTON COMBINE
G53R
PARTIAL EXTRACTION MINERS SHOWN
53
BRASS THILL "K"
DISTANCE FROM SHAFT (KILOMETRES) SHOWN
8
RESERVE AREAS
2005
2006
WORKINGS UPDATED
AUGUST 2002
SCALE
DATE OF PREPARATION
1/10000
AUGUST 2002
PAGE 63
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
PLAN DATUM
10,000ft BELOW ORDNANCE DATUM
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 64
Changes Between Reserve Assessments
Since 1998, the reserve at Ellington has increased by 0.434Mt from 2.834 to 3.268Mt. The
differences are discussed below and shown in Table 4-16
Reserve Zones
High Main (E) and Main (F)
The reserves in the Main Seam have increased by 0.197Mt from 0.421Mt to 0.618Mt. This is
due to an increase in the areas of Zones 5W and 5E, and also a new zone 5S.
Total
0.197Mt
Yard (G)
The reserves have reduced by 1.124Mt from 1.158Mt to 0.034Mt. (Now worked out). Zone
5SW has been abandoned and the remainder has been worked.
Zone 5SW abandoned
-0.197Mt
Zone 5 worked
-0.927Mt
Total
-1.124Mt
Brass Thill (K)
The Reserves have increased by 1.361Mt from 1.255Mt to 2.616Mt. This is mainly due to the
upgrading of resources to reserves in zones 1N and 2.
Zone 1N to reserve
+1.069Mt
Zone 2 to reserve
+1.430Mt
Zone 2WE3 additional
+0.117Mt
Zone 2E/W worked
-0.681Mt
Zone 6 part abandoned
-0.574Mt
Total
+1.361Mt
Resource Zones
The resources have decreased by 8.400 Mt to zero in 2002. The main change is due to the
abandonment of the area north of the Causey Park Dyke and the upgrading to reserves in the
Brass Thill Seam.
High Main Seam (E) and Main Seam (F)
All of the High Main E Resources were north of the Causey Park Dyke and have been
abandoned.
Zone 6 abandoned
-1.578Mt
There were no resources in the Main Seam F.
Yard (G)
Resources abandoned north of Causey Park Dyke
Zones 6W/E abandoned
-1.461Mt
Brass Thill (K)
Some areas of the resource in this seam have been abandoned and others upgraded to reserve.
Zone 1N upgraded
I5104C
-1.045Mt
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 65
Zone 6NE/NW abandoned
-2.128Mt
Zone 2W upgraded
-2.188Mt
Total
-8.400Mt
Mineral Potential
Mineral Potential has reduced by 1.735Mt from 2.009 to 0.274Mt. The Plessey Seam M has
been removed, but Zone 1S in the Brass Thill is still included.
4.4.3.4
Plessey Zones 5.1/6.1 abandoned
-1.741Mt
Brass Thill Zone 1S
+0.006Mt
Total
-1.735Mt
Exploration
Since the working areas are offshore, the only exploration is by development drivage and inseam seismic where applicable. No other exploration is planned.
4.4.3.5
Other Seams of Interest
There are no other seams of interest.
4.4.3.6
Geological and Reserve/Resource Conclusions for Ellington Colliery
The proposed longwall workings in the Brass Thill seam increase in risk to the south. The
311’ s current face is in a thicker section but on 310’ s the seam is only 1.33m thick. The 33’ s
to 38’ s panels require considerable access drivage in areas where the seam is only 1.4m-1.5m
thick, with strong sandstone close above. This may also give difficult cutting on the faces
especially in faulted areas. Panels 37’ s and 38’ s are shown as Mineral Potential as they
maybe affected by seam splitting and in small part lie outside the Lease area.
The remaining Main Seam workings are in a poorly proven area 13-14km from the shafts,
although this partial extraction area may be needed to improve the product from the Brass
Thill.
4.4.3.7
IMC Commentary on the Reserve/Resource for Ellington Colliery
The assessment has been completed in accordance with the assessment procedure and it is the
opinion of IMC that this is done correctly at Ellington with the degree of geological risk to
each of the areas being assessed accordingly. The only change in the reserve assessment that
should be made is the fact that at the present time the last remaining reserve in the Yard seam
has been extracted.
The removal of areas to the north of the Causey Park Dyke from the 2002 assessment, which
constituted the bulk of the tonnages shown in 1998, has been done for sound geological and
mining reasons. When these blocks were accessed in the Brass Thill (K) seam they proved
unworkable due to being affected by the igneous intrusion and were of very poor quality.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table 4-17
PAGE 66
IMC Re-assessment of Ellington Colliery Reserve/Resource (Dec 2002)
Million Tonnes
Seam
Reserve
Main F
0.618
0.618
Brass Thill K
2.616
2.616
0.274
Total
3.234
3.234
0.274
4.4.4
Resource
Total
Mineral Potential
MINE CHARACTERISTICS AND CONSTRAINTS
Production areas at Ellington are under the sea and layouts are constrained by mandatory
regulations. These are primarily concerned with depth below the seabed and the amounts of
extraction with residual coal pillars to limit seabed strain.
The older mine workings are extensive, in some areas reaching 16km from the shafts. The
previously accessible thick coal reserves in the north have been exhausted. In addition,
substantial coal reserves, north of the Causey Park Dyke, have been abandoned due to igneous
intrusions and the quality of the coal being adversely affected by heat.
At the time of privatisation, British Coal took the view that reserves at the mine were no
longer viable and therefore could be considered exhausted. Over the last few years, UK Coal
plc has worked the mine with only limited success recording financial losses in a number of
years.
Geographically, the mine is well placed to supply coal direct to the adjacent Alcan Power
Station. Because coal is transported by overland conveyor to the power station, transport
charges are minimal. The overall proceeds for this PSF type fuel are relatively generous.
Because Alcan is also burning imported coal, negotiating similar proceeds in the future may
prove difficult.
Output for 2002 is forecast to reach 753,000 tonnes against a budget of 725,000 tonnes.
Planned production for 2003 has been increased to 1Mt/a.
Future production plans are based on a discrete area of coal in the Brass Thill Seam adjacent
to Lynemouth Colliery. Output from this area will be supplemented by production from pillar
and stall units operating in the thicker ‘F’ Seam in the north-east. Output from these limited
reserves in ‘F’ Seam are planned at 250,000 tonnes/annum.
It is anticipated that sufficient coal is available to sustain the planned outputs over the next
four years with some 400 men although this may prove difficult to realise, with the
probability of significant losses through the period due to the exhaustion of the ‘F’ Seam.
4.4.4.1
Infrastructure
Ellington has an extensive infrastructure, which appears generally satisfactory throughout.
Since access is no longer required to the workings in the far north a more rationalised
approach can be taken to controlling operations in the Brass Thill Seam. Over many years
considerable investment has been made in installing and maintaining high-speed locomotives
for manriding and materials supply. Coal clearance and bunker capacity should adequately
support planned output.
Mine water pumping is at the rate of 3,500 gallons /minute.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.4.4.2
PAGE 67
Roadways and face conditions
Both main laterals and gate roads are supported with roof bolts. Conditions are generally good
throughout with little ‘spalling’ from the sides. Observations made underground would
indicate low vertical stress and low confinement stress in the roof strata. The Brass Thill roof
has variable characteristics and the seam is subject to localised thickening and seam splitting.
Overall, the new Joy 510, two-leg IFS Face Supports give improved roof control on the
faceline which have previously experienced problems. Unfortunately, the mine has only one
full set of these supports and therefore at the end of production from each longwall the mine is
faced with costly face gaps of up to 2 months. The plan for 2003 shows two such face gaps.
Support services for the Eickoff ‘In-Web’ 300LN Shearer currently deployed at the colliery,
will be difficult and therefore a Joy 4LS Shearer has been installed on the present 310’ s face.
Because of its physical dimensions, as the seam thins, floor dirt has to be taken to allow the
machine to traverse the face. At some stage in its future, Ellington will require a new type of
shearer and associated pan line. Additional investment will be necessary to cover this
requirement. These costs could be further increased if a second set of face supports is
required to eliminate the costly face gaps.
To access the last six faces planned in the Brass Thill Seam, two critical developments will be
required in cross-measure drifts through a known faulted area. Present rates of drivage into
this area are behind the planned schedule. If these rates do not improve they will result in a
face gap and a loss in production.
Observations made underground showed that good mining standards were being achieved.
Emphasis was placed on ensuring that men clearly understood the safety requirements within
their working areas. Considerable effort had been made on the outbye meeting stations to the
working districts. These were well constructed with comprehensive information available for
all workmen, including risk assessments, methods of work, codes of practice and other
relevant safety issues.
4.4.4.3
Ventilation
The present working area in the Brass Thill seam, which is some 6km from the shafts and
Bewick Drifts, can be ventilated. Any future reserves worked in the north within the Main
Seam and Yard Seam will present difficulties due to the excessive distances of 12km or more.
UK Coal plc has no plans to work these remote areas of coal except for the existing workings
in the ‘F’ Seam.
4.4.4.4
Coal Preparation Facilities
The plant was built in 1995, as a replacement for the oversized original plant, with a design
capacity of 450t/h including dry fines extraction. ROM from Ellington comes to the surface at
Lynemouth and into a ROM Bunker. The plant feed is taken from the bunker at a controlled
rate of up to 450t/h using an electromagnetic feeder. Excess ROM into the bunker is
automatically by-passed to Stock
The feed enters the plant feeding on to a Dry Fines Extraction Screen. The screen underflow
falls into a small holding bunker fitted with a variable speed extraction feeder. This product is
the dry constituent of the PSF Blend destined for Alcan. The oversize from the screen is
conveyed to a pre-wet screen preceding a three Product Dense Medium Drum. The separation
yields a clean coal fraction, the basis of the domestic product range produced by the mine;
middlings are crushed and added to the Power Station Fuel (PSF) Blend and a discard. The
underflows from the pre-wet screen together with the excess dry fines are fed to a de-sliming
screen. From the screen the oversize is treated by a pair of pump fed Dense Medium Cyclones
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 68
producing a cleaned coal product and a discard. The clean coal, having been dewatered in a
centrifuge, is added to the dry fines and the crushed middlings to form the blended PSF
product. The underflow from the de-sliming screen is pumped to a set of slurry cyclones, the
recovered solids are dewatered on a Multi Roll Filter (MRF) and can either be put into the
blend or out-loaded to ground stock. The Overflow from the cyclones is discharged into a
flume and into the sea. The Discard from the plant is dumped on the shoreline and pushed into
the sea.
Currently the mine is operating with a 50% vend. Some 5% of saleable output is graded
products (+25mm), the balance being PSF. The plant is operational 24hrs/day from midnight
Sunday to 6am Saturday processing between 25,000-30,000t/w. This gives a processing rate
ranging between 200t/h and 240t/h, against a design capacity of 450t/h. This is compared with
a mine output ranging between 35 and 40,000t/w when in production.
The current stock level of ROM is around 280,000 tonnes with space to store a maximum of
around 300,000 tonnes. There is around 30,000 tonnes of filtered slurry and around 10,000
tonnes of graded coals.
Process water for the plant is taken from the mine water reservoir. The plant effluent overflow
from the slurry cyclones is discharged into the sea via an open flume. Current legislation
dictates a limit of 20,000ppm suspended solids in the total effluent; hence the plant effluent is
diluted with excess mine water. There is a shortfall in fines treatment and effluent handling
for the plant to handle the future predicted tonnages and recover the ROM Stocks.
4.4.5
4.4.5.1
HISTORIC PERFORMANCE
Production
Table 4-18
4.4.5.2
Historical Production Performance at Ellington
Ellington
1999
2000
2001
Actual Output
million tonnes – saleable
0.762
0.217
0.629
Budgeted Output
million tonnes – saleable
0.856
0.090
0.600
Difference
million tonnes – saleable
-0.094
+0.127
+0.029
Development
Table 4-19
Historical Development Performance at Ellington
Ellington
1999
2000
2001
Actual Developments
metres
4,864
2,087
5,058
Budgeted Developments
metres
6,455
nil
5,201
Difference
Metres
-1,591
+2,087
-143
Ellington Colliery had been planned to close in 2000, however, production and development
re-commenced following the introduction of the Operating Aid Scheme.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.4.6
4.4.6.1
PAGE 69
PRODUCTION AND DEVELOPMENT FORECASTS
Production
Output for 2002 is expected to be around 780,000t, KS311’ s Face in the Brass Thill having
recently commenced production following an inter-face transfer of equipment from KS32’ s.
Two Continuous Miners have also recently started production in the final partial extraction
area within the Main Seam.
From 2003 onwards, production is planned to be at around 1.0Mt/a. 750,000t is to be
produced from a single retreat face in the Brass Thill Seam in an area to the South East
adjacent to old Lynemouth Colliery workings. This is supplemented by two Continuous
Miners planned to produce 250,000t working a partial extraction system within a small parcel
of Main Seam remaining to the north. It should be noted that only 600,000t of coal is
recoverable in this area. However, further coal supplements maybe derived from suitable
small remnant pillars to maintain planned outputs through to the exhaustion of the Brass Thill.
Longwall production within the Brass Thill seam utilises a single set of face equipment.
Inter-face transfers are planned to take 8 weeks; the use of Pony Loco’ s dictating the speed of
transfer. The panels are standardised at a face length of 245m. Working three shifts face
output is phased at 13 strips per day. KS311’ s has a variable seam thickness, ranging from
over 2.00m at its inbye end to around 1.40m at its finish position. The more southerly faces
adjacent to Lynemouth, planned to be worked from 2004 onwards, have a seam thickness of
just over 1.20m.
Future panel lengths are restricted to 1,000m at best and phased at nearly 50m/w retreat,
having a life of less than 5 months. This results in two face changes occurring every year. A
small panel, KS310’ s, which has a panel run of only 445m, is to be worked in the second half
of 2003. This face is required to give enough time for the substantial development of KS35’ s
to be completed.
The two Continuous Miners deployed to production from the Partial Extraction system are
both phased at 25m per day working three shifts. The seam is around 2.60m in thickness and
with a roadway width of 6m the units produce around 21t/m advance.
A total of six faces are planned in the southern area adjacent to Lynemouth. If all these faces
are worked then the mine will reach exhaustion by early 2007.
4.4.6.2
Developments
Four headings are required to support the face replacement programme. The heading teams
are also used to assist in completing the inter-face transfer of equipment. In-seam lateral
developments are normally phased at 45m/w and gate roads at 60m/w. All developments are
manned on three shifts. Around 5,800m of development drivage is required per annum to
maintain the longwall face programme.
The cross-measure drivages that are currently being undertaken to access the South West area
are phased at 30m/w. However, they are currently only averaging around 18m and are
slipping behind schedule, putting pressure on the ability to develop KS35’ s Face in time to
accept the equipment from KS310’ s.
4.4.6.3
Risk
Ellington is planned on a single face strategy with output from the single longwall face
supplemented by output from a limited area of Main Seam worked by continuous miner.
Because of support constraints due to the proximity of the sea bed, the Main Seam in this area
can only be worked on partial extraction.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 70
The principal geological risk to production in the Brass Thill Seam in the future is the
deterioration in seam section on KS310’ s (1.33m) and KS33’ s/KS34’ s (1.39m) when
compared to the current working face. The quality of the Brass Thill also raises concern if the
seam were ever to be mined by itself without the Main Seam output to blend with it.
Future faces in this seam have restricted face runs ranging from 1200m on the existing face to
450m on KS310’ s. the average for subsequent faces is 900m and at planned production rates
of 50m/week will have a life of less than 5 months. This will require two face changes a year
to maintain output. Currently the mine has, as part of its assets, a single set of face supports
which means that without an additional set of face equipment the mine will have no longwall
production for 16 weeks per year.
Four headings are required to maintain output in the seam and support the face replacement
programme. Currently gate roadways driven in seam are phased at 60m/week. Any slippage
in this programme will apply added pressure to an already difficult face replacement schedule.
Cross measure drivages currently underway to access the south west reserves phased at
30m/week are slipping behind schedule achieving only 18m/week putting the replacement of
KS310’ s with KS35’ s at risk.
To sustain the planned output of 1Mt/a from the mine would require an output of 250,000t/a
from the partial extraction in the Main Seam ‘F’ . IMC’ s and UK Coal’ s assessment of the
reserve in this area equate to some 0.6Mt indicating seam exhaustion within 2.5 years against
a plan of 4 years. On withdrawal from the existing area of Main Seam ‘F’ there may be
remnant areas of coal that could possibly be taken to supplement the production from the
longwall areas of Brass Thill, although these have not been identified.
The faces are planned to be worked at rates in excess of the present Coal Preparation Plant
(CPP) capacity. Noting that there is little stocking room left, it is probable that face
performance from spring 2003 onwards will be severely restricted by the capacity of the CPP.
4.4.6.4
Long Term Plans
The Brass Thill faces planned adjacent to Lynemouth represent the final reserves available at
Ellington. Assuming that all faces are worked as planned, the mine will reach exhaustion by
early 2007. There are therefore no plans to extend the life of the mine beyond this time.
4.4.7
OPPORTUNITIES FOR FURTHER INVESTMENT
With consistent loss-making and negative cash flows over the last four years, it is difficult
from a financial point of view to be convinced of future profits and cash inflow. However,
the mine has been regularly prepared for closure and this inevitably has an impact on its
performance. It has enjoyed premium prices for it’ s product but costs of production have also
been high. Predicted costs are at a value, which have not been achieved in recent years.
Future cash generation is predicted at £3m that restricts any potential project but also restricts
the increase in income needed to justify it. A £22M project would need five years of
consistent income to raise the cash and would then need six years of an income of £5m to
justify it. The present production plan for the mine has risk and is thought unlikely to
generate these levels of cash.
With limited reserves and a poor financial history it would be difficult to substantiate capital
investment at this mine. The colliery has been at risk of closure for many years and although
it has a production plan to early 2007 it remains in monthly review. In the immediate term
the mine has a serious capacity problem within its coal preparation facility. With limited
stocking room remaining for the run of mine product, face production could soon be inhibited.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 71
If mining is to continue then a solution needs to be urgently found to this problem with
investment in the requisite coal preparation equipment.
Other potential investment expenditure is restricted to a new shearer and AFC that could be
sourced from elsewhere within the company. These items of equipment would need to be
compatible with the thin seam requirements at Ellington. Currently the mine only has a single
set of face equipment. If developments could be advanced then there could be potential for
the procurement of a second set of face equipment to avoid production gaps. This could
protect output levels as the more northern pillar and stall workings become depleted. These
should be Category 1 projects but the probable lower return may mean that without grant aid,
they might not proceed and therefore they fall into Category 2 albeit that as previously stated
the limited reserves and a poor financial history would make project viability doubtful.
Overall the present production plan would indicate and insufficient payback period and a real
risk for further losses.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.5
HARWORTH COLLIERY
4.5.1
BRIEF DESCRIPTION OF SITE
PAGE 72
Harworth Colliery is located in Nottinghamshire, 12km south of Doncaster on the southern
periphery of Harworth village. The mine site has good access to the nearby A1 (M) trunk
road and is adjacent to the UK Coal plc Headquarters and Harworth Plant.
The colliery was established between 1919 and 1924, since when, five seams have been
worked, Top Hard, Blyth, Deep Soft, Haigh Moor and Swallow Wood. Current production is
from the Deep Soft Seam, which commenced in 1981. RJB Mining (latterly to become UK
Coal plc) took over the mine in January 1995, at which time it was in full production.
Harworth has two 6.8m diameter shafts, No 1 and No 2, which were originally sunk to a depth
of 908m and 896m deep respectively. However, No 2 shaft has been deepened to the Deep
Soft Seam at a depth of 1,005m. Extensive work to replace both sets of headgear was
undertaken in the 1990’ s, having been started under British Coal and completed by RJB
Mining.
The main colliery site has an area of around 36 hectares. The mine has a comprehensive
range of surface buildings including a coal preparation plant and rail outloading facilities, the
site being connected to the rail network. In addition there are coal-stocking areas amounting
to some 11 hectares and a further 126 hectares of land consisting mainly of spoil tips.
The mine has four access roadways into the Deep Soft Seam from the pit bottom area which
is in the Top Hard Seam. The current working area is south east of the shafts.
4.5.2
MINE BOUNDARIES, OTHER SURFACE CONSTRAINTS AND ISSUES
Except for the northern boundary with Rossington Colliery, all other licence boundaries are
defined by geological features. Production has been concentrated at a depth of about 1000m
in the Deep Soft Seam, which has an average thickness of 2.9m in the south and 2.1m in the
north. Sulphur content averages 3.0% and chlorine 0.3%. The mine also has an area of Top
Hard that is shallower and to the east of the present Deep Soft workings in the north. The Top
Hard has a thickness of 1.70m to 2.40m, sulphur 1.4% and Chlorine 0.5%.
4.5.3
GEOLOGICAL ASSESSMENT OF THE MINE
Harworth Colliery is situated in the Eastern Pennine Basin Coalfield. The northern boundary
is with the active Rossington mine, while the other limits are geological, either seam splitting
or washouts. The Coal Measures lie unconformably below gently dipping Permo-Triassic
formations.
4.5.3.1
Structure
The main structural feature is the northwest-southeast trending Ranskill Anticline with the
seams dipping away from this at 1 in 15 to 1 in 20. In the northern area of the reserves is the
large east-west Lings Fault, which has been identified from surface seismic surveys. At the
southern edge of the Deep Soft workings is a northwest-southeast fault (also from seismic
surveys) with an expected throw of 25-30m.
4.5.3.2
Seams in Reserves
The following seams are considered to be in the reserve classification for this mine. These
are: -
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
•
Top Hard (Barnsley) Seam
•
Deep Soft Seam
PAGE 73
These seams are located within the Lower and Middle Coal Measures and are overlain by
Permo-Triassic strata containing aquifers, but these are not close enough to be a risk.
Seam Characteristics
The Top Hard Seam
The roof measures of the seam are weak mudstones overlain by slightly stronger silty
mudstones and siltstones. No sandstones are expected on or close to the seam.
The Top Hard Seam in the main part of the mine has long been worked out. However, an
area of combined Top Hard, Blidworth and Dunsil seams is present 6-14km east of the shafts.
The data is limited, but the seam is expected to be 1.70m-2.50m thick including 0.15m-0.60m
of dirt and is bounded to the north and south by the splitting of the seam between the Top
Hard and Blidworth sections.
In general the quality of the seam is expected to be: As mined ash
15-40%
Clean coal ash
7-13%
Sulphur
1.2-1.8%
Chlorine
0.4-0.5%
The floor of the seam is expected to be weak mudstone seatearth of variable thickness, that is
prone to floor lift as the seam is worked.
The Deep Soft Seam
The major feature present in the roof of the Deep Soft is a sandstone roof belt with washouts
trending southwest-northeast, that forms the easterly-southeasterly limit of the reserves in this
seam. Minor channels and areas of sandstone are known on the edge of this belt, and could
affect part of reserve zone Ds. In the northern part of the reserve area the roof is expected to
be mudstone and silty mudstone passing upwards to sandy siltstones.
The Deep Soft is a combination of the Roof Soft, Top Soft and Deep Soft seams and the
thickness varies from 2.86m (including 0.52m dirt) in the south, to 2.10m (including 0.24m
dirt) in the north. An additional area (Zone En) is shown in the far north at 1.20m thickness
where the seam has split. Swilleys occur in the floor of this seam, and these are often
associated with seam thickness and gradient variations.
Again the expected quality of the seam is shown below: As mined ash
6-24%
Clean coal ash
7-16%
Sulphur
2.7-3.4%
Chlorine
0.2-0.4%
The seam has a variable floor, and swilleys are fairly common as mentioned above. These
may be associated with zones of hard floor, minor faulting and gradient changes.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.5.3.3
PAGE 74
Reserves/Resources Assessment
Two seams are shown in the assessment dated July 2002. The Top Hard seam is shown as
Indicated Resources as the provings are limited, and there is no current access. The Deep Soft
seam is shown as Proven and Probable Reserves, and there are also Indicated Resources to the
north and south of the main area.
Position with regard to Reserves in 1998
The reserves/resource available at Harworth in 1998 were as summarised in Table 4-20 below
based on the knowledge at that time. These have changed up to the last assessment in 2002 in
the light of more detailed information and a comparison will be made of the changes later in
the report.
Table 4-20
Harworth Colliery Reserve/Resource Summary (01/07/98) (Source: RJB
Mining)
Million Tonnes
Seam
Reserve
Resource
Total
9.207
9.207
Top Hard
Deep Soft
22.178
12.763
34.941
Total
22.178
21.970
44.148
Mineral Potential
Position with regard to Reserves/Resources in 2002
The Deep Soft is the only seam worked since 1998. Zone B has been downgraded from
Reserve to Resource. The Top Hard Resource has been increased as a result of drilling Carr
Road borehole since the last review in 1998. A summary is shown below in Table 4-21.
Table 4-21
Harworth Colliery Reserve/Resource Summary (01/07/02) (Source: RJB
Mining)
Million Tonnes
Seam
Reserve
Resource
Total
13.970
13.970
Top Hard
Deep Soft
6.027
20.067
26.094
Total
6.027
34.037
40.064
Mineral Potential
Changes Between Reserve Assessments
Deep Soft
The changes in the assessments are detailed in Table 4-22. During the period 1998 to 2002,
the Proved and Probable Reserves have decreased by 16.151Mt from 22.178 to 6.027Mt. The
seam has been worked throughout the period, and some of the Reserves have also been
downgraded to resources.
The major change is that 8.493Mt of probable reserves in Zone B have been downgraded to
resources as there are no plans to access this through a 25m-30m fault.
Zones where coal has been worked or abandoned due to mining difficulties:
I5104C
Zone C1n (8’ s panel)
-1.459Mt
Zone C1 (10’ s and 20’ s panels)
-3.387Mt
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 75
Zone Ds
-1.299Mt
Zone Dn part (17’ s panel) estimate
-1.200Mt
Sub Total
-7.345Mt
Zone B downgrade
-8.493Mt
Adjustments for layout changes
-0.313Mt
Total Change
-16.151Mt
Resource Zones
The Deep Soft Seam
The Deep Soft Resources have increased by 7.304Mt from 12.763Mt to 20.067Mt.
Zone A
reduced area
-1.298Mt
Zone B
from Reserves
+7.144Mt
Zone Cii
New area
+0.873Mt
Zone De
reduced area
-1.359Mt
Zone Es
changed zone
+0.364Mt
Zone Dnii
new zone
+0.498Mt
Zone Dwn
from Reserves
+0.667Mt
Zone Dwsi
from Reserves
+0.415Mt
Total change
+7.304Mt
The Top Hard Seam
There have been no workings in the period 1998 to 2002 in the Top Hard, and the resource
quantities have increased by 4.763Mt from 9.207Mt in 1998, to 13.970 Mt in 2002. This is
due to the drilling of two surface boreholes since the 1998 assessment, and the more northerly
one (Carr Road) proved that the limiting split line was further north than the previous
interpretation and that the seam was slightly thicker. This has allowed an increase in all zones
except Fs and Ds, which are in the south of the area.
Total Change
4.5.3.4
+4.763Mt
Exploration
The Top Hard resources need additional structural and seam provings, and UK Coal plc
indicate that 30-35km of surface seismic and a further surface borehole would be required
prior to any commitment to access this area.
The Deep Soft area of Zone Ds has limited structural proving, and the southern end is close to
the major washout. The 30’ s, 32’ s and 34’ s panels are at risk, and although the development
roads will establish the position of the sandstone, any faulting can only be investigated by
surface seismic surveys. These problems are appreciated by UK Coal plc and are referred to
in their Five Year Plan reports.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 76
Table 4-22
Dn
Dc
Ds
Fn
Fc
Fs
A
B
1998
RESERVE (Mt)
RESOURCE (Mt) Mineral Risk Factor Block
or
Proven Probable Measured Indicated Potential Tect Sed
Zone
(Mt)
Panel
1.012
4
4
B
Dn
2.086
4
3
B
Dc
0.328
4
4
B
Ds
0.921
5
5
B
Fn
4.260
5
4
B
Fc
0.600
5
5
B
Fs
4.690
3
4
B
A
8.493
3
3
B
p
C1n
C1
C2
1.459
4.335
0.465
1
2
1
2
2
2
P
P
C1
Ds
Dn
De
Dwn
1.299
2
3
2
3
2
2
5
3
P
P
B
B
Cii
Ds
Dn
De
Dwn
SEAM
Zone
Top Hard
Deep Soft
3.711
2.084
2.416
Harworth Colliery Reserves and Resources Comparison
2002
RESERVE (Mt)
RESOURCE (Mt) Mineral Risk Factor Block Change
Reason for Change
Proven Probable Measured Indicated Potential Tect Sed or Panel
(Mt)
1.243
4
3
B
+0.231
Increased by results of Carr Rd borehole
2.228
4
3
B
+0.142
Increased by results of Carr Rd borehole
0.328
4
4
B
No change
1.729
5
3
B
+0.808
Increased by results of Carr Rd borehole
7.842
5
3
B
+3.582
Increased by results of Carr Rd borehole
0.600
5
5
B
No change
3.392
3
4
B
-1.298
Reduced area
7.144
3
3
p
-1.349 and downgraded to Doubt of access, increased deductions
Resource
-1.459
Worked
0.948
2
2
p
-3.387
Worked and partially abandoned
-0.465
Abandoned
0.873
3
5
+0.873
New area but surface constraints
1.967
4
4
P
+0.668
Part worked. New zone larger includes 30,32,34s panels
1.116
2
2
P
-2.595
Worked and part transferred to Dnii
0.725
4
5
B
-1.359
Area reduced
0.667
2
3
P
-1.749
Part to zone Dws rest downgraded
Es
2.780
3
4
B
Es
0.569
5
4
P
-2.211
Most of zone now in Esi
En
3.209
3
5
B
En
Dni
3.209
1.263
3
2
5
3
B
P
No change
+1.263
Was part of old zone Dn
Dnii
Dws
0.498
0.733
4
3
3
3
P
P
+0.498
+0.733
Was part of old zone Dn
Was part of old zone Dwn
0.415
2.575
3
3
3
4
P
B
+0.415
+2.575
Was part of old zone Dwn
Was part of old zone Es
Dwsi
Esi
TOTAL
I5104C
7.558
14.620
21.970
2.064
3.963
34.037
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
I5104C
396000
395000
En
394000
U
393000
U
U
U
U
Esi
392000
U
9 DS
U
0c
n 5
w of
Bro
e of
Centr
390000
y
Swille
DS
5
illey
Sw
w
Bro
of
Sw
illey
Boo ster
Fan
DS
3
ts
to
ne
/
st
on
e
n
50
cm
hi
50
wit
Sa
e/
on
st
lt
DS
Centre of Swilley
389000
e
e
l
Si
nd
Sa
Boo ster
Fan
wi
th
in
illey
on
of
Sw
y
ille
Sw
nd
Brow
of
st
re
nt
Ce
Si
1
r red
Infe
Ed
ge
of
d Dis
a lise
Loc
bed
tur
f Zon
Aircrossing
R oo
Proposed
Aircrossin g
De
Dn
1010
2.3 DS
5.2
5 .2 DS
DS
3
n 5
0c
m
DS
DS
0.5
10 DS
0.6
6
Si l t st
o ne/ Sa
n ds
t o ne
wi t h
i
Ds
DS
4
Boo st er
Fan
DS
Brow
of
Sw
illey
of
Sw
ille
Of
Sw
illey
t st
Si l
on e/
d
San
st o
ne
50c
hi n
wi t
m
y
wi t
hi n
50 cm
1
Br
ow
11
Ce
nt
re
DS
Ds
An
tic
lin
e
2
Ds
Ra
ns
kil
l
1.6
one
388000
dst
DS
2
/ Sa
n
Si l
t st
one
O ry
GD nda
m
ea Bou
ft S ce
So en
ep Lic
De ase\
e
dL
an
386000
st
nd
Sa
Aircrossin g
Sma
ll Fa
Pro posed
Aircrossing
ult
DS
985
e
on
on
p
To
ft
So
20
W
Ci
a
t
ou
sh
of
m
Co
bi
d
ne
a
Se
m
REFERENCE
SEAM CODE LETTER
DS
Boreholes
Cii
L 20
02
387000
DS
10
JU
Harworth Colliery: Deep Soft Seam Plan
DS
14
cm
0.5
Pro posed
Aircrossin g
i
Dn
Boo ster
Fan
i
Dn
m
Barnsley
Seam
Workings
Waterlogged
Barnsley
Seam
Workings
Waterlogged
Dn
ii
2003
hi
wi t
ne
st o
No.2
Spoil Heap
Dw
s
Dw
n
Es
AP
R
nd
/ Sa
one
Barnsley
Seam
Workings
Waterlogged
Pillar
lf Depth
Line Ha
ast Main
East Co
t st
Dw
si
Barnsley
Seam
Workings
Waterlogged
illar
f Depth P
Line Hal
st Main
East Coa
391000
No.3
Spoil Heap
Si l
Figure 4-8
No.1
Spoil Heap
B
Faults:
Proven
2.3
Projected
5
Proven in Top Hard Seam
TH 2.3 2.3
Fault throws shown in Metres
Top Hard Seam Workings
O y
GD ndar
m
a
ou
e
ft S nce B
o
S ice
ep
De ase\L
e
dL
an
B
385000
B
B
384000
Deep Soft Seam Workings
Sedimentology of Deep Soft Roof
Swillies within Deep Soft Seam
East Coast Main Line Half Depth Pillar
Deep Soft Reserves Areas
2002
2003
2004
2005
2006
B
383000
A
382000
UK COAL MINING LIMITED
HARWORTH COLLIERY
DEEP SOFT SEAM
RECOVERABLE RESERVES
381000
REFERENCE
DATE JULY 2002
SCALE : 1/10,000
468000
467000
466000
465000
464000
463000
462000
461000
460000
500
1000m
PAGE 77
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
459000
0
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
MISTERTON
NEWINGTON
393
IDLE
Harworth
Top Hard
Workings
PASTURE FARM
392
Barrow
Hill
Sandpit
SSSI
Es
TETHERING LANE
WOODEN BECK
2000
Mid Hards Split 50cms
Blidworth
Split 50
WISETON
Ds
Seam
s
200cm
MATTERSEY QUARRY
rds Split 0.50m
Mid Ha
Fs
cms
HIGHFIELD FARM
REFERENCE
DS
SEAM CODE LETTER
Ds
Boreholes
Faults
Top Hard Seam Workings
SSSI
ms
Seam 150c
1.0m
plit
S
s
d
BEECH VILLA
Har
Mid
.5m
it 1
l
Sp
ds
r
a
dH
Mi
BLACO
Deep Soft Seam Workings
East Coast Main Line Half Depth Pillar
Seam 100cms
e
ain Lin
oast M
r
East C Depth Pilla
Half
MALTHOUSE
387
Fc
Seam
200cm
s
MATTERSEY
Ds
MATTERSEY HILL
388
Dc
WARREN
Ds
Harworth
Deep Soft
Workings
i
Dn
i
Dn
Dn
20
0c
m
s
Dn
BECKINGHAM NO 35
GRINGLEY ON THE HILL NO 1
Se
am
Surface
Seism
ic Pro
ving of
Lings
LINGS WOOD
Wood
Fault A
ug
Dn
ii
389
SMITHS BRIDGE
CARR ROAD
SCAFTWORTH
390
Blidworth Split 50 cms
Fn
SCAFTWORTH NO 2
OIL BORE
391
477
476
475
474
473
472
471
470
469
468
466
467
PAGE 78
Top Hard Reserves Areas
NORTH WHEATLEY
UK COAL MINING LIMITED
HARWORTH COLLIERY
TOP HARD SEAM
386
LOUND
CLAYWORTH
DANES
RESERVE AREAS
REFERENCE
DATE JULY 2002
SCALE : 1/10,000
0
500
1000m
385
Figure 4-9
I5104C
Harworth Colliery: Top Hard Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.5.3.5
PAGE 79
Other Seams of Interest
There are no other seams of interest.
4.5.3.6
Geological and Reserve/Resource Conclusions for Harworth Colliery
The Deep Soft reserves are now concentrated in the northeast area and could be exhausted in
the Five Year period. Reserves in the south have been abandoned for the time being due to
access and quality, and other areas are affected by surface constraints. Approximately half of
the faces in the Five Year period (30, 32 and 34) are at risk from unknown faulting and
variations in the position of the major seam washout, and require further exploration which is
being undertaken.
The Top Hard requires considerable expenditure on exploration before access can be
considered.
Depending on the rate of proving in 30’ s roads, the Five Year Plan is at high risk after 19’ s
face has been worked.
4.5.3.7
IMC Commentary on the Reserve/Resources for Harworth Colliery
The only seam left accessed and working at Harworth at the present time is the Deep Soft
Seam and apart from the Top Hard is the only seam shown in the assessments for reserves and
resources.
Upon examination of the assessments IMC have concluded that these have been completed in
accordance with the definitions of the assessment procedure.
It is noted however that UK Coal plc has no intention within the current five year plan of
accessing the south area of the mine, Zones A and B, through a major fault. These resource
zones have limited proving, very limited in the case of Zone A, and have in general a thicker
but much dirtier section than the present working area. As the mine is pulling out of the
adjacent area (Zone Ci) after the working of that zone, then there is a case for downgrading
these resources to mineral potential on the grounds of lack of access. This is certainly the
case for Zone A although Zone B is in the strictest terms of the assessment given as the
correct category. On the assumption that the current access is lost then these zones should
become mineral potential or removed from the assessment
A similar case to the above can also be made for Zone Cii which cannot be readily accessed.
This zone is also subject to subsidence restrictions beneath the East Coast Main Line and is
almost entirely within the support pillar for that line.
This subsidence restriction also applies to Zones DWs and DWn in the present working area
of the mine where at least one face was originally planned to work within the Five Year plan.
The working of these panels has been deferred although they can be readily accessed from the
existing infrastructure. UK Coal has stated their intention to investigate the future working of
this area by a more acceptable layout. IMC is of the opinion that options for acceptable
layouts appear extremely limited.
Three other zones at Harworth, Zones Es, Esi, and En, situated to the north of the present
workings are also in the position where there is no intention to work them.
•
Zone En is remote and only has a Deep Soft section of 1.20m (possibly the upper leaf
only).
•
Zone Es is in an area of very steep dips, north of a major 40m throw, east west trending
fault. The length of rock drivage necessary to access and the steep dips would present
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 80
some mining difficulties and would probably preclude working this panel. Again for this
zone there is limited structural proving and the area could be at risk from runners off the
major fault to the south of the zone.
•
Zone Esi is to the north east of zone Es. This area is remote with no present access and is
poorly proved. Dips are expected to be more favourable in this zone but there is limited
structural proving and faulting could be present. This zone must also be subject to
thickening dirt parting within the seam as the split line is approached.
Taking into account the above comments, IMC believe that for all these zones again there is
the case to lower the category to Mineral Potential based on access and provings.
Of the remaining zones, the three faces in the Five Year plan in Zone Ds are at present at risk
from unknown faulting and limit of the washout belt to the east. IMC believe that these zones
should be lowered in category to resources until the results of further exploration planned by
the operator become available. If these results are favourable then these could be regenerated
back to reserves.
IMC believe the risk to the rest of the zones as given in the reserve plan are correct and that
there should be no changes in the categorisation of these zones. These zones are Dn, Dni,
Dnii and De.
The only other seam available to Harworth is the Top Hard seam. This seam lies some 100m
above the Deep Soft and at present has no access. The first available zones are located some
6kms east of the Harworth shafts and almost directly over the planned working area in the
Deep Soft. The area of coal available to Harworth then is a 2 to 2.5km wide zone lying
between 6 to 14kms east of the shafts. Accessing this area would be difficult and costly.
The zones in the Top Hard are all at present categorised as indicated resource and again there
is the case for downgrading this to mineral potential. A similar area analogous to this is seen
at Daw Mill where the southern reserves, even though they are in the same seam as is being
worked at that colliery, are assessed as mineral potential due to distance from the shafts which
are similar to Harworth. However Harworth also has the added disadvantage of the seam
lying some 100m above its present working horizon.
Taking all the above comments into account IMC have re-assessed the reserves and resources
at Harworth in the following table.
Table 4-23
IMC Re-assessment of Harworth Colliery Reserve/Resource (Dec 2002)
Million Tonnes
Seam
Deep Soft
Reserve
Resource
Total
Mineral Potential
3.327
3.190
6.517
19.577
Top Hard
Total
4.5.4
13.970
3.327
3.190
6.517
33.547
MINE CHARACTERISTICS AND CONSTRAINTS
Historically Harworth has operated with a two-face economy. Recently UK Coal plc have, in
an effort to reduce costs, adopted a single face strategy. The company has announced that the
present face DS22’ s will be the last face in the southern area of the mine worked from the
current infrastructure. Future production will be rationalised with operations confined to the
northern section of the mine. Additionally two previously planned longwalls that were to be
sited adjacent to the northern section have been deferred. This decision was taken on the
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 81
grounds of unacceptably high estimated subsidence damage costs (East Coast Main Railway
Line) and negotiations are to be undertaken with Network Rail in an effort to resolve the
issue.
DS22’ s face is planned to finish production in April 2003. Its replacement face DS19’ s in the
north is being developed. These developments are progressing to a point at which the inbye
faceline is being driven. To complete the installation of equipment; face supports will be
required from the adjacent DS17’ s. In order to facilitate the removal of these supports an
enlarged section is being made along DS17’ s faceline. This slow and arduous task is planned
to finish in early February 2003.
Activities on DS17’ s are further increased by the need to extend each of the gate roads to a
position inbye of the present faceline. At this point access will be made to develop the first of
the five, planned inbye faces. Additionally to those activities, extensive areas of floor will
require dinting in DS17’ s main gate. Clearly over the next six months, there are many tasks to
complete if the overall plan is to be achieved.
In the longer term, the five inbye-planned faces are at some geological risk, through
deterioration of the seam. Exploration is planned in this area in the early part of 2003, to
obtain a better understanding of the geology and reduce the risks of abortive development.
Conditions in the Deep Soft at Harworth are characterised by high ambient temperatures and
relatively high gas emissions as the seam is being worked. This necessitates considerable
effort being directed to maintaining adequate airflows through working districts and
maximising methane drainage capture efficiency in working faces. Over the years, much
experience has been gained at the mine in controlling the ventilation requirements and
associated problems. In adopting a single face strategy with annual outputs planned at 1.5M
tonnes, these constraints will require continual addressing.
All gate roads are now supported by roof bolts. Observations in DS19’ s return gate road
indicated satisfactory control of the roof is achieved using a dense pattern of bolts. Further to
the initial roof bolting, the first 4m of roof height is then pre-stressed by installing a pattern of
high tension, point anchored cable bolts. The latter is then rendered with full column
injection at a suitable distance outbye of the roadheading machine. Whilst conditions in the
roadway are satisfactory a further assessment maybe required when the face starts production.
In the zone of the front abutment, increased stress may result in excessive floor lift and ribside
movement. If this can be controlled to maintain a reasonable cross-sectional area then the
requirement to maximise airflows through the district can be continued for the life of the face.
If this is not the case then the result will be a fall in the face output (production constrained by
gas).
At present the mine is operating with some 490 men and this year will achieve over 5,000m of
development drivage. Production costs for the year are high. Nevertheless over the last two
months average weekly outputs have exceeded 25,000 tonnes from DS22’ s. In the month of
October average production costs were substantially reduced. This for the mine represents a
real turnaround situation and by the end of the year, it is hoped that a significant reduction can
be made to the cumulative losses.
Longer-term prospects for Harworth are limited. The identified area of Top Hard has little
cover from seismic surveys and boreholes. This is particularly relevant regarding seam
splitting and the effects of washouts. Access into this area would be long and could involve
cross-measure drivages in excess of 2,000m. Substantial transport systems would be required
for men and materials. Total costs of such a project would be high set against a relatively
small amount of recoverable coal. Nevertheless, UK Coal plc plans to carry out surface
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 82
seismic exploration in 2003. If the results prove favourable in the Top Hard then UK Coal plc
may decide to move to a detailed feasibility study to fully appraise the costs.
4.5.4.1
Ventilation
With the finishing of production within the South and the sealing of the main road circuit,
sufficient air will be available within the North and North East with the combination of Main
and Booster fans. The use of three road system of ventilation will not be practised in the
North East which will put significantly more reliance on the methane drainage systems and
effective management. Effective methane drainage has been demonstrated but there is a
requirement to ensure that the pipe range diameters are as large as possible in both the main
roadways and the face gate roads.
IMC also consider that there is a need to plan outputs that are realistic in terms of methane
constraints. An output approaching 1.5Mt/a using a single face economy may prove difficult
to achieve.
DS17’ s gate roadways are suspect longer term, as the main access roadways to five other
panels, due to the spontaneous combustion risk.
4.5.4.2
Subsidence
Deep Soft Seam
Reserve Zones A, B and Cii:
plans.
Reserve Zones A, B and Cii are not included in recent
Reserve Zone Ci:
Panel DS22’ s is currently working in this area with Torworth Village
being affected to a small extent. Subsidence damage costs are estimated to be less than 10
pence/t.
Reserve Zone Ds:
Mattersey Village lies in this area and the River Idle will be affected.
These panels are in the five-year development plan. The panel nearest the village and river
has been estimated to cost around 60 pence/t with the remaining panels at 20 pence/t.
Average costs for the whole area are estimated to be 30 pence/t.
Reserve Zone Dn and Dni: 19’ s, 31’ s and 33’ s Panels in this area are planned to work
during the next five years. Mattersey Thorpe Village will be affected but of greatest
significance is the River Idle. Subsidence damage costs are estimated to be 75 pence/t.
Reserve Zone Dnii and Es: 21’ s and 23’ s Panels are planned to work in this area but they
are not shown on the five-year development plan. The land in this area is agricultural and
woodland. There is also a small SSSI area.
Subsidence damage costs have been estimated to be low at around 20 pence/t.
Reserve Zone Dws, Dwsi and Dwn: Scrooby Village will be affected as will the River Idle
and the East Coast Main Line. There is also a main drain in the area.
Subsidence damage costs for this area will be high at an estimated cost of £10/t; such costs
could preclude viable mining.
Top Hard Seam
Subsidence damage costs will be generated by undermining Mattersey, Gringley on the Hill
and Everton villages. Costs will also be incurred for mining under the River Idle and the
Chesterfield Canal.
The land in the north east of the area, however, is low lying at only 3m above sea level and a
major pumping scheme may be required.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 83
The south part of the area may generate subsidence damage costs of some 50 pence/t but costs
in those areas where damage is already a problem may preclude mining.
4.5.4.3
Coal Preparation Facilities
Harworth Colliery has facilities rated at 500t/h, equating to around 50,000t/w or 2.4Mt/a. The
operations include dry fines extraction, large and small coal dense medium systems, froth
flotation and water clarification. The main product is PSF, a blend of dry fines and cleaned
small coal. Larger fractions are for the domestic market.
4.5.5
4.5.5.1
HISTORIC PERFORMANCE
Production
Table 4-24
Historical Production Performance at Harworth
Harworth
1999
2000
2001
Actual Output
million tonnes – saleable
1.586
0.928
1.077
Budgeted Output
million tonnes - saleable
1.700
1.650
1.500
Difference
million tonnes - saleable
-0.114
-0.722
-0.423
Production in 2000 and 2001 was very badly affected by geological faulting that developed on
DS20’ s advance face near to its tailgate end. This necessitated shortening off the face, which
proved difficult and time consuming to complete.
4.5.5.2
Development
Table 4-25
Historical Development Performance at Harworth
Harworth
1999
2000
2001
Actual Developments
metres
3,919
3,496
5,579
Budgeted Developments
metres
4,715
7,810
7,058
Difference
Metres
-796
-4,314
-1,479
Development in 2000 was badly affected by geological difficulties that were encountered in
D10’ s gate drivages and the main south laterals. The difficulties in DS10’ s eventually
resulted in the main gate drivage being stopped prematurely. In 2001 a change in strategy
was undertaken, the mine adopting a single face retreat economy in favour of retaining two
faces.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.5.6
PAGE 84
PRODUCTION AND DEVELOPMENT FORECASTS
Until recently Harworth Colliery has pursued a two-face retreat strategy extending the mine’ s
infrastructure to both the north and south, working a single face in each area simultaneously.
In recent years the mine has suffered substantial set-backs in its effort to establish full retreat
mining. In 1998 DS8’ s retreat face was lost due to spontaneous combustion and in 2000 the
development of DS10’ s 300m retreat face had to be aborted due to seam deterioration and
adverse geological conditions associated with faulting. This resulted in the mine reverting to
expensive advance faces. In 2000 the mine consequently applied for and received operating
aid.
In the years 2000 and 2001 production from D20’ s advance panel in the south area was very
badly affected by a large fault running on the face close to and parallel with the tail gate end.
At this time, ventilation calculations for future faces cast doubt on the ability to adequately
ventilate two faces simultaneously to avoid operational problems with methane emissions.
The decision was therefore taken in 2001 to adopt a single face retreat strategy with the
commissioning of D22’ s retreat face in 2002 being the last in the south.
Problems continued to accumulate in the early part of 2002. Production from D17’ s advance
face was badly affected by some uncertain geology that affected roof control and deterioration
in the condition of the armoured face conveyor (AFC). This eventually resulted in the face
ceasing production prematurely as parts of the AFC collapsed and became inoperable. This
induced a protracted gap in production whilst the development and installation of D22’ s face
was completed. This confined production for the first half of the year to just over 400,000t.
In addition subsidence problems became evident regarding the working of D7’ s face in the
North Area to the west of the North Laterals. This face was to have provided the replacement
for DS19’ s in early 2004. The face is planned under the East Coast Main Line and in
negotiation with Network Rail regarding preventative works to protect the railway it became
evident that estimated subsidence costs would be prohibitive (£10/t or £0.41/GJ). This has
resulted in the face being excluded from the current mining plans. There could also have been
opportunity for a second panel to the north and adjacent to D7’ s but this has also had to be
deferred for the present.
In the south area, the main lateral drivages had come to a halt in a zone of highly disturbed
ground with steeply dipping gradients associated with a major geological fault. This greatly
hindered progress and the impetus to developing south to secure replacement faces beyond the
fault was lost.
With this background UK Coal plc made it clear that the future of the mine was in jeopardy
and that its performance would be reviewed monthly whilst a way forward to secure
replacement face room on an economic basis was sought. In the event performances in
DS22’ s during the latter part of 2002 have been encouraging and the mine has come forward
with a proposal to work a sequence of faces inbye of D17’ s advance face (30’ s Area). On this
basis UK Coal plc announced on 12th December 2002 that “ mining operations at Harworth
are to continue following the production of a viable business plan. Progress will be
monitored closely over the coming months. The ongoing success of the plan is dependent
upon the geology in a new area of the mine being confirmed by seismic survey results due in
April 2000” . The following refers to the plan that has currently been adopted.
4.5.6.1
Production
The draft Five-Year schedule is as follows:
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table 4-26
Face
Tonnes
in Panel
PAGE 85
Draft Five-Year Schedule
2002
2003
2004
2005
2006
Development (metres)
5,758
5,388
5,700
6,219
5,000
Total Output (Mt)
1.157
1.437
1.317
1.274
1.306
South Area
DS22
433,000
North Area
DS17
DS19
1,208,000
30’s Area
DS30
1,077,000
DS32
986,000
DS31
806,000
DS34
926,000
The plan hinges on being able to access a series of faces at the inbye end of DS17’ s Advance
panel by repairing and re-using its gate roads as access tunnels.
DS22’ s, which has averaged 27,976t/w since a booster fan upgrade, is phased to continue in
production until May 2003. To maximise the life of the panel it is not intended to leave a
pillar of protection against the main south lateral tunnels. The face will therefore be retreated
as far as is physically possible. This will damage the main lateral tunnels, UK Coal plc
considering that the extension of the mine south through the faulting not to be viable at the
present time, there being better prospects elsewhere. DS22’ s is shown as retreating at the rate
of 12 shears per day. This is equivalent to 29,710t/w, which is in excess of that achieved todate.
DS22’ s is replaced by DS19’ s which is currently being developed. DS19’ s has a face length
of 300m and a panel run of 1,485m and with a coal in worked section of 1.95m thickness is
estimated to contain over 1.2Mt of saleable product. Phased at 10.5 shears per day working
three shifts the face has a life of some 11 months and is planned to reach exhaustion by April
2004, the face stopping short of a faulted swilley area. It must be noted that with a
considerably longer face length than DS22’ s the planned shearing rate will yield 32,000t/w,
which is well in excess of the production currently being achieved. Gas constraints may
therefore make the planned production rates difficult to achieve. DS19’ s has a third road
driven that can be used as a return enabling the tailgate to be used as a leakage intake to assist
in the control of the gas fringe. However, it is not proposed to use this roadway.
The future faces planned inbye of DS17’ s have been standardised at 300m wide and have all
been phased at 10.5 shears per day, which is equivalent to just less than 30,000t/w. The
panels have been laid out with regard to horizontal stress to give the best gate conditions for
roadway drivage.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.5.6.2
PAGE 86
Development
The schedule shows four UK Coal plc heading teams deployed throughout supplemented by a
salvage / installation team. Gate roadways, which use roof bolting as the primary means of
support, are in general phased at 50m/w. Arched roadway drivages, such as laterals, are
planned at a maximum of 30m/w. Annual development requirement peaks at around 5,700m
in 2004, reflecting the urgent requirement to open up the area in bye of D17’ s and establish
gate road drivages for DS30’ s and DS32’ s.
At present work is concentrated in completing the development of DS19’ s and preparing
DS17’ s infrastructure for driving forward to access 30’ s Area. A considerable amount of
work has still to be undertaken to make DS19’ s ready for production in May 2003. The face
heading, tailgate and connection to D17’ s all require completing. In addition DS17’ s face is
being breasted out (widened) to facilitate the salvage of the powered roof supports for transfer
onto DS19’ s.
As sections of DS17’ s AFC had collapsed the face was unable to be advanced forward to
prepare it the normal way for salvage, this has necessitated the need to widen the face by
making a roadway in front of the powered supports. This work is currently being undertaken
from the maingate end of the face. It is planned at 15m/w but due to unfavourable conditions
has only been achieving around 8m/w.
Once the remainder of DS19’ s drivages and the breasting out of D17’ s has been completed
the heading machines will be re-organised in preparation for driving forward into 30'
s Area.
The powered supports will be transferred directly from DS17'
s onto DS19'
s via the connection
road that is currently being driven. Care is to be taken when withdrawing the roof supports
off DS17’ s as it is necessary to keep the face line open to ensure a ventilation circuit for the
initial development of 30’ s Area.
In addition to the development drivages a significant amount of work is being done to up-rate
DS17’ s infrastructure. Both gate roads are being enlarged by way of dinting (removing floor
lift). It is intended to reverse the ventilation roles of the gates (intake to become return and
vice-versa) and to establish a new conveyor system. In addition it is proposed to extend the
main locomotive route into the front of the district. This will be essential to provide
acceptable machine available time within 30’ s Area.
The schedule depicts the roadways into 30’ s Area being driven as the face transfer
DS17’ s-DS19’ s is being undertaken. It is anticipated that by April 2003 the development will
have progressed to a point where both DS30’ s maingate and tailgate are being driven.
The development of DS19’ s and DS30’ s are both considered to be tight with no float.
Development of 30’ s is particularly onerous given the volume of work as outlined above
which is being undertaken in such a confined area.
4.5.6.3
Risk
The planned production rates will be difficult to achieve due to the constraints of methane gas
emissions, which increases pro-rata with the volume of coal cut. Although the number of
shears planned on future faces has reduced compared to DS22’ s the actual volume of coal cut
has increased, the shearer cutting 3,150m per day compared to 2,656m that is currently being
achieved. The longer face length may also extend the height of the relaxed area above, which
may also induce an increase in gas emissions.
The development/work programme is tight and production gaps may be induced particularly
between DS22’ s-DS19’ s and DS19’ s-DS30’ s. UK Coal plc is considering retreating DS19’ s
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 87
through the faulted swilley area to prolong its production life and cover any development
slippage. However, this may prove risky in itself.
After DS19’ s all other production is based on faces inbye of the previously worked DS17’ s
advanced face. They will therefore all be subject to risk from spontaneous combustion within
DS17’ s waste and methane intake pollution from DS19’ s, the latter being potentially a
difficult problem during periods of low barometric pressure.
D30’ s Area is at high geological risk from minor faulting, seam deterioration and washout. It
is anticipated that the seam will deteriorate, particularly in thickness as it approaches a
sandstone washout that runs along the eastern licence boundary. It is noted that the probable
reserve shown for the area within the UK Coal plc reserve assessment is 3.23Mt compared to
4.39Mt (25% relaxation) included within the mine layout and five-year production schedule.
The results of the surface seismic that is currently being undertaken is critical to the future of
the mine beyond the working of DS19’ s. The present exploration programme is planned to
reduce the geological risk in this area.
Compared to previous Deep Soft panels the face runs in 30’ s Area are rather limited resulting
in a higher frequency of face changes. In 2005 two face changes are planned impacting on
the ability to sustain annual output at around 1.3Mt.
4.5.6.4
Longer Term Plans
The Deep Soft in the south area requires significant cross-measure drivage through a
geologically disturbed area. The working of DS22’ s without a protective pillar will probably
cause significant damage to the main south laterals effectively eliminating the south from any
future development via this route.
The area to the north other than for a limited panel immediately adjacent to DS19’ s is
adversely affected by steep dips and seam thinning and would require significant crossmeasure drivage through faulting.
There is an area of Top Hard of workable thickness to the north east of 30’ s Area. It is
surrounded and limited by seam split. UK Coal plc estimates that the area contains 13.97Mt
of indicated resource. The area is remote and access would require substantial cross-measure
drivages from the current Deep Soft infrastructure. No firm layout plans have been prepared
but it is estimated that two 1,500m long rock drivages would be required. The situation is
complicated by the planned 30’ s area within the Deep Soft as it lies below the initial area that
would be accessed resulting in potential difficulties with live interaction. The development of
the Top Hard would also require a lead time of at least four years, and would have to be
started shortly to maintain continuity of production following the exhaustion of the remaining
Deep Soft. IMC have concluded that the limited resource of Top Hard available does not
support or justify the cost of investment required to complete such a major scheme
4.5.7
OPPORTUNITIES FOR FURTHER INVESTMENT
Harworth has an outline in the form of a major project to access and develop the Top Hard
Seam. However, performance has been poor and the mine has rarely ever made a profit. In
recent months there have been profits but the outlook for next year forecast further losses.
With such a background of loss making, the mine cannot be a candidate for investment unless
UK Coal plc sees potential and invests cash from Group resources or is very persuasive with
any investor or lessor.
The future of the mine relies upon the successful outcome of the exploration programme that
is currently being undertaken to prove 30’ s Area. If the area is workable it will only have
limited life and it would be doubtful whether it could support any major capital investment.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 88
Minor schemes associated with the upgrading and extension of the infrastructure through 17’ s
into 30’ s area may be considered, however, given the mine’ s current precarious situation these
must be at present regarded as Category 3.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.6
KELLINGLEY COLLIERY
4.6.1
BRIEF DESCRIPTION OF SITE
PAGE 89
Kellingley is located in North Yorkshire, 2km east of Knottingley on the A645 trunk road.
The site is bounded by the Aire and Calder Navigation Canal and is connected to the rail
network. Positioned between Ferrybridge and Eggborough the mine is well sited for ease of
access to the Aire Valley coal-fired power stations.
Shaft sinking operations started in 1958 enabling production to commence in 1965: workings
concentrated in the Beeston Seam. In the period 1978 – 1981 a major scheme was undertaken
to develop the Silkstone Seam and provide new surface coal preparation and handling
facilities. Production in the Silkstone Seam commenced in 1981 enabling the mine to
produce around 1.9Mt/a from working a combination of retreat faces in the Beeston and
Silkstone seams.
RJB Mining (latterly to become UK Coal plc) took over the mine in January 1995, at which
time the mine was in full production. In recent years production has been maintained from a
single retreat face in the Silkstone Seam producing around 1.5Mt/a.
4.6.2
MINE BOUNDARIES, OTHER SURFACE CONSTRAINTS AND ISSUES
The licence boundary is formed by the closed collieries of Fryston in the north and Askern in
the south. The recently closed Prince of Wales colliery defines the western boundary. Whilst
the boundary in the east is geological due to faulting, access further east is available into an
area of coal referred to as the Snaith Prospect.
To the south (the current Deep South area) limits are controlled by planning permission;
further reserves have been identified south of this boundary.
At Kellingley, all production has been from the Beeston and Silkstone seams. The Warren
House Seam (236m above the Silkstone) is shown in the assessment but is thinner than
similar areas of the two lower seams.
4.6.3
GEOLOGICAL ASSESSMENT OF THE MINE
Kellingley is situated on the western edge of the concealed part of the eastern Pennine Basin
coalfield. The lease comprises areas of the Silkstone and Beeston seams lying at
approximately 600m to 700m depth, and also the Winter, Stanley Main, Warren House,
Dunsil and Haigh Moor Seams. The mine is bounded by areas of the Selby Complex, and the
closed Prince of Wales, Askern and Fryston collieries. There are currently no connections
with other mines. The proposed workings are all within the planning permission area and
there is no conflict of interest in planning matters.
The Silkstone and Beeston seams are regarded as exhausted to the north and east by previous
workings at Kellingley and the former Fryston Colliery, and by faulting. To the south, the
current limits are those set by planning permission. There is mineral potential beyond this
boundary and to the south east the coal is considered to be part of the Snaith prospect.
Since production started two seams have been worked, the Beeston and Silkstone, and
production is currently from the Silkstone Seam. These seams have further working potential
in the Deep South area of the mine.
Areas of the Warren House Seam are also shown as being in the reserve statement.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.6.3.1
PAGE 90
Structure
The mine is separated into blocks by major faulting that trends north east–south west. One
major fault along this trend, the Kellington Fault, divides the mine into two areas, north west
and south east of the fault. The area to the north west can, for practical purposes, be stated as
being exhausted in the presently worked seams, whereas the area to the south east is the
current working area and is known as the Deep South Area.
A second series of faults along a west north west–east south east trend further divides the
blocks into smaller areas. The second series of faults are part of the Morley-Campsall fault
belt that was one of the main controlling structures at the time of deposition. Some of these
faults have a tendency to grow rapidly from negligible fault throws to throws in the order of
tens of metres.
In the current working area to the south east of the mine, the structure is interpreted from
workings, surface seismic, in-seam seismic data from existing drivages, and borehole
information.
4.6.3.2
Seams in Reserves
There are currently three seams shown in the reserve statement for Kellingley Colliery. These
seams are: •
The Silkstone Seam, currently being worked, is at around 670m deep and contains
6.899Mt of reserves and 11.773Mt of resources.
•
The Beeston Seam, which is 50m below the Silkstone and has a similar section, contains
1.745Mt of reserves and a further 18.920Mt of resources
•
The Warren House Seam, lies at approximately 400m depth, with a resource of 18.148Mt.
Silkstone Seam Characteristics
The Silkstone Seam at Kellingley equates to the Thorncliffe/Wheatley Lime Seam of the
wider coalfield. In general the seam is between 1.90m and 2.00m thick with normally 0.25m
to 0.40m of dirt included in the section in two or three distinct bands. This leaves between
1.60m to 1.75m of coal in the section. However within the Deep South block and south west
of 306'
s, the seam thickens. Over the last face in the south west, the middle dirt thickens
significantly, until the Thorncliffe and Wheatley Lime seams can be identified separately. The
Wheatley Lime generally deteriorates in quality as the dirt thickens. On this last face (309'
s)
the maingate drivage has confirmed the split.
Within the planned area (400 series panels), both dirt and coal thicknesses increase, giving an
overall seam section up to 2.50m. A complex and variable swilley affects the outbye end of
401'
s and anomalous seam gradient, thickness and quality are associated with this feature.
Over the East Silkstone Reserve Area, seam thickness is generally expected to be about 200
cm, with up to 0.50m of in seam dirt. However, the boreholes drilled during 2001 indicate a
thinning of the whole seam towards the east. The majority of the reduction appears to be in
the dirt content and coal thickness remains close to 1.50m.
In zone D1, the overall section at 307’ s proposed face start position could be as much as
2.60m with up to 0.90m of in seam dirt. In addition there could be the development of a layer
of cannel and inferior cannel in the lower portion of the seam.
The Silkstone roof normally consists of thin mudstone overlain by siltstone and silty
mudstone. The floor generally comprises a thin mudstone seatearth, overlying strong/locally
strong siltstone that has a high frictional ignition risk. Towards the southwest a weak
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 91
mudstone seatearth above a thin floor coal develops, reducing the frictional ignition risk in the
immediate 0.20m of floor. The thickness of soft floor is likely to increase to the south-west.
Beeston Seam Characteristics
Boreholes drilled during 2001, in the eastern reserve block, confirmed the presence of a large
area of Beeston with a thickness in excess of 2.30m. The Beeston Seam in this area, although
outside the current plan, is expected to be worked before the Silkstone Seam
The roof has weaker silty mudstone than that overlying the Silkstone Seam and forms a better
working roof to the faces.
No details are available for the floor measures but faces worked in the Beeston Seam have
had few floor problems.
Warren House Seam Characteristics
The Warren House seam is thin in comparison to the two lower seams. The seam section
ranges from 1.30m to 1.70m with two persistent dirt layers over the area of the resource. The
upper layer ranges between 0.03m and 0.10m and lies 0.40m from the top of the seam, the
lower layer is generally thicker and ranges between 0.07m and 0.25m at between 0.10m and
0.20m from the base of the seam.
The roof is weak mudstone that falls readily when the seam is extracted. UK Coal plc are
showing some 0.30m of this roof being extracted if the seam is ever worked, to alleviate this
problem. The floor to the seam is a weak mudstone seatearth with coaly streaks.
Seam Qualities
Silkstone Seam
In general whole seam ash is likely to vary between 20-25% and seam less dirt ash, 7-9%
In the current working area sulphur values are likely to be in the order of 2.1%, however
locally higher figures (2.8%) are expected. Sulphur values within the planned area will
generally be slightly higher, ranging from 2.3-2.6%.
Chlorine values will be in the order of 0.4% to 0.5%.
Beeston Seam
Information from the 2001 boreholes confirms seam thicknesses of 2.40m, although
increasing to over 2.80m in the north, as the seam splits and deteriorates.
Whole seam ash values of 14 to 16%, seam less dirt ash 11 to 12%, and chlorine 0.3 to 0.4%
are similar to those previously expected.
Sulphur was however higher than anticipated at 2.7 to 2.8 %, increasing in excess of 4%
towards the north.
Warren House
The mined section ash content of the Warren House is much higher than that of the lower
seams. This is due to the extraction of 0.30m of roof measures. The ranges given are
between 30 and 42% Ash. The clean coal ash however is much better than either the
Silkstone or the Beeston seams, at between 5 to 7%.
Sulphur contents of the seam are also much lower at between 1.2 to 1.9% and chlorine is
between 0.4 and 0.5%
This seam apart from the mined section ash, which will be significantly reduced by washing,
is of much better quality than the lower seams.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.6.3.3
PAGE 92
Reserves/Resources Assessment
The current UK Coal plc assessment for Kellingley Colliery is dated August 2002. Three
seams are shown in the assessment and these are those described above.
Position with regard to Reserves in 1998
The reserves/resource available at Kellingley in 1998 were as summarised in Table 4-27
below based on the knowledge at that time. These have changed up to the last assessment in
2002 in the light of more detailed information and a comparison will be made of the changes
later in Table 4-29 below.
Table 4-27
Kellingley Reserve/Resource Summary (01/07/98)
(Source: RJB Mining)
Million Tonnes
Seam
Reserve
Warren House
Resource
Total
18.148
18.148
Silkstone
8.664
13.348
22.012
Beeston
6.543
15.426
21.969
Total
15.207
46.922
62.129
Mineral Potential
Not Assessed
Position with regard to Reserves/Resources in 2002
The summary of the reserves as at July 2002 is shown in Table 4-28 below. In detail the
individual seams are described in the following sections.
Table 4-28
Kellingley Reserve/Resource Summary (01/07/02)
(Source: UK Coal)
Million Tonnes
Seam
Reserve
Warren House
Resource
Total
18.148
18.148
Silkstone
6.899
11.773
18.672
Beeston
1.745
18.920
20.665
Total
8.644
48.841
57.485
Mineral Potential
Not Assessed
Silkstone Seam
The colliery is currently working in the Deep South. This is the most attractive area of the
colliery’ s reserves lying to the south-east of the shafts. Two zones are accessed, Zone ECS
where there is one face left to work and Zone EC where one face is headed out and another is
in the process of being developed. These reserves are separated by a 20m fault (the
Kellington Fault) from earlier workings at Kellingley and are in strata known only by
boreholes and surface seismic surveys. In the Draft Five Year plan continuing development
of the Silkstone Seam in zone EC is envisaged along with one remaining zone to the north of
the Kellington Fault (zone D1). All other zones to the north of the Kellington Fault (Zones A,
C1, DW1 and D3), although shown in the reserve statement have been abandoned as remnant
coal.
Two further zones (zones ENi and ENii) are available to the north east of zone EC in the
Silkstone Seam. These zones have a seam section similar to that at present being worked but
have less favourable geology due to tectonic disturbances and also have added complications
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 93
due to the need to support major surface structures. UK Coal plc have recognised the risk of
unexpected faulting in their reserve calculations.
There are also additional resources in the Deep South area, south-westwards beyond the
approximately 20m throw Cridling Stubbs Fault (Zone Es). This zone is partly overworked
by Askern Colliery Warren House workings but it is to the south west of the seam split that
forms one boundary to the zone. In this zone there is a reduced section of 1.50m only
available. UK Coal plc currently has no intention of accessing or working this zone.
Southeastwards beyond the lease boundary, but within 2km of the current workings, there is
mineral potential not yet assessed by UK Coal plc. This could form a possible extension to
Zones Ecs, Ec and En of the Silkstone seam. It lies partly under the former Askern Colliery
mining area and partly under the area of interest of the Snaith prospect. There are indications
of faulting but it may be worthy of consideration as workings in the Silkstone progress in this
direction. There appears to be few surface restrictions. Here drilling has proved a section
similar to that being worked in the present area.
Beeston Seam
In the Deep South area, Beeston seam resources are expected to be upgraded to reserves as the
overlying Silkstone seam workings progress in the current working area (Zone Ecs). The
seam section is expected to be thinner than the Silkstone in this zone.
South-westwards, beyond the Cridling Stubbs fault, there are resources of workable thickness,
around 1.75m (zone Es), but somewhat impoverished as a result of a seam split. As stated
above, this zone is poorly proved both in terms of structure and seam continuity.
In both Zones Es and En, the Beeston Seam is more attractive in terms of thickness than the
Silkstone Seam (see table below).
Warren House Seam
In addition to the deeper seams currently being worked, boreholes have proved extensive
resources in the Warren House approximately 240m above the Silkstone. They are
structurally well proved by the underlying workings over a large area and are considered by
UK Coal plc to be at moderate risk.
Changes between Reserve Assessments
Between the 1998 and 2002 assessments there is a net loss of 4.668Mt (Table 4-29). This
differs slightly from a simple subtraction of the totals in 1998 and 2002 which give a net loss
of 4.644Mt, a difference of 0.024Mt. This difference can be accounted for by rounding errors
in the calculations.
The changes reflect the working of the last face in the Beeston Seam and five faces in the
Silkstone Seam (Deep South area). This would by itself account for a greater tonnage than is
shown, a total of 5.063Mt. Further reserves therefore have been generated as the plan to work
the coal in the Deep South area has progressed. These further reserves have mainly been
generated in Zones ECSi to ECSiv in the Silkstone Seam where the comparison is showing
increases in tonnage of some 2.853Mt. There has also been a net increase in tonnage in Zone
D1 of 0.392Mt based on layout changes, but these may be overstated.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 94
Table 4-29
SEAM
SILKSTONE
Sub Total
BEESTON
1998
2002
RESERVE (Mt)
RESOURCE (Mt) Mineral Risk Factor Block
RESERVE (Mt)
RESOURCE (Mt) Mineral Risk Factor Block
or
Zone Proven Probable Measured Indicated Potential Tect Sed
Zone Proven Probable Measured Indicated Potential Tect Sed or Panel
(Mt)
Panel
(Mt)
A
1.128
2
4
B
A
1.128
2
4
B
C1
1.018
4
2
B
C1
1.018
4
2
B
D1
0.740
3
2
P
D1
1.132
3
2
P
DW1
0.336
3
4
B
DW1
0.336
3
4
B
D3
0.784
5
2
B
D3
0.784
5
2
B
EC
1.869
4
3
B
ECi
0.977
2
2
P
ECii
0.592
3
2
P
ECiii
1.752
3
3
P
ECiv
1.401
3
3
P
ECS 0.602
2
1
P
ECS1 3.096
2
2
P
ECS2
1.029
4
2
P
ECS3
1.328
4
3
P
ECS1 0.741
2
2
P
ECS2
0.304
2
3
P
ECN
0.343
5
3
B
EN
5.358
4
3
B
Eni
1.400
3
3
B
Enii
3.468
4
3
B
ES
3.652
4
5
B
Es
3.639
4
5
B
ECE
0.729
B
3.698
4.966
13.348
1.718
5.181
11.773
C
C1
D1
D3
Ecn
Ec
Ecs
Ecs1
Ecs2
Ece
En
0.336
0.570
0.538
0.709
0.335
1.695
0.678
2.113
1.183
0.504
7.231
Es
Sub Total
I5104C
Kellingley Reserves and Resources Comparison
6.543
6.077
15.426
3
4
3
5
5
4
2
3
4
3
3
3
3
3
4
4
4
3
4
4
4
4
P
B
B
B
B
B
P
P
P
B
B
B
Change
0.392
2.853
Reason for Change
No change
No change
Additional reserves indicated by change in panel length, possibly overstated
No change
No change
Zone now based on panels and the majority of the zone is part of the 5 year
plan. ECi developed and working, Ecii being developed
-0.602
-3.096
-1.029
-0.323
Worked out
3 faces worked out
Worked out
Working zone – ECS1 nearly worked out, ECS2 being developed
-0.343
-0.490
Now part of ENii Zone, see below
Different zone shapes with additional faulting interpreted from seismic, most of
northern part of zone with subsidence constraints
-0.013
-0.729
-3.380
Recalculation of zone
Removed from assessment
Worked out
No change
Change in category
No change
Abandoned
Change in area based on faulting
Change in panel lengths due to faulting gives reduced tonnage
C1
D1
D3
0.570
0.538
0.709
4
3
5
3
3
3
B
B
B
Ec
Ecs1
2.075
2.663
4
2
4
4
B
P
-0.336
0
0
0
-0.335
0.380
-0.128
Ecs2
1.387
3
3
B
-0.300
Merged with Ece and now based on block giving reduced tonnage
3.192
3
3
3
4
3
3
3
4
B
P
B
B
-0.585
Zone now split into three zones, based on faulting. First Beeston faces to be
worked in Zone Eni
0
-1.304
No change
En
Eni
Enii
Es
1.745
1.745
1.709
6.077
18.920
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 95
Table 4-29
SEAM
Zone
WARREN
HOUSE
1998
RESERVE (Mt)
RESOURCE (Mt) Mineral Risk Factor Block
or
Proven Probable Measured Indicated Potential Tect Sed
Zone
(Mt)
Panel
I5104C
2002
RESERVE (Mt)
RESOURCE (Mt) Mineral Risk Factor Block
Proven Probable Measured Indicated Potential Tect Sed or Panel
(Mt)
Change
Reason for Change
AW
1.158
4
3
P
1.158
4
3
P
No Change
AC
AE
BW1
BW2
BCW
BE
CW
CE
DW
DC
DE
E
1.785
1.137
0.804
0.747
0.245
1.001
1.404
1.778
1.959
2.526
1.445
2.159
18.148
4
4
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
P
B
P
P
P
P
P
P
P
P
P
P
1.785
1.137
0.804
0.747
0.245
1.001
1.404
1.778
1.959
2.526
1.445
2.159
18.148
4
4
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
P
B
P
P
P
P
P
P
P
P
P
P
No Change
No Change
No Change
No Change
No Change
No Change
No Change
No Change
No Change
No Change
No Change
No Change
Sub Total
Total – All
Seams
Kellingley Reserves and Resources Comparison (Continued)
3.698
11.509
46.922
1.718
6.926
0
48.841
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 96
429000N
SHAFT SECTION
Section
cm
STRATA
Interval
Metres
Depth
Metres
LI
NE
S
BO
UN
DA
RY
RES
. ST
OR
.H
AT
CASTLEFORD 4FT.
122
WINTER.
71
264
44
308
PE
RM
IS
SI
ON
92
WARREN HOUSE.
155
DUNSIL
63
HAIGH MOOR.
86
400
41
PL
AN
NI
NG
426000N
CLE
M AX
427000N
OF
428000N
477
159
C1
A
441
36
D3
SILKSTONE
267
636
65
WORKINGS IN
BEESTON SEAM
BEESTON.
290
701
61
425000N
BLACK BED
56
762
REFERENCE
VW
SEAM CODE LETTER
670
424000N
423000N
VE
LE
S TO
I FT
L DR
BE
ES
AY
W
AD
S
IN
BE
ES
N
TO
SE
Boreholes
AM
Faults:
ii
Ec
VW
30
7
iv
Ec
670
Ec
s1
s
0cm
>5
ND
Es
Figure 4-10
I5104C
SE
EA
L
/
iii
Ec
E
ON
T
S
LK
SI
&
ON
ST
E
BE
AM
SE
Agreed Pillars
Site of Special Scientific Interest
Possible Area of Restriction
1/2 Depth Line
Listed Buildings
(Details available from Colliery Survey Office)
Y
AR
D
UN
BO
Askern Colliery
SEAM
FACE
2002
2003
2004
2005
2006
SILKSTONE VW305
VW306
VW401
VW309
VW402
VW307
VW403
VW405
VW406
Warren House Workings
Average Depth 450m B.O.D
UK COAL MINING LTD
COLLIERY OPERATIONS
KELLINGLEY COLLIERY
SILKSTONE SEAM
461000E
460000E
459000E
458000E
457000E
RECOVERABLE RESERVES
456000E
453000E
452000E
451000E
450000E
449000E
448000E
447000E
446000E
417000N
454000E
NG
NI
N
A
PL
ON
SI
S
I
RM
PE
455000E
418000N
iii
Ec i
ii
Ec
R
FO
419000N
300T
1000T
Horizontal Bunkers
i
Ec
9
30
VW
BA
s2 DIRT
Ec LIME
420000N
5
10
Strata Bunkers
D1
Y
LE
AT
HE
W
Dw1
2.3
Projected from Surface Seismic
Fault throws shown in Metres
D1
422000N
421000N
Proven
Projected
Enii
N
TO
750
RO
Eni
REFERENCE : KELL 03/001
0
DATE JUNE 2002
SCALE : 1/10,000
500
1000m
Kellingley Colliery: Silkstone Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 97
429000
SHAFT SECTION
BO
UN
DA
RY
PE
RM
IS
SI
ON
T
ES
CR
FA
UL
T
Seam <150cm
OF
KN
OT
TI
NG
LE
Y
264
C1
D3
86
400
441
36
477
267
636
65
BEESTON.
290
701
61
56
762
REFERENCE
SEAM CODE LETTER
Se
am
on Swilley
Projected Line of Beest
ON
GT
IN
L
L
KE
En
T
UL
FA
Eni
Faults: Proven
Projected
Projected from Surface Seismic
Fault throws shown in Metres
Ec
Ecs1
Ecs2
419000
Es
418000
NG
NI
N
A
PL
ON
SI
S
I
RM
PE
Y
Boreholes
Enii
STU
BBS
FAU
LTS
417000
HAIGH MOOR.
BLACK BED
Sea
m<
150
cm
420000
63
LT
FAU
Sp
lit
>5
0c
m
155
SILKSTONE
GH
OU
OR
GB
EG
D1
CR
IDL
ING
308
159
D1
Be
es
ton
WARREN HOUSE.
DUNSIL
.
BOW
ERS
HOU
SE F
AUL
T
AN
TI
CL
IN
E
<1
50
cm
FA
UL
T
CA
RL
ET
ON
BS
UB
ST
NE
LA
422000
Lo
w
71
41
TS
UL
FA
423000
421000
122
WINTER.
92
cm
150
m<
Sea
425000
To
p/
CASTLEFORD 4FT.
m
<150c
Seam
426000
424000
Depth
Metres
44
PL
AN
NI
NG
427000
Interval
Metres
AT
SS
RE
C LE
ST
OF
O R.
.H
NE
LI
MAX
428000
Section
cm
STRATA
/
E
AS
LE
R
FO
Y
R
DA
N
U
Sea
m<
150
BO
E
ON
T
S
LK
SI
&
Strata Bunkers
ON
ST
E
BE
AM
SE
300T
1000T
Horizontal Bunkers
Agreed Pillars
Possible Area of Restriction
LEE L
ANE
FAULT
1/2 Depth Line
SEAM
cm
CR
OS
S
FACE
2001
2002
2003
2004
2005
HI
LL
FA
UL
T
UK COAL MINING LTD
COLLIERY OPERATIONS
KELLINGLEY COLLIERY
BEESTON SEAM
RECOVERABLE RESERVES
Figure 4-11
I5104C
462000
461000
460000
459000
458000
457000
456000
455000
454000
453000
452000
451000
450000
449000
416000
448000
REFERENCE : KELL 03/002
0
DATE JULY 2002
SCALE : 1/10,000
500
1000m
Kellingley Colliery: Beeston Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
T
UL
FA
E
SS
RE
. ST
OR
BO
W
ER
S
RY
DA
UN
BO
ION
ISS
RM
PE
425000N
T
UL
FA
CT
RA
F
E
LT
NT
AU
F
PO
H
CT
RT
RA
F
NO
E
NT
PO
H
UT
423000N
SO
ON
ET
L
R
CA
FA
UL
T
T
UL
FA
BCE
CE
BCW
AW
S
BB
U
ST
NE
LA
BW1
FA
UL
T
63
400
T
UL
FA
86
441
6
447
267
636
65
BEESTON.
290
701
61
BLACK BED
56
762
REFERENCE
Y
SEAM CODE LETTER
DE
Boreholes
Faults:
Proven
Projected
Projected from Surface Seismic
T
UL
FA
Fault throws shown in Metres
1/2 Depth Line
R.J.B. MINING (UK) LTD
COLLIERY OPERATIONS
KELLINGLEY COLLIERY
WARREN HOUSE SEAM
FA
UL
TS
Askern Colliery
Warren House Workings
Average Depth 450m B.O.D.
RECOVERABLE RESERVES
DATE JULY 2002
458000E
5
457000E
453000E
452000E
Figure 4-12
ST
UB
BS
S.S.S.I.
Possible Area of Restriction
RY
DA
UN
O
B
ION
ISS
M
ER
GP
NIN
N
PLA
FAU
LTS
451000E
450000E
449000E
155
SILKSTONE
E
Prince of Wales Colliery
Warren House Workings
448000E
WARREN HOUSE.
DUNSIL
.
HAIGH MOOR.
Site of Special Scientific Interest
420000N
I5104C
308
Agreed Pillars
CR
ID
LIN
G
419000N
264
189
456000E
T
UL
FA
71
41
455000E
ON
ET
RL
CA
421000N
122
WINTER.
Depth
Metres
DC
CW
454000E
CR
IDL
ING
STU
BBS
CASTLEFORD 4FT.
Interval
Metres
92
DW
422000N
Section
cm
44
ON
GT
N
I
LL
KE
BW
2
424000N
AC
BE
KN
OT
TI
NG
LE
Y
ING
NN
PLA
CT
RA
F
E
NT
PO
HO
US
E
Y
AR
ND
OU
NB
SIO
MIS
PER
426000N
GH
OU
R
T
SHAFT SECTION
STRATA
ING
NN
PLA
AE
427000N
T
UL
FA
T
EA
CL
H
X.
MA
F
O
IRY
FA
428000N
T
UL
FA
L
HIL
LIN
M
RA
Y
B
PAGE 98
0
NOT TO SCALE :
500
1000m
Kellingley Colliery: Warren House Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.6.3.4
PAGE 99
Exploration
Within the current Draft Five Year plan no further surface exploration is planned by either
borehole or geophysical methods. However in-seam seismic surveys will be used on a routine
basis where appropriate to confirm the structure. Boreholes to prove the Beeston section are
expected to be required periodically from the Silkstone workings. Prime locations are the
inbye end of 402’s and the junction between Whitley south and east drivages. Pillar samples
are also expected to provide information on seam quality variations within the present block
and eastern reserves area.
4.6.3.5
Other Seams of Interest
There are no other seams of interest at Kellingley.
4.6.3.6
IMC Commentary on the Reserve/Resources at Kellingley Colliery
The planned workings at the mine are all in the Deep South area in both the Silkstone and
Beeston Seams. In the Silkstone Seam reserve/resource zones shown in the north part of the
mine no longer have access and are now abandoned. These zones are Zones A, C1, D3, and
DW1 and these are shown as Indicated Resources on the current UK Coal plc Assessment.
There is a case, based on the fact that there is no intention to work them, for moving these
zones into the Mineral Potential category or in abandoning them altogether and removing
them from the assessment, although they do meet the criteria of Indicated Resource. Similar
comment can be made for Zones C1 and D3 in the Beeston Seam, both of which have been
abandoned.
It is the opinion of IMC that all zones at the Colliery are assessed correctly. It is noted that
Zone D1 (Silkstone) has been assessed on panel length. The panel as shown on the plan will
damage the main infrastructure in the Beeston at the mine as UK Coal plc believe they will
not be required to support further planned working.
Taking the above comments into consideration the table below indicates IMC’ s assessment of
the reserve/resource at the mine.
Table 4-30
IMC Reassessment of Kellingley Reserve/Resource Summary (01/07/02)
Million Tonnes
Seam
Reserve
Resource
Total
Warren House
Mineral Potential
18.148
Silkstone
6.899
8.507
15.406
3.266
Beeston
1.745
17.641
19.386
1.279
Total
8.644
26.148
34.792
22.693
Finally, IMC and UK Coal plc both consider that there are further areas to the south east of
the present mining licence boundary that could be available to the mine in both the Beeston
and Silkstone seams. These areas are where the structural geological coverage is limited to
surface seismic surveys and boreholes. However, for some part, overworking in the Warren
House Seam by Askern Colliery has indicated a fault pattern and intensity that could be
extrapolated down to the lower seams.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.6.4
PAGE 100
MINE CHARACTERISTICS AND CONSTRAINTS
The production areas at Kellingley are defined in blocks by SW/NW faults. This has resulted
in a rather complex infrastructure leading to the present developments in the Deep South. In
addition, infrastructure roadways have been driven at two different horizons both in the
Silkstone and Beeston seam some 65m below.
Shaft winding capacity is rated at 2.25Mt saleable at a vend of 60%. Present production
outputs are planned at 1.6 to 1.7Mt/a and are well within the shaft capacity. Limits on output
are more related to the adoption of a single face strategy together with its associated operating
time.
In their need to reduce costs UK Coal plc have adopted a single face strategy. The working
areas have been rationalised with activities now confined to the Deep South. Long-term
strategic drivages to access face replacements have achieved only limited progress, almost a
‘just-in time’ scenario. Additionally, the company recognises that there is an urgent need to
review the present planned layouts. If the market permits there maybe scope to examine a
different production strategy in the drive to reduce costs per GJ. This approach would be
aimed in increasing saleable output to 2.0Mt, which is still within the shaft capacity at the
mine. To achieve this output would probably require operating two production faces for
extensive periods during the year. It would also require operating the mine with an increased
manpower at a level of around 700 men.
Kellingley Colliery has for many years continually achieved high performances. This year
with one face and six development teams it is now expected to achieve an annual output of
1.6Mt. At the end of October 2002 it was 121,000 tonnes below budget. Next year the mine
is faced with additional costs of two face changes during the year.
As observed underground, the standards of both main strategic and gate roadways are good.
The strategic developments have, in the past, been driven on steel arches. It is now planned to
replace the arches with roof bolts in the main access roadways being driven in the Deep
South. It is hoped to both improve the rates of drivage and reduce costs. This is particularly
so with the present drivages being sited in the best direction with respect to stress, conditions
seen through the mine indicate that this strategy has every chance of success. Certainly,
observations in the gate roadways demonstrate that conditions are directional. Higher density
roof bolting patterns are required to stabilise the roof of the roadways aligned in the worst
direction regarding maximum principal horizontal stress. In addition, these roadways indicate
more rib movement and floor lift. In reviewing their long term plans UK Coal plc are well
aware of the need to lay out future longwalls in the best direction whenever possible.
Since the production area is extending further south, increased reliance will be placed on
efficient manriding and materials facilities. Consideration is being given to improving the
long-term standards of the rail track to effect a substantial increase in locomotive speeds. As
the conveyors are installed in the south, consideration may also be given to two-way
manriding.
As the new areas in the south are developed, re-introduction of FSV’ s may be considered.
These are much more flexible than pony locomotives and as such are more adaptable to face
salvages and installations. Kellingley has two sets of face equipment. If development
progress was sufficiently advanced it would allow for the installation of equipment on the
replacement face before the working face ceases production, resulting in continuity of output
and major cost savings. The flexibility of FSV’ s would assist in these operations.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.6.4.1
PAGE 101
Ventilation
Over the next few years, mining operations will take place in the Deep South section of the
mine in the Silkstone seam. This area is split into the West side (Cridling) and the East side
(Whitely) areas. At the end of 2004 the West Side production should finish and will be
sealed.
Currently, VW307’ s face is planned to retreat close to main infrastructure roadways in the
Beeston Seam, which could be used to support future working faces for the longer term in the
Deep South Area. It is IMC’ s opinion that it may therefore be beneficial to maintain this
infrastructure. To reduce risk and damage to these roadways, it would therefore be prudent to
cease production early on VW307’ s and leave a pillar of for protection.
The East Side (Whitely District) will rely on a booster fan to provide ventilation into the
future for both Silkstone and Beeston seam workings. The main concern is the single intake
(Kellington) that will then exist, and it has been suggested that a further parallel intake might
be needed. Consideration should be given to utilising the Kellington return if the problems of
pollution from previously worked sealed areas can be overcome by the use of methane
drainage from the sealed off areas in the district.
The benefits of the Booster Fan installation in early 2003 will not be realised until 307’ s
finishes production at the end of 2004.
4.6.4.2
Subsidence
Silkstone Seam
Reserve Zone D1: 307’ s Panel is shown on the five-year development plan to work in the
south part of this area. No mining has yet been planned for the north part of the area.
There is a large ash disposal works including lagoon and tip in the area where ash from
Ferrybridge and Eggborough Power Stations is disposed. The M62 Motorway crosses the
north end of this area.
Subsidence from the planned panel is estimated to be some 40 pence/t. Should a panel work
in the north part of this area, subsidence damage costs would be considerably higher.
Reserve Zone ECS2: This is shown on the five-year development plan to be the working of
309’ s Panel.
This panel will work beneath low-lying land and with minor damage costs but no buildings
will be affected. Subsidence damage costs will be low at less than 10 pence/t.
Reserve Zone ECi and Ecii: The five-year development plan shows that these areas will be
mined by 401’ s and 402’ s panels.
The M62 Motorway will be affected by these panels including the interchange for the A19.
The Aire and Calder Navigation will also be affected. The village of Whitley will be directly
undermined.
Subsidence damage costs for this area are high and estimated to be around £1.50/t.
Reserve Zone ECiii and Eciv:
405’ s, 406’ s and 407’ s Panels are shown in area ECiii
with 405’ s and 406’ s in the five-year development plan. 403’ s Panel is in area ECiv and is
included in the five-year development plan.
Whitley and High Eggborough villages will be affected by working in these areas. Of greater
importance, however, are the M62 Motorway the Aire and Calder Navigation including locks
and the Knottingley-Goole railway. Subsidence damage costs are anticipated to be around
£1.25/t.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 102
Reserve Zones Eni and Enii:
The power station and adjacent sewage works are in
these areas, as is Hensall village. The M62 Motorway crosses the south part of area Enii with
the Knottingley-Goole railway sensitive to mining, which could take place in both areas. In
addition, and of great significance, is the East Coast Main Railway line passing through both
areas. There is also a Glass Works.
It is clear that limitations will be imposed on mining layouts, which are likely to include a
Counter Notice from Network Rail. On the assumption that these major structures will not be
seriously affected, then subsidence damage costs are estimated to be around £1/t.
Beeston Seam
Reserve Zone D1: As for D1 in the Silkstone Seam, the main points of concern are the ash
disposal works and motorway.
Subsidence damage costs are normally higher for mining in the Beeston Seam, and costs in
excess of 50 pence/t can be anticipated. As before, if mining were to take place in the north
part of the area beneath the motorway, subsidence damage costs could be considerably higher.
Reserve Zone Eni: Two panels have been planned for this area although neither is shown
on the five-year development plan.
These panels are shown not to encroach on the power station area but they would undermine
the Knottingley-Goole railway.
Subsidence damage costs are estimated to be around 50 pence/t.
Reserve Zone En: The power station overlies this area, as does Hensall village. The
Knottingley-Goole and East Coast Main railway lines could also be affected by mining in this
area.
Subsidence damage costs could be in excess of £1/t and considerably greater if major
structures were affected.
4.6.4.3
Coal Preparation Facilities
The plant was built in the early 1980’ s as a twin stream system capable of treating around
1000t/h, which was subsequently reduced to a single stream plant in the early1990’ s. It now
has a design capability at around 650t/h and is sensitive to stoppages as a single stream plant.
The ROM from the shaft goes to a stockpile. Feed to the plant is extracted from the base at a
controlled rate going to a scalping screen. Screen oversize is processed in a three Product
Large Coal Dense Medium Separator, a Wemco Drum. The clean coal produced satisfies the
domestic market, the middlings are crushed and added to the Power Station Fuel (PSF) Blend,
with the discard going to the tip.
The underflow from the scalping screen feeds to a dry fines extraction screen. The underflow,
being the dry constituent of the PSF blend, is fed into a bunker. The oversize product from the
screen, together with any excess dry fines is fed to a Baum Wash Box. The wash box
produces cleaned coal and a discard, which goes to the tip along with the coarse discard from
the Dense Medium separation. The clean coal from the box is dewatered and screened into
two fractions, singles and washed smalls. The singles can either be out-loaded as a product or
added into the blending system producing the PSF blend, and a washed smalls which is
dewatered then bunkered for blending with the dry fines forming the basis of the PSF.
The wash box operates with a conventional water circuit. The overflow from the tower
provides the wash water for the wash box; the underflow is fed to a slurry screen. The
overflow from the slurry screen joins the washed smalls to be centrifuged prior to addition to
the PSF blend. The underflow from the slurry screen is the feed to the froth flotation section
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 103
of the plant. The recovered froth is dewatered on a vacuum filter; the recovered filter cake is
added to the PSF blend.
The tailings from the flotation plant gravitate to a thickener; the top water being decanted and
reused as process water. The thickened sludge from the base of the thickener is pumped to
filters before being layered into the colliery tip.
Domestic sales accounts for between 6 & 8% of the saleable products, breakages from the
domestic products are also added to the PSF Blend.
The major part of the PSF is despatched by rail, with the remainder by road; a barge facility is
no longer being used but is still in place.
The plant should have a potential of processing around 70,000t/w based on 100 hrs of
availability. The bottleneck in the process appears to be the fines treatment section of the
plant, in an attempt to rectify the situation the fines treatment plant from Prince of Wales is
being transferred to Kellingley. The current ROM production is around 50,000 to 60,000t/w,
with a 65% vend. Currently there is 540,000 tonnes of ROM on stock together with 140,000
tonnes of PSF.
4.6.5
4.6.5.1
HISTORIC PERFORMANCE
Production
Table 4-31
4.6.5.2
Historical Production Performance at Kellingley
Kellingley
1999
2000
2001
Actual Output
million tonnes – saleable
1,374
1,469
1,513
Budgeted Output
million tonnes - saleable
1,620
1,400
1,600
Difference
million tonnes - saleable
-0.246
+0.069
-0.087
Development
Table 4-32
Historical Development Performance at Kellingley
Kellingley
1999
2000
2001
Actual Developments
metres
6,194
6,842
8,280
Budgeted Developments
metres
8,141
7,413
9,512
Difference
Metres
-1,947
-571
-1,232
Production and development throughout the period has been affected by minor faulting. This
was particularly prevalent in the development and working of VW303’ s and VW304’ s.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.6.6
PAGE 104
PRODUCTION AND DEVELOPMENT FORECASTS
4.6.6.1
Production
The Kellingley Colliery five-year plan is currently under review by UK Coal plc and is
subject to change, particularly with regards to the layout of faces to the south east of the
current working area that are planned to be worked from November 2004 onwards. The
following description is based on the Draft Five-Year Plan prepared in October 2002 albeit
that it is recognised that this has not been approved by UK Coal plc and is being reviewed.
The Draft Five Year Production Schedule is as follows:
Table 4-33
Face
Tonnes
in Panel
Draft Five Year Production Schedule
2002
2003
2004
2005
2006
Development (metres)
6,226
9,441
9,125
10,080
6,691
Total Output (Mt)
1.638
1.700
1.612
1.656
1.815
Silkstone
VW306
1,364,000
VW401
1,061,000
VW309
382,000
VW402
666,000
VW307
961,000
VW405
936,000
VW406
745,000
VW407
539,000
VW403
1,888,000
Output is planned to continue to be produced from a single retreat face in the Silkstone Seam
within the Deep South Area. Two sets of face equipment are utilised to avoid gaps in
production. Annual production levels are projected to be around 1.6Mt to 1.8Mt.
Kellingley has successfully worked a succession of six Silkstone faces within the Deep South
area since October 1997. From September 1998, the mine has operated a single face strategy,
producing around 1.6Mt. Prior to this a two-face strategy was maintained working separate
areas from a combination of panels in the Beeston and Silkstone seams, producing around
2Mt/a.
The current area of Silkstone faces accessed from the Kellington Intake and Return is
reaching exhaustion. Three longwall panels remain to be worked that are parallel and
adjacent to the previously worked faces, namely VW401’ s and VW402’ s to the north east and
a small panel, VW309’ s to the south west close to the Cridling Stubbs boundary faults. It is
planned to work these faces in the period to March 2004.
It is important to note that following this period it was originally envisaged that replacement
faces would then be worked in the same area in the Beeston seam below. Unfortunately
underground boreholes have proven that in the bulk of the area, the seam is thin at around
1.30m inclusive of dirt bands. This has necessitated the need to extend the Silkstone
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 105
infrastructure to the east and south to secure future face room as an alternative to working the
Beeston seam. (Figure 4-11)
Following VW402’ s, continuity of production will then be provided by VW307’ s, which is a
310m wide panel that is to be worked in a SW-NW direction just north and parallel to the
Kellington Fault. The face is currently being accessed and its maingate will connect directly
into the main J2 Connection Tunnel, which will provide intake air and mineral clearance. The
inclusion of this face is important to maintain continuity of production whilst the Silkstone
infrastructure in the form of two lateral tunnels is extended southeast to access future faces. It
is intended to maximise the face run of VW307’ s by working it out over the existing access
tunnels in the Beeston seam below. These tunnels provided the original access into the
Silkstone Deep South and currently provide supplementary ventilation and means of egress.
The working of VW307’ s can be expected to damage these infrastructure roads leaving the J2
Connection Tunnel which houses the main locomotive system and trunk conveyor as the sole
Intake Roadway into the Silkstone Deep South.
Following VW307’ s the present draft plan shows three faces being worked beyond the current
panels in a triangular shaped parcel of coal. The area is bounded to the north west by the
previously worked faces terminating against a 3.5m fault, to the south by the Lee Lane Fault
that runs in almost an east-west direction and to the north east by the Whitley South Lateral
tunnels that are to be driven to access the faces. Following these faces it is intended to work
VW403’ s face to the east side and parallel to the Whitely South Laterals. VW403’ s is
currently shown to work through the 3.5m fault, the exact direction and size of which will
first be proven by the Whitley South Laterals. It is recognised that the final layout of
VW403’ s will be determined following the proving of this fault. It is the layout of these faces
following the working of VW307’ s that is currently subject to review.
The faces are generally planned at 277m wide, the exceptions being VW401’ s (230m),
VW309’ s (210m), VW307’ s (310m) and VW403’ s (310m). Working three shifts the faces
are planned at between 13.5 shears (VW403’ s) and 19.5 shears per day (VW309’ s). This
equated to output levels of between 7,276t/d and 8,226t/d. These high rates of retreat give the
faces very short lives of only 3 to 8 months, except for VW403’ s, which is at present assumed
will work straight through the aforementioned anticipated faulting. This results in two face
changes taking place in each year and an onerous development programme that peaks at over
10,000m in 2005. It must be noted that on average the panels have much shorter runs than
those enjoyed in the Silkstone since the adoption of the single face strategy and are much
more akin to those experienced when the mine was operating two faces.
4.6.6.2
Developments
Six development teams are employed throughout the five-year plan, consisting of five UK
Coal plc teams supplemented from one manned by outside contractors. At the end of 2002,
two teams were employed to completing the blocking out of VW309’ s, one team to the initial
access of VW307’ s, one team to the cross-gate for VW402’ s and two to the main Whitley
South strategic drivages. Upon completion of VW309’ s development the teams will be
transferred to VW307’ s and VW402’ s.
Gate roads use roof bolts as the primary means of support and are in general phased at 75m/w
and the face lines at 45m/w. The main Whitley South lateral tunnels are currently being
driven using arches and are planned at a maximum of 50m/w. Once the Whitley South lateral
tunnels are turned into their final south-easterly direction it is intended to use roof bolts as the
primary means of support to enable drivage rates to be enhanced.
The development plan is onerous, over 9,000m having to be completed in both 2003 and 2004
and over 10,000m in 2005. This will be a significant increase over that achieved in 2002
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 106
(forecast to be 6,226m) which is also typical of previous years. This reflects the development
effort that is required to ensure that continuity of production is maintained bearing in mind
that the faces are of relatively short life and phased to retreat at up to 68m/w. It also reflects
the relatively low yields of the faces with a typical coal in worked section of around 1.77m,
and the extensive strategic development that is required to access the faces to be worked after
VW307’ s.
In the short term, the development of VW307’ s is very demanding. An access circuit is
currently being driven and is to be completed by May / June at the latest. This will only give
7 – 8 months to complete the drivage of both gate roads and the face line. The gate roads,
which are just over 1,300m long are phased at 65m and 75m/w. The gate roads will be driven
in a south westerly direction which will not give the best conditions adding pressure to the
developments.
4.6.6.3
Risk
The face runs are limited resulting in at least two face changes each year.
The development programme is very demanding with no float, any slippage will therefore
potentially manifest itself in face production gaps. The gate roads for VW307’ s, VW405’ s,
VW406’ s and VW407’ s are not in a favourable direction for drivage, the planned
development rate of 75m/w may therefore be difficult to achieve.
In reviewing the five year plan there appears to be an urgent need to ensure that sufficient
time is made available to develop further faces to the south and east. It is also necessary to
extend the present infrastructure to satisfactorily support these future faces.
It is of concern that the layout of the faces for production beyond November 2004 have not
yet been finalised.
4.6.6.4
Longer Term Plans
As outlined above the layout of faces for production beyond November 2004 has not been
finalised. However, various options for the access and working of future faces to the north
east of the current working area is being examined in both the Silkstone and Beeston seams.
Options include the development of laterals in a north east direction passing just south of
Eggborough Power Station. This would require the negotiation of some steep seam gradients
and faulting. Substantial rock drivages would be required to negotiate the Eggborough Fault,
although the 40m throw will assist in facilitating the transfer from Silkstone into the Beeston
seam which thickens towards Eggborough Power Station.
Further to the south there is the potential for driving a pair of lateral tunnels just within the
Planning Permission Boundary, parallel to the drivages as outlined above. UK Coal plc have
also indicated that they are looking towards applying for an extension to the Planning
Permission Boundary to the south.
In all instances development of face room to the east and south will have to take cognisance
of a relatively high intensity of faulting and a significant number of subsidence sensitive
features including the Knottingley-Goole Canal, M62 Motorway, Glassworks and
Eggborough Power Station.
4.6.7
OPPORTUNITIES FOR FURTHER INVESTMENT
Of all the mines in the UK Coal plc portfolio, this is the only one with a consistent track
record of unbroken profit. Over the years, it has been a significant earner for both British Coal
and UK Coal plc. In terms of cash, it has also a virtually unblemished record- save for the
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 107
current year where there is a deficit, as at the end of October. This is because the mine has
increased stocks that are growing.
One capital scheme already committed by the company is to refurbish and upgrade the coal
preparation plant to deal with the current level of production. This is planned to come on
stream next year. Further, the mine has already engaged in some capital drivages to access
new areas of coal. The cash implications of this are not included in the above analysis.
However, the mine has been a solid performer and future schemes are likely.
In 1998 Kellingley rationalised its underground mining activities and adopted a single face
strategy. After previously operating the mine with outputs of 2.0Mt/a, over the past four
years the output has fallen to an average of 1.5Mt/a. A note of caution is also highlighted in
the delay in being able to finalise an acceptable production plan including future panel
layouts. UK Coal plc is aware of this and is in the course of reviewing its present plans.
As the mine develops areas further to the south in the Silkstone Seam and to the east in the
Beeston Seam it will have to both maintain and extend its existing infrastructure. Thus in
planning longer-term production increased levels of investment will be required with schemes
previously described. Operating at outputs of 1.4Mt/a may not generate sufficient income and
resulting operating profits to support all these requirements. Therefore, since the present plans
and future layouts have been recognised as in need of review the UK Coal plc may also need
to examine its present production strategy. Changes in the latter being related to a possible
need to increase output to similar levels previously achieved.
As part of the mine’ s investment programme major developments are ongoing in the Whitley
area of the mine. Further extensions south and east to access both Silkstone and Beeston
seams will be necessary to extend production beyond the five-year period. Although fiveyear plans have still not been finalised future cross-measure drivage will have to be
undertaken if the thicker Beeston seam is to be worked to the east. These developments may
well benefit from an investment scheme (Category 2).
Additional Category 2 projects could emanate from the above expansion of the mine
infrastructure to the south and east. The locomotive system will require extension with the
possibility of up-grading to high-speed and mineral conveyors will require installation. In
addition the change in the geological structure with the need to negotiate steeper seam
gradients and faulting may require the installation of alternative supply systems with
transhipment stations from the locomotives. Additional booster fans may also be necessary to
maintain ventilation. It is possible that the roadway development and aforementioned
associated work could be prepared and considered as a single major project.
Immediate improvements to the coal preparation facilities are being undertaken to overcome
the imbalance in capacity to that of the mine. However, it is possible that further investment
may be needed in the plant.
The production plans include for a replacement set of face equipment. It is likely that these
will be sourced from elsewhere within the company albeit they will probably require major
overhaul. This expenditure is regarded as Category 1.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.7
MALTBY COLLIERY
4.7.1
BRIEF DESCRIPTION OF SITE
PAGE 108
Maltby is situated in South Yorkshire, some 12km east of Rotherham on the outskirts of
Maltby town. It lies adjacent to the A631 and about 5km from Junction 1 of the M18
motorway. The mine is connected to the rail network.
Maltby Colliery was established between 1907 and 1911 since when the Barnsley, Swallow
Wood, Haigh Moor and Parkgate seams have been worked. The Barnsley seam was worked
from mine inception until 1972 when it reached exhaustion. The Swallow Wood seam was
worked from 1969 to 1993 when it ceased due to a change in mine strategy. The Haigh Moor
seam was worked in 1978 and 1979 but abandoned due to bad roof conditions.
Maltby has three shafts, No.1 and No.2 are 6.1m in diameter and No.3 is 8m. The shafts are
804m, 984m and 991m deep respectively.
In 1981 a major reconstruction, the Parkgate Project, was undertaken to access reserves in the
Parkgate Seam. The new No 3 shaft was sunk and commissioned in 1989 and No 2 Shaft was
deepened to the new horizon. Production from the first Parkgate face started in 1992.
The main colliery site covers some 33 hectares and has comprehensive facilities including a
coal preparation plant and coal stocking areas. In addition there are some 124 hectares of land
used for spoil tipping and a further 21 hectares of other non-operational land.
In May 1993 production temporarily ceased and the mine was placed on a development only
status to establish longwall retreat mining within the Parkgate Seam. At the time of
privatisation production was due to re-commence in September/October 1994. At the same
time the neighbouring Silverwood Colliery was closed and its reserves transferred to Maltby.
Since privatisation RJB Mining (latterly to become UK Coal plc) have concentrated
production in the Parkgate Seam.
4.7.2
MINE BOUNDARIES, OTHER SURFACE CONSTRAINTS AND ISSUES
Maltby licence area is surrounded by a number of working and abandoned mines. These
include Rossington in the north, Harworth and Thurcroft in the south east and south-west,
Kilnhurst and Silverwood to the east. The extent of future workings is constrained by seam
splits, thinning and the effects of channel sandstones in the immediate roof of the seam.
4.7.3
GEOLOGICAL ASSESSMENT OF THE MINE
Maltby Colliery is in southern Yorkshire, in the eastern Pennine Basin Coalfield. The Coal
Measures outcrop across the westerly parts of the mine area, whereas in the central and
eastern parts, they dip gently northeast beneath unconformable Permian strata. The main seam
of interest, the Parkgate, lies at depths between 580m and >950m below OD. The local Coal
Measures are typical for this part of the coalfield. Superficial deposits are not relevant to
workings at these depths. There are no igneous features of mining significance.
4.7.3.1
Structure
The mine lies in a structurally “ quiet” area between two major features: the SW-NE South
Don Fault Zone (which forms the effective northwestern boundary of the licence area), and
the Thurcroft Fault Zone (on the southeastern boundary). Much of this area contains only
minor normal faults, in zones. Throws are usually <5m, and commonly <2m. Fault
dispositions in most unworked Parkgate zones are assessed from extensive provings in the
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 109
Barnsley and Swallow Wood, 220m and 165m above the Parkgate, respectively. There is
scope for local refinement of fault sizes and positions in the Parkgate, but extrapolation
generalities are established. Few of the worked Parkgate panels have encountered faults.
The gentle Maltby Anticline strikes WSW-ENE, close to the shafts area: a BP oil borehole is
sited in the anticlinal area, east of the shafts (several small oil shows have been met in the
mine workings). Most of the Parkgate workings and reserves/resources lie on the northern
limb of the anticline, which is characterised by low northeasterly bedding dips. In the
northwest, Parkgate T106’ s unit proved bedding dips down-northwesterly, perhaps reflecting
the approach to the South Don Fault Zone.
Coal cleat strikes are typically NW-SE. The principal horizontal stress direction is NNW;
stress data are monitored through the roof bolting procedures.
4.7.3.2
Seams in Reserves/Resources
The following seams are considered for this mine.
•
Parkgate Seam
•
Thorncliffe Seam
Parkgate Seam Characteristics
Roof variations present the main mining difficulties at Maltby, the result of a large channel
sandstone/siltstone system (the Parkgate Rock) overlying the seam in various parts of the
mine. This gives support problems, and in the west and east, the seam is locally washed out.
The immediate roof is commonly a very weak mudstone known as “ clod” , and this tends to
fall into the mined section. A belt of thick mudstone trends northeasterly across the eastern
parts of the mine, and this has also given local support problems; the abandonment of one
panel (T14’ s) is thought to have resulted partly from support problems within this thick
mudstone belt. Siltstones overlie the clod in most of the mine area.
The seam comprises a single coalbed, typically 1.40m to 1.60m thick, with a tendency to
thicken slightly to the west. The ash varies between 3% and 5%, and the sulphur between
1.4% and 2.0%. The higher sulphur areas tend to be towards the north. The seam has a coking
coal rank, which allows a variety of marketing outlets. The only seam variation of
significance is a belt of thin coal 0.3km to 0.4km wide, across the northern parts of the layout.
It appears to be accompanied by cannel, c. 0.1m thick, at the top of the seam. Within this belt,
the seam is locally <1m thick, resulting in the foreshortening of T08’ s panel and the deletion
of T09’ s from the mining plan.
The floor is typically up to 0.30m of mudstone seatearth. Stronger siltstones and local
sandstones lie beneath. Up to 0.40m of floor material may be extracted in the roadways. The
floor is not thought to present any significant mining problems, although there must be some
locally high frictional ignition potential when extracting any sandstones in the lower floor.
There are no cover problems.
Thorncliffe Seam Characteristics
The Thorncliffe is the only seam, other than the Parkgate, to feature in UK’ s reserve/resource
assessment. It lies some 12m to 23m below the Parkgate, and is assessed as Indicated
Resources by UK Coal plc. At Maltby, the seam is known only from boreholes. The
Thorncliffe roof is typically a mudstone, several metres thick, and is assumed strong enough
to form the working roof on faces (the UK assessment is based on full extraction). It is
significantly stronger than the Parkgate “ clod” . Sandstones with subordinate siltstones are
present in some borehole provings, and are expected to lie within narrow belts (low 100’ s m
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 110
wide), with the sandstones locally forming the immediate roof; support problems would be
met within these belts.
The Thorncliffe Seam itself comprises two main coalbeds (Low and Top Thorncliffe) that are
united, or only just split, over much of the area that includes the Parkgate workings.
•
The Low/Top Thorncliffe seam split opens to the west and north, across the western
Parkgate worked area. Beyond the split, the Top Thorncliffe is the thicker of the two
individual coalbeds, but is rarely >1m thick.
•
Where united, the seam is typically around 1.30m to 1.70m thick. The upper part is
usually mainly clean coal, the lower part is commonly inferior coal and dirt. The UK
resource assessment suggests that the ash and sulphur of likely mined sections would be
between 17% to 26%, and 2.8% to 3.8%, respectively. Seam-less-dirt ash and sulphur
contents would require detailed appraisal using all available data, prior to any mining
commitment.
•
The overall seam appears to thin, with improving quality, towards the southeastern
margins of Maltby.
The floor of the full Thorncliffe Seam is typically strong siltstones, sometimes with thin
mudstones just below the seam. No cover problems are expected.
4.7.3.3
Reserves/Resources Assessment
UK’ s assessments for January 1998 and July 2002 have been provided for this study. The
following tables summarise tonnages and classifications in these.
Position with regard to Reserves in 1998
Table 4-34
Maltby: Reserve/Resource Summary January 1998
(Source: RJB Mining)
Million Tonnes
Seam
Reserve
Resource
Total
Mineral Potential
19.308
10.404
29.712
None
Thorncliffe
None
9.248
9.248
None
Total
19.308
19.652
38.960
None
Parkgate
Position with regard to Reserves in 2002
Table 4-35
Maltby: Reserve/Resource Summary July 2002
(Source: UK Coal)
Million Tonnes
Seam
Reserve
Resource
Total
Mineral Potential
12.493
10.948
23,441
None
Thorncliffe
None
9,248
9.248
None
Total
12.493
20.196
32.689
None
Parkgate
Changes between Reserve Assessments
The difference between January 1998 and July 2002 (4.5 years) totals is some 6.8Mt. This is
compatible with the typical output of around 1.5Mt/y. These changes are shown in Table
4-36 below.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.7.3.4
PAGE 111
Exploration
Geological structure. The area is generally well proved structurally (although there is a small
area in the northeast that is unworked in any seam). No surface seismic surveys are expected.
Parkgate Seam. There is no need for further deep borehole proving of the Parkgate, the seam
trends being reasonably well, to very well established. It is also unlikely that the roof
variations would be suitably addressed by further, extensive drilling. Regarding the roof
variations, these require ongoing detailed underground logging and interpretation.
Thorncliffe Seam. It is not possible to fully evaluate the Thorncliffe without further
information. It is assumed that the existing underground borehole set at Maltby includes
several holes drilled to below the Thorncliffe, and detailed mapping is required, to either
eliminate the Thorncliffe as a viable alternative to the Parkgate, or to establish any areas
wherein it could form a local resource. In the absence of a sufficient number of existing
provings, a series of underground boreholes from the Parkgate would be necessary.
4.7.3.5
Other Seams of Interest
As noted earlier, the Barnsley, Swallow Wood, and the Parkgate seams have been extensively
worked. It is thought that some Haigh Moor (c. 15m below the Swallow Wood) has also been
worked locally. The extensive 1970’ s drilling for the Parkgate at Maltby have provided the
area with a modern data set for all seams down to the Parkgate. There is some limited proving
below to the Thorncliffe, with a few holes to the Silkstone (the Top Silkstone Seam is 70m to
80m below the Parkgate). Blyth Gate Lane Borehole, on the southeastern limit of the Maltby
licence area, proved seams below the Silkstone to the Whinmoor and Kilburn, after
intersecting the Thurcroft Fault.
The surface borehole set is supplemented by many underground boreholes. These were drilled
mainly from Maltby, and Yorkshire Main Colliery to the north.
The borehole data have been searched for any seams that are 1.50m or thicker, in the Maltby
area. The following notes refer to this data search.
•
The Wheatworth Seam is an inferior seam, likely (from regional data) to be very high in
sulphur content, with a variable but typically high ash content. It is also likely to be very
variable in thickness. It does not have sufficient consistency to merit further investigation.
•
The Meltonfield Seam hereabouts is also a variable seam in terms of thickness and
quality. The seam does not have sufficient consistency to merit further investigation.
•
The Dunsil is typically much thinner in most of the provings, and the thicker sections are
unlikely to be sufficiently extensive for mining interest.
•
The Haigh Moor is commonly between 1.20m and 1.50m thick in the borehole data set,
and rarely thickening to >1.50m. Moreover, the seam is only some 15m below the
Swallow Wood, which has been extensively mined; this would prohibit successful
working of the Haigh Moor in many locations.
Overall, it is concluded that there are no resources in any other seams.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 112
Table 4-36
Maltby: Reserves and Resources Comparison
1998
SEAM
PARKGATE
RESERVE (Mt)
Thorncliffe
Totals
TOTAL
I5104C
RESOURCE (Mt)
Mineral Risk Factor Block
Potential
or
Probable Measured Indicated
Tect Sed Panel Zone
(Mt)
Zone
Proven
A
BES
BCN
BCS1
BCS2
BW
1S
BW
1C
BW
1N
BW2
CES1
CES2
CEN
1.9
0.6
-
1.1
-
2.1
1.6
0.7
-
-
3
3
1
1
3
2
3
4
2
2
3
3
B
B
P
P
B
P
0.9
-
-
-
-
1
2
P
-
2.0
-
-
-
2
3
P
-
1.4
3.0
-
3.6
1.2
-
-
3
1
2
2
4
3
3
4
B
P
B
B
CCS1
CCS2
0.7
-
2.6
-
-
-
1
2
1
3
P
B
CCN
-
5.1
-
-
-
2
3
B
CW
4.1
15.2
-
1.2
10.4
-
3
4
Bw
Be
C
-
-
-
2.3
2.7
4.2
9.2
-
2
3
2
5
5
5
4.1
15.2
-
19.6
-
Parkgate Totals
THORNCLIFFE
2002
RESERVE (Mt)
Proven
RESOURCE (Mt)
Mineral Risk Factor Block Change
Potential
or Panel
Probable Measured Indicated
Tect Sed
(Mt)
Reason for Change
A
BES
BCS1
BCS2
BW
1S
-
0.6
-
1.0
-
2.1
1.6
0.7
-
-
3
3
1
3
2
3
4
2
3
3
B
B
P
B
P
No change.
No change.
- 1.9
No change.
No change.
-0.1
-
-
-
-
-
-
-
-
-0.9
Worked.
-
1.0
-
-
-
2
3
P
-1.0
Part worked.
0.4
-
2.2
1.1
0.8
0.4
0.3
-
3.7
1.7
-
-
3
2
2
2
2
3
2
2
4
3
3
3
4
2
2
3
B
P
B
P
B
P
P
P
+0.1
+0.8
+0.5
-1.1
Slight recalculation.
Part worked; part transferred from CEN.
Includes part of old CEN.
Part worked, part transferred to CES.
-0.3
-1.9
Zone downgraded: perceived higher risk.
Part worked, part deleted (thin); includes part of old CCN.
1.0
1.0
3.6
11.4
-
1.2
11.0
-
2
2
3
3
3
4
P
B
B
-0.5
Part transferred to CCS2.
b
BW
1N
BW2
CES1
CES2
CEN1
CEN
CCS1
CCS2
CCS
2i
CCN1
CCN
CW
No change.
B
B
B
Bw
Be
C
-
-
-
2.3
2.7
4.2
9.2
-
2
3
2
5
5
5
B
B
B
No change.
No change.
No change.
1.0
11.4
-
20.2
Worked.
Slight recalculation (T103’ s unit).
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
459000
458000
457000
456000
455000
454000
453000
452000
451000
450000
PAGE 113
449000
399000
448000
447000
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
CW
T10
6
395000
BW
1N
SILVERWOOD
PARKGATE
WORKINGS
CEN
BW
1N
T05
T04
2.48
WORKED OUT
SWALLOW WOOD
2.4
WORKED OUT
PARKGATE
1.5
Sandstone on
or near seam
GD
O
/P
AR
KG
AT
ES
EA
M
A
Faults:
Proven
2.3
Projected
5
Projected from Surface Seismic
10
Fault throws shown in Metres
Agreed Pillars
ick
Th
Phasing Colour Code
2002
am
Se
n
eo
ton T12
s
d
Mu
2003
LE
AS
EA
RE
AB
OU
ND
AR
Y
2004
2005
2006
Sandstone on
or near seam
CES2
T10
PARKGATE
SHAFT PILLAR
SEAM
FACE
PARKGATE
T106R
PARKGATE
T105R
PARKGATE
PARKGATE
PARKGATE
T103R
T06R
T01R
PARKGATE
T22R
PARKGATE
T08R
PARKGATE
T18R
PARKGATE
T20R
T11R
PARKGATE
BES
2002
2003
2004
2005
2006
U.K. COAL MINING LTD
M
SEA
TE DARY
A
G
N
U
RK
/ PA EA BO
GDOSE AR
A
LE
MALTBY COLLIERY
PARKGATE SEAM
RECOVERABLE RESERVES
DATE JULY 2002
0
390000
Figure 4-13
T
Boreholes
GD
LEA O / P
SE ARK
AR GAT
EA
BO E SEA
UN
DA M
RY
2.00
BC
S2
CE
CE N1
CE S1
S1
Thick Mudstone
on Seam
T16
T02
T01
1020
REFERENCE
2.00
T03
393000
Sandstone on
or near seam
SEAM CODE LETTER
2.0
0
BC
S1
of
urse annel
ble co
l ch
Possi al/canne
thin co
CC
S1
2.00
BW
1S
GD
LEA O / P
SE ARK
AR GAT
EA
BO E SEA
UN
DA M
RY
CCS2i
CC
S2
T07
T10
2
I5104C
BARNSLEY
165
Sandstone on
or near seam
T10
1
394000
0
2.0
0
BW2
Section
cms.
SEAM
SURFACE
855
CC
N1
Cannel Coal within
this area.
STRATA SECTION
DEPTH
60
396000
391000
CL
EA
T
795
Sandstone on
or near seam
392000
OF
CCN
G
LE DO
AS / P
E AR
AR K
EA GA
BO TE
UN SE
DA AM
RY
397000
LIN
E
ESS
NTAL STR
398000
IZO
MAX. HOR
GDO
LEA / PAR
SE A KGA
REA TE S
BOU EAM
NDA
RY
500
1000Mtrs
Maltby Colliery: Parkgate Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 114
Maltby Colliery
Thorncliffe Seam
Resource
Not to Scale
Lic
enc
eB
oun
dar
y
Seam Splits
0
1000
2000
Metres
C
Bw
Maltby
Colliery
Be
Seam Splits
Harwoth
Colliery
Figure 4-14
I5104C
Maltby Colliery: Thorncliffe Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.7.3.6
PAGE 115
Geological and Reserve/Resource Conclusions for Maltby
The depletion of the reserves at Maltby equates to the production that has taken place over the
intervening time period of 4.5 years. The mine is currently working the Parkgate Seam in two
areas, one to the west and one to the north east of the shafts and is developing two more faces,
one in each area. Both these areas have different geological problems that, in a seam of
marginal thickness of 1.45m, could put any planned face at risk.
In the western area (BW Zones) the Parkgate rock above comes down onto the seam with the
potential for washout or partial washouts of the seam developing. In the north east area, and
particularly in zone CES the opposite situation exists with a thick mudstone belt being
developed over the faces. This creates weak roof conditions that make mining difficult.
Zones CCS2, CCS2I and CCN1 also are affected by a belt of thin coal some 400m to 500m
wide that caused the T08’ s face to be shortened as the seam was reported to be close to only
1.00m thick in parts.
The only other seam, the Thorncliffe, is present mainly to the east of the shafts. It lies some
12m to 23m below the Parkgate, and is assessed as Indicated Resources by UK Coal plc. At
Maltby, the seam is known only from boreholes. This seam splits to the north west, west and
south west of the shafts, is poorly proved and is only of marginal thickness over most of the
area.
4.7.3.7
IMC Commentary on Reserve/Resources at Maltby Colliery
The following comments summarise IMC’ s interpretations of the recent and present
reserves/resources situation at Maltby.
The Parkgate workings to date have been typically long-run panels that have largely
conformed to the planned layouts. Since entering the seam, only one unit (T14’ s) has stopped
prematurely and only T09’ s, in the thin coal area, has been deleted from the plan. These
observations reflect the generally stable geological setting in the Parkgate, despite the roof
variations, in the areas so far extracted.
Parkgate zones, not entered in the Draft Five Year Plans, constitute the bulk of the remaining
reserve/resource tonnages as quoted by UK Coal plc. These zones are arranged around the
worked area, and some are likely to be left largely unworked, partly because of the way the
mine has developed, and partly because of varying geology within these zones.
The Thorncliffe is unlikely to provide an extensive viable seam that could be worked
following the practical exhaustion of the Parkgate: this follows mainly from consideration of
the seam section, and its expected quality deficiencies. A detailed mapping exercise, perhaps
with new borehole acquisition, would be essential before this seam is ever considered.
The present mining situation will inevitably lead to a significant mark-down in the status of
the reserves and resources as identified by UK Coal plc. Depending on mining strategy, it is
reasonable to suppose that future production will be limited to Reserves in zones BW1N
(T105’ s, T106’ s, part worked), BCS1 (T01’ s), and parts of CCS2/CES1 (T08’ s, T18’ s, and
T20’ s part worked). The remainder of the present reserves and resources will require regrading to Resources/Mineral Potential as appropriate.
The following table summarises UK Coal’ s July 2002 assessment, together with IMC’ s reevaluation of the present and expected mining and marketing situation.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table 4-37
PAGE 116
IMC Reassessment of Maltby Reserve/Resource Summary (01/07/02)
Zone
Category/Mt
(UK Coal,
July 2002 )
Parkgate Seam
A
Resource/2.1
Category/Mt*
(IMC, this study)
Comments
Mineral Potential/2.1
Accessible via drivages south from the shafts. Thin seam
section
BES
Reserve/0.6
Resource/0.7
Resource/1.6
Reserve/0.6
Resource/0.7
Mineral Potential/1.6
BW1S
Reserve/1.0
Resource/1.0
BW1N
Reserve/1.0
Reserve/1.0
BW2
Resource/3.7
Mineral Potential/3.7
CW
Resource/1.2
Mineral Potential/1.2
CCN
Reserve/4.6
Resource/4.6
CCS1
Reserve/0.4
Reserve/0.8
Reserve/1.9
Reserve/0.4
Reserve/0.8
Mineral Potential/1.9
Reserve/2.2
Resource/1.7
Reserve/2.2
Mineral Potential/1.7
Draft Five Year Plans.
Accessible via drivages south from the shafts.
Zone of small faults expected; remainder would
probably be considered too restricted for access.
Draft Five Year Plans: Panel may be abandoned from
the layout if single-face strategy is adopted.
Draft Five Year Plans: Working panel and
developments
This zone is likely to remain unaccessed, particularly if
T103’ s is abandoned. The zone is prone to thick roof
sandstone with potential for washout; there are also old
drivages to negotiate. Fault dispositions make some
areas difficult to lay out.
This is relatively remote from any of the Draft Five
Year Plans, and is expected to include a greater number
of faults, together with an expected major sandstone in
the roof.
Accessible by continuing development of the NE
Laterals.
Draft Five Year Plans.
Draft Five Year Plans: Working unit.
Accessible by continuing development of the NE
Laterals. Intention to do this unlikely
Draft Five Year Plans; T18’ s is a working panel.
Access likely to be lost on the retreat working of T18’ s.
The area may be subject to washouts.
BCS1
BCS2
CCS2
CEN
CES1
CES2
Thorncliffe Seam
Resources/9.2
All zones
Unquantified: insufficient data for detailed layout
appraisals; the seam is likely to have significant ash and
sulphur limitations. Mineral Potential: unquantified (the
Thorncliffe seam is effectively discounted)
*NOTE. UK Coals Parkgate tonnages have been carried forward for the Maltby evaluation, but a complete new
assessment, based on available mining detail, would be expected to show lower totals for most zones.
Table 4-38
Mineral
Potential/unquantified
IMC Reassessment of the Maltby Reserve/Resource Summary (01/12/02)
Million Tonnes
Seam
Parkgate
Thorncliffe
Total
4.7.4
Reserve
Resource
Total
Mineral Potential
5.0
6.3
11.3
12.2
None
None
None
None
5.0
6.3
11.3
12.2
MINE CHARACTERISTICS AND CONSTRAINTS
Production is primarily concentrated in the Parkgate Seam north and north-east of the shafts.
The Thorncliffe seam is available at some 20m below the Parkgate. However, the quality of
this seam is inferior to that in the Parkgate, and it may have difficulty in satisfying some of
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 117
the present market specifications. Its overall thickness of only 1.40m make future options
extremely marginal and limited to a relative discrete area just north of the Maltby shafts.
Outside this area, the seam is affected by splitting.
The Parkgate Seam is at a depth of 900-1000m and like the neighbouring mine Harworth, the
geothermal gradient is quite high. This results in greater ambient temperatures than other
mines in the UK, and can be as high as 400C. To alleviate this to some extent the main
mineral conveyor is installed in the main return as is many of the high powered equipment to
ensure that this heat is moved away from the main working areas.
The Parkgate and other seams are relatively gassy and this can be a constraint on face output.
To minimise these effects methane drainage is practised on all faces.
The Parkgate Seam is on average 1.50m in thickness. Problems with roof control have been
experienced on several faces in and around the areas affected by sandstone channels. When
the sandstones are just above the seam the intervening mudstones have little strength and
result in following dirt, and cavities often forming on the working faceline. The introduction
of two-legged IFS Supports has considerably reduced these problems. Where the sandstones
intrude into the seam itself, difficulties have occurred in cutting the coal. The recent
acquisition of an Eickoff shearer would appear to be better able to cope with such conditions.
Also face delays in face operations due to excessive following dirt has reduced the ROM vend
to 50%. In 2001 the average vend percentage during the year was only in the lower 40’ s %.
When the ROM contains such high proportions of dirt considerable demands are put on the
coal preparation plant with resulting falls in yield. Providing consistent vends of 50% is
maintained, shaft hoisting, coal preparation and spoil tipping should be adequate for any longterm requirements.
4.7.4.1
Roadways and Face Conditions
Roof bolting systems of support are applied both to gate roads and the main laterals. Problems
with the weaker immediate roof have moved the cutting horizon to some 3m to 4m above the
seam. The north laterals have been driven with the roof of the roadway set at this horizon. The
drivage is taken in two lifts, the initial lift leaving a coal floor, second lift involves the cutting
of this coal floor. The completed roadways appear stable but the overall drivage rate is
significantly reduced. Additional rock bolting is required in the roadway ribside at an
extended height of 4m.
Where the sandstone is closer to the roof of the seam, appropriate patterns of bolting and
roadway sections are used. Considerable efforts have been made at the mine to adapt to
changing geology and apply optimum support solutions. Both the officials and the workmen
in the developments showed real awareness of such matters.
The IMC team visited the current working face (T08’ s). Although the seam section appeared
thinner than normal, conditions on the faceline were of an excellent standard throughout.
Unfortunately, the cutting of coal was stopped for a short period due to increased levels of gas
present in the return gate road. Gas constraints on individual faces are evident at Maltby, as is
the need to maximise methane drainage and delivered airflow through the faceline.
At Maltby, a single retreat face working continuously over a 24-hour period is likely to be
constrained by methane emission problems, even with effective control of methane drainage
and airflow. It is IMC’ s opinion that the planned annual outputs would probably require a
production strategy, which includes operating two faces. Also, in IMC’ s opinion the annual
outputs required to make the mine viable are unlikely to be achieved from a single face
strategy given the difficult geological constraints of seam thickness, roof control, and the need
to control methane emissions.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.7.4.2
PAGE 118
Ventilation
The mine is operating in the Parkgate Seam in two areas, north-east and north-west.
Both the north-east and north-west areas have similar booster fans installed to ensure that
sufficient airflow is available to work the production units and provide sufficient ventilation
for development drivage and face salvage.
The airflow available for production faces is on average 45m3/sec, which is sufficient if
methane drainage capture values can be maintained at high levels. Any increase in airflow
above 47m3/sec will give rise to difficulties with dust pick-up in the higher velocities where
the extracted height is limited.
The present production face has occasionally stopped through high methane concentrations in
the return gate. In an effort to improve methane drainage capture efficiencies of the unit;
larger diameter boreholes are being drilled. Some difficulties are being experienced at present
with the conditions on the site where the drilling machine is working.
The ventilation at the return end of the face utilises a ‘Sherwood Curtain’ system of
ventilation. This does not extend back behind the face line more than 5m on observation; and
can give rise to difficulties in controlling both gas fringe and methane drainage.
If the mine chooses to work a single face strategy on three shifts per day, to increase output
then methane constraints will increase, highlighting the need to improve methane drainage
efficiencies.
4.7.4.3
Subsidence
Parkgate Seam
Reserve Zone BW1S:
This area will be mined by T103’ s Panel in the five-year
development plan. This area is crossed by the M18 Motorway and a twin high-pressure gas
main. The panel will affect the village of Ravenfield and the town of Maltby. The mining will
also affect an industrial estate at Hellaby.
Subsidence damage costs for this panel will be high and have been estimated at £1/t.
Reserve Zone BW1N:
T105’ s has been planned to be worked in this area, and T106’ s
is now nearly at an end. Both panels are shown on the five-year development plan
Panel T105’ s will undermine the M18 Motorway and Micklebring village.
Subsidence damage costs are estimated to be around 60 pence/t.
Reserve Zone BCS1:
This area is to be mined by TO1R’ s Panel as shown on the fiveyear development plan. The panel is planned to work along the northern limits of the town of
Maltby. Many houses will be affected. A twin high-pressure gas main plus a gas control
compound will be affected by this panel. Subsidence damage costs will be high having been
estimated at £2.40/t.
Reserve Zone CCS1:
This area will be undermined by TO6’ s Panel as shown in the
five-year development plan. A number of houses will be affected in Stainton, as will an active
quarry.
Subsidence damage costs have been estimated to be around 50 pence/t.
Reserve Zone CCS2:
This area is at presently being worked by TO8’ s. There are few
features of note in this area other than a water main and an operating quarry. The land is
agricultural with some woodland.
Subsidence damage costs are estimated to be around 10 pence/t.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 119
Reserve Zone CES1 and CEN1: The five-year development plan shows panels T18’ s and
T20’ s working in area CES1. T22’ s Panel is planned to work in CEN1 but this is not included
in the five-year development plan.
This area is mainly agricultural with only scattered buildings. The Yorkshire Branch railway
lies in the east and the areas are crossed by a twin high-pressure gas main and water main.
Subsidence damage costs are estimated to be around 30 pence/t.
4.7.4.4
Coal Preparation Facilities
Maltby Colliery has facilities rated at 800t/h, equating to around 80,000t/w or 3.84Mt/a. The
operations include dry fines extraction, large and small coal dense medium systems, spirals,
froth flotation and water clarification. There is a large coal rewash plant included in the
operation. The main product is PSF, a blend of dry fines and cleaned small coal. The larger
fractions are for the domestic market.
4.7.5
4.7.5.1
HISTORIC PERFORMANCE
Production
Table 4-39
4.7.5.2
Historical Production Performance at Maltby
Maltby
1999
2000
2001
Actual Output
million tonnes – saleable
1.262
0.870
1.540
Budgeted Output
million tonnes - saleable
1.500
1.400
1.450
Difference
million tonnes - saleable
-0.238
-0.530
+0.090
Development
Table 4-40
Historical Development Performance at Maltby
Maltby
1999
2000
2001
Actual Developments
metres
3,437
6,095
3,596
Budgeted Developments
metres
7,000
7,000
7,000
Difference
Metres
-3563
-905
-3,404
Production and development in 1999 and 2000 was very badly affected by the adverse
geological conditions encountered in the NW Area. The close proximity of sandstone caused
problems in development progress and the variable and uncertain roof made face conditions,
particularly with regards to T102’ s, very difficult. Development in 2001 was adversely
affected by the seam thinning encountered in T08’ s. This resulted in the gate road drivages
being foreshortened and a change in strategy. It had been intended to pull out of the NW Area
at the earliest opportunity by the up-rating of the infrastructure and establishment of two
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 120
working faces in the NE. The channel of thin coal encountered in T08’ s prevented this from
taking place and resulted in the perpetuation of the NW Area to sustain two-face production.
4.7.6
FUTURE MINING PROJECTION
The mine has operated a two-face retreat strategy in the Parkgate seam. In 1995 and 1996 the
mine produced 1.92Mt and 1.80Mt respectively, however since that time production has been
in decline eventually hitting a low of only 870,000t in 2000. Production in 2001 recovered to
1.54Mt but has declined again to around 1.37Mt in 2002 resulting in further financial losses.
The mine operates two areas, to the North West and to North East of the mine entries. Gas
emissions are high and very high standards of ventilation have to be maintained. A single
face in each area is mined simultaneously, the infrastructures within each individual area at
the present time being unable to support two faces in production.
The main production difficulties have centred on the close proximity of sandstone to the seam
roof. As the sandstone nears the seam, roof control becomes difficult as the intervening strata
falls creating roof cavities. This has been particularly difficult in the NW Area of the mine. It
also causes difficulty with roadway drivage and heavy wear and tear to equipment.
Although the Parkgate Seam has an average seam thickness of less than 1.50m the extracted
height is about 2.00m resulting in very low vends (40%).
The operating costs of the mine are relatively high and are the results of the need to maintain
an extensive infrastructure to support a two face strategy with individual faces located in a
distinct geographical area of the mine.
Following the difficulties experienced in the North West in 2000, it was intended to vacate
this area at the earliest opportunity and replace the output from here with output from the
North East district of the mine. This strategy required the uprating of the North East
infrastructure to enable it to support two faces in simultaneous production. Ideally this
required the advancing of a four-road infrastructure. However the costs of driving and
maintaining four strategic development roads has proved prohibitive and the mine has
reverted to a single face strategy in this area. Also the plans were further constrained by seam
thinning which prematurely curtailed the development of T08’ s. This has not only affected
T08’ s but also the layout of the adjacent panels to the north.
Production in 2002 has also been adversely affected by the seam thinning and sandstone
intrusion on T08’ s. Coupled with the production difficulties, developments have also been
adversely affected. Against this background UK Coal plc put Maltby in review.
Subsequently the mine management and workforce through their union representatives have
put forward a series of alternative plans including plans which seek to maintain two faces and
plans to working a single face. Changes in working practices have also been considered.
On 12th December 2002 UK Coal plc announced the following: “ Unions at Maltby Colliery
have been told that no viable plan has yet been produced for the mine. However, a final
decision on the future of the mine will not be made until early in the New Year pending the
outcome of further talks with the government”. UK Coal plc therefore had at that time no
approved production and development forecasts for the mine.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.7.7
PAGE 121
PRODUCTION AND DEVELOPMENT FORECASTS
4.7.7.1
Two-Face Strategy
Table 4-41
Face
Tonnes
Production Schedule for Two Face Strategy
2003
2004
2005
2006
2007
Development (metres)
6,121
8,793
9,275
8,286
7,930
Total Output (Mt)
1.294
1.516
1.589
1.475
1.680
in Panel
NE Area
T08
765,000
T18
1,164,000
T20
1,205,000
T11
1,272,000
T06
484,000
T22
1,246,000
NW Area
T105
856,000
T103
1,075,000
T01
618,000
The output schedule envisages the continuation of two production faces each working three
machine shifts. Face lengths are generally planned at 290m other than for T105’ s (250m),
T06’ s, which confined by projected faulting is only 200m wide, T01’ s which is 260m and
T22’ s that is 300m wide. The faces are phased at between 10 and 12 shears per day that is
equivalent on the longer faces to around 4,000 tonnes.
Annual production is shown at around 1.5Mt, peaking at 1.68Mt in 2007 with the
establishment of T11’ s (290m) and T22’ s (300m) in the NE Area. Output in 2003 however is
confined to only 1.29Mt, dependent upon the timing of the introduction of T18’ s face, which
is currently being developed. This raises concern regarding the financial outcome during the
immediate period.
Originally it had been planned to work the final three faces in the NW Area in sequence,
T105’ s – T103’ s – T01’ s. This would have resulted in the area being exhausted and vacated
in mid 2006. By this time the infrastructure in the NE Area would have to be up-rated to
enable two faces to be adequately ventilated and serviced to maintain output levels, emphasis
having to be put on strategic drivage.
Due to the current situation regarding replacement roadway drivage it is now not possible to
develop T103’ s in time to replace T105’ s without incurring a protracted gap in production.
This would seriously impact on the output for 2004. The above production schedule therefore
shows the introduction of T06’ s face to maintain continuity following T105’ s thus allowing
sufficient time to develop T103’ s.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 122
T06 is a relatively small panel that is positioned in the NE Area outbye of the current faces
and developments adjacent to T05’ s old panel goaf. The area is at comparatively high
geological risk confined by, and at risk from a band of faulting that runs up its northern flank.
The face is also situated outbye of the booster fans and will be difficult to adequately
ventilate. It is estimated that air quantity on T06’ s face will be restricted to a maximum of
30m3/sec. UK Coal plc specialists are looking at possible solutions to raise quantities to
around 45m3/sec that is necessary to ensure that the planned production levels can be
achieved.
Production in 2004 is therefore at significant risk from the geological uncertainty of T06’ s
and the ventilation difficulties that its working will probably impose.
The development requirement to support the production schedule is shown to be around
8,100m/a, peaking at 9,275m in 2005. IMC has not been presented with the details of the
development programme but it is assumed that the plan includes for sufficient drivage teams
commensurate with such a high requirement, bearing in mind that only three teams are
currently deployed, although five are available. It is noted that colliery manpower increases
from 508 to 551 by 2005. It is also assumed within the programme emphasis is placed upon
the up-rating of the NE Infrastructure to ensure that two faces can be adequately serviced and
ventilated from early 2007 onwards.
This plan is supported by the colliery trade union representatives who are attracted by the
sustaining of manpower levels and the maximisation of extraction of accessible areas of coal.
4.7.7.2
Transition to Single Face Production
Table 4-42
Face
Production Schedule for Transition to Single Face Production
Tonnes
in Panel
2002
2003
2004
2005
2006
Development (metres)
7,895
1,445
5,972
4,610
5,572
Total Output (Mt)
1.366
1.101
1.224
1.300
1.167
NE Area
T08
765,000
T18
1,245,000
T20
1,245,000
T22
1,297,000
NW Area
T106
984,000
T105
856,000
T01
618,000
This plan visualises the completion of the NW Area by late 2005, the last face T01’ s being
worked following T105’ s. T103’ s is therefore not developed. Following completion of T01’ s
the mine is shown to operate a single face in the NE Area. From February 2003 onwards the
plan includes for a reduction in daily machine shifts to four. Initially a single machine shift is
deployed to the NE (T08’ s) and three to the NW (T105’ s). The machine shifts are then
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 123
deployed in a manner to best suit the replacement face programme. Machine shifts further
reduce to three per day with the completion of T01’ s in late 2005.
Production in 2003 is shown as around 1.1Mt rising to 1.3Mt in 2005 before declining back to
around 1.17Mt in 2006 with the establishment of a single face. Whilst two faces are in
operation, performance levels are planned at a maximum of 4 shears per shift, however, this
increases to 4.67 when the mine is confined to a single face. This is equivalent to 14 shears
per day, which produces around 5,700 tonnes. Bearing in mind the gassy nature of the mine
and past experience, it is IMC’ s opinion that methane emissions must be regarded as posing a
risk to the ability to maintain these planned stripping levels.
The development requirement for the period 2003 – 2006 averages around 4,400m/a. In 2003
only 1,445m is planned to be driven utilising two heading teams with a third team being used
for salvage and installation. This reflects the low requirement in the NW Area, T01’ s only
requiring the development of its face heading, its gate roads already being in place and
providing access to the area itself. From 2004 onwards around 5,400m of development is
required per annum. This necessitates the deployment of four drivage teams (three UK Coal
plc + one contractor).
The reduction in face machine shifts and developments results in manpower being reduced
from 530 at present to an average of 388 in 2003. This further reduces to 353 with the
completion of mining in the NW Area and the establishment of single face working in the NE.
4.7.7.3
Cessation of Development
Table 4-43
Face
Production Schedule to the Cessation of Production
Tonnes
in Panel
2003
2004
2005
2006
2007
420
0
0
0
0
1.514
1.371
0.033
0
0
NE Area
T08
765,000
T18
1,175,000
NW Area
T105
856,000
T01
618,000
Development (metres)
Total Output (Mt)
The above production schedule depicts the cessation of all development following the
completion of T18’ s and T01’ s Face heading in the first quarter of 2003. This leaves the mine
in a position to work out T18’ s, T105’ s and T01’ s. The faces are all planned to work three
machine shifts at a maximum of 4 shears per shift. This results in the mine finishing
production in January 2005 and closing. Output in 2003 is shown at around 1.51Mt declining
to 1.37Mt in 2004, output in the last five months of the year being solely from T01’ s. No
manpower figures have been supplied.
UK Coal plc has indicated that from a commercial aspect the programme is potentially
profitable albeit that it will result in the relatively early closure of the mine.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.7.8
PAGE 124
OPPORTUNITIES FOR FURTHER INVESTMENT
Maltby is a consistent and significant loss-maker. In 2001 it generated cash and incurred a
small loss but in 2002, it has lost cash due to stocking and shortfall in output. The mine
benefits from better than average market price but, recently, an Internet auction of industrial
coal from Maltby failed to find a buyer at a starting price of £0.95/GJ. The only positive
aspect is that during 2002, the mine has steadily improved and recent months have been
profitable, although the overall performance for the year is loss making.
Lower profits recently are related to the relatively high rates of development required and also
the shortfall in output. Regardless of this, the mine is budgeted next year to make a loss. In
December 2002 the Company gave a statement that at that time no suitable five-year plan for
future production had been signed. The mine is coming under increasing pressure to submit a
viable plan. Under present circumstances plans for future investment are unlikely to be
considered. IMC concur that the alternative plans so far considered cannot be regarded as
viable.
However, IMC has since learned that in early 2003 a new single face plan has been
formulated, supported by future investment.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.8
ROSSINGTON COLLIERY
4.8.1
BRIEF DESCRIPTION OF SITE
PAGE 125
Rossington is located in Yorkshire, some 5km south east of Doncaster, the colliery lying on
the western periphery of New Rossington village to the south of the M18 motorway. The site
is connected to the railway network.
RJB Mining plc (later to become UK Coal plc) took over Rossington in March 1994 with a
licence under Section 36 (2) (a) of the Coal Industry Nationalisation Act 1946. At the time of
transfer the mine had ceased production and was under ‘care and maintenance’ , the mine
having been previously owned and operated by the British Coal Corporation.
For some years prior to RJB Mining plc taking over, the strategy for the mine had been to
work longwall advance panels to the east of the shafts where the Dunsil seam has combined
with the Barnsley to form a thick coalbed. In 2001, the first conventional longwall retreat face
was established in this area. Note that for most of the Rossington area, the term ‘Barnsley’
includes the underlying Dunsil Seam.
4.8.2
MINE BOUNDARIES, OTHER SURFACE CONSTRAINTS AND ISSUES
The present production area is limited in the east by seam splitting and to the west by old
workings. Additional areas of coal are accessible to the north within an area previously
worked by Markham Main Colliery (Closed in 1996). These coal resources are separated by
the existing licence boundary, which would require extending to facilitate future workings in
this area. Although Rossington is a GDO (General Development Order) Mine, any reliance on
the Markham Main GDO rights remaining in place may prove unfounded. This being the case
planning permission would be required from the Mineral Planning Authority to access and
work these resources.
Access to areas in the south of the present planned face is constrained by the Harworth licence
area. Exploitation of these resources is considered extremely speculative since they are remote
and difficult to access and the area has a high geological risk and would require extensive
exploration.
It is worthy of note that an area to the south of the shafts is available to the mine where the
Dunsil seam has parted from the base of the Barnsley seam. This area was planned for the
first retreat face trials at the mine. The coal in this area is 1.80m thick increasing to the east. If
this coal were to be worked, repairs would need to be made to the present access roadways. It
is worth noting that these faces would not be dependent on the present inbye infrastructure.
4.8.3
GEOLOGICAL ASSESSMENT OF THE MINE
The mine is geologically sited within the concealed East Pennine Basin Coalfield, with
Permo-Triassic strata unconformably overlying the Coal Measures. Rossington works the
combined Barnsley/Dunsil seam at depths varying between 800m and 950m below surface.
This seam that has been worked for decades at the colliery and faces are now 8km from the
shafts. Rossington is bounded to the north by Markham Colliery (closed 1996) and Harworth
Colliery to the south.
RJB Mining took over the mine under section 36 (2) (a) of the Coal Industry Nationalisation
Act 1946. UK Coal plc presently operate the colliery. At the time of transfer to RJB Mining,
the mine had ceased production and was under ‘care and maintenance’ , the mine having been
previously owned and operated by the British Coal Corporation.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 126
Rossington is a GDO mine. Its licence comprises areas of the Barnsley Seam and the
proposed workings are all within the designated seam area and there is no conflict. Any
proposals to access adjacent reserves in the Barnsley Seam of the former Markham Main
Colliery should not rely on GDO rights. It would be prudent to discuss the situation with the
relevant Mineral Planning Authority to establish whether GDO rights are extinguished when
the colliery with which they were associated closes. If this is the case then a planning
application will be required to access and work these reserves.
For some years prior to RJB Mining taking over, the strategy for the mine had been to work
longwall advance panels to the east of the shafts where the Dunsil seam has combined with
the Barnsley to form a thick section coal.
4.8.3.1
Structure
The Barnsley is the only seam worked in the present areas of the mine. Because of this, the
structure over areas of unworked Barnsley has been based on provings from past workings at
Rossington Colliery to the west, Markham Colliery workings to the north and a surface
seismic surveys to the east, north and partially south of the main laterals. Data from
boreholes is also used to help in the structural interpretation.
In general there is a low density of faults above the limits of seismic resolution (10m to 15m
throw). Faults trend south-west to north-east. There is a regional gradient to the north and
north-east of 1 in 15 or lower. The surface seismic data is of reasonable quality.
Based on the area proved by past workings, the intensity of below resolution faulting is
expected to be low. The proving of the anticipated faulting on B100’s tailgate improves
confidence in the revised interpretation of surface seismic. The 4m to 5.5m fault proved in
the east laterals and B102’s main gate, has been picked on surface seismic to the North East.
It is expected to increase in throw to between 12m and 15m. This fault has a significant effect
on the layout to the north of the main laterals and resulted in a major redesign of the proposed
Five Year layout after B102’s.
4.8.3.2
Seams in Reserves
Only one seam, the Barnsley Seam is in the reserve classification for this mine (for the most
part this is a combination of the Barnsley and underlying Dunsil Seams together but referred
to at Rossington as the Barnsley Seam). These reserves are limited to the east by seam
splitting and to the west by old workings. The northern and southern limits are the licence
boundaries with Markham Main and Harworth Collieries respectively.
The Barnsley Seam Characteristics
The immediate roof of the Barnsley Seam consists of relatively weak mudstones and silty
mudstones containing much plant debris. No stronger rocks such as sandstones are seen
within the workings. This weak roof is overlain by firmer siltstones. The weakness of the
roof measures creates difficulties in roof control when rockbolting is used in the drivages for
retreat workings. Present practice is to bolt to a higher horizon of stronger material by the
extraction of this weaker roof.
The seam thickness varies from 2.60m to 3.30m over the areas of the current workings. This
seam thickness is expected to be consistent over the eastern area of the reserves. However
there is an area in the reserves to the south of the shafts, Zone A, where the Dunsil seam is
split away from the Barnsley seam and the thickness in this area varies between 1.80m and
2.20 m. In general the average coal quality of the washed seam is as shown below:
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 127
•
Ash
6%;
•
Sulphur
1.4%;
•
Chlorine 0.6%.
The floor measures of the combined Barnsley/Dunsil seam consist of a thin weak mudstone
seatearth overlying a firmer silty seatearth. Swilleys have also been recorded in the workings
at Rossington in which the seam section is variable. Most present and future planned
workings should be clear of any of the recorded swilleys although Zone En (Ex Markham) in
the north has one such feature. This trends from the last worked face into the centre of the
zone, although its exact course is uncertain.
There are no cover problems at Rossington
4.8.3.3
Reserves/Resources Assessment
The reserve/resource assessment for Rossington was last done in August 2002 and is reported
on by UK Coal plc. The only seam shown in the reserves statement is the Barnsley Seam
which for the majority of the reserve areas is combined with the lower Dunsil seam.
Position with regard to Reserves in 1998
The reserve/resource available at Rossington in 1998 were as summarised in Table 4-44
below based on the knowledge at that time. These have changed up to the last assessment in
2002 in the light of more detailed information and a comparison will be made of the changes
later in Table 4-46 below.
Table 4-44
Rossington Reserve/Resource Summary (01/07/98) (Source: RJB Mining)
Million Tonnes
Seam
Reserve
Resource
Total
Mineral Potential
Barnsley Seam
12.71
3.93
16.64
17.35
Total
12.71
3.93
16.64
17.35
Position with regard to Reserves/Resources in 2002
The majority of the reserves/resources available to Rossington are to the east of the present
workings in zones Ei-v, En and Es. A further zone, zone A, is available to the south of the
shafts in the thinner Barnsley-only section of the seam.
The faces to be worked in the five year period are all in zone E, which contains 8.29Mt of
reserve and has been subdivided by panel layout into zones Ei to Ev.
An area of the closed Markham Main licence area (zone En) is under consideration. The
structure is interpreted from surface seismic, and several large faults are shown, one of which
was proven by Markham Main. The zone is assessed as having 2.07Mt of mineral potential.
A further area to the south east (zone Es) in the Harworth licence area is also being
considered. This contains 4.46Mt of indicated resource.
Finally a residual zone to the south of the shafts, zone A, is still shown as 2.25Mt of measured
resource. This is an area of thinner coal that has workings located on three sides of the zone.
The 2002 assessment is summarised below in Table 4-45.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table 4-45
PAGE 128
Rossington Reserve/Resource Summary (01/07/02)
(Source: UK Coal)
Million Tonnes
Seam
Reserve
Resource
Total
Mineral Potential
Barnsley Seam
8.29
7.475
15.765
2.086
Total
8.29
7.475
15.765
2.086
Changes between Reserve Assessments
Since 1998, there has been a total change in the reserves/resources/mineral potential at
Rossington Colliery of some –16.14Mt. This change in the reserves/resources is due to the
following reasons:
Abandonment of Zones B and C as remnant coal
-3.186Mt
Zone E (1998)/Zones E (i to v) (2002)
Working of part of the Zone
Abandonment of microfaces under Finningley Airfield
Changes in panel layout due to fault proving
-3.657Mt
Zone Es, now based on Block rather than Panel
-4.948Mt
Zone En, different panel layout due to structure projections
-4.389Mt
Total Difference
-16.14Mt
4.8.3.4
Exploration
Depending on the sequencing of faces following B105'
s, a further surface seismic survey will
be required south of the laterals within the next two years. It is expected that a minimum of
one surface borehole is urgently required to the east of the proposed B102'
s face, to provide a
tie in to surface seismic data, together with roof and seam quality information. A second hole
to the south of the laterals should also be considered. UK Coal plc geologists recognise that
these should be programmed within the next two years.
In-seam seismic surveys will be used where appropriate to help delineate the structure, and
monitoring of roof strata variation will need to be continued by means of occasional short
cored boreholes.
4.8.3.5
Other Seams of Interest
There are no other seams of interest at Rossington.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 129
Table 4-46
SEAM
Zone
Barnsley
TOTAL
A
B
C
En
Es
E
1998
RESERVE (Mt)
RESOURCE (Mt) Mineral Risk Factor Block
or
Proven Probable Measured Indicated Potential Tect Sed
Zone
(Mt)
Panel
2.252
1
2
P
A
1.679
3
2
B
1.507
4
2
B
6.435
4
3
P
Eniii
9.404
4
3
P
Es
12.714
4
3
P
Ei
Eii
Eiii
Eiv
Eiv
Ev
12.714
2.252
1.679
17.346
Rossington Reserves and Resources Comparison
2002
RESERVE (Mt)
RESOURCE (Mt) Mineral Risk Factor Block
Proven Probable Measured Indicated Potential Tect Sed or Panel
(Mt)
2.252
1
2
P
2.086
4.456
0.079
1.020
2.228
2.916
0.767
2.047
1.099
7.191
2.252
5.223
4
4
3
3
P
B
1
1
3
3
3
4
1
2
3
3
3
3
P
P
P
P
P
P
Change
Reason for Change
-1.679
-1.507
-4.349
-4.948
-12.714
0.079
1.020
2.228
2.916
0.767
2.047
Deleted from Reserves, no intention to work
Deleted from Reserves, no intention to work, no access
Reduction due to different panel layout and increase structural risk
Now based on Block rather than Panel with increase in deduction
See below Ei to Ev
Now worked out as at November 2002
Panel layout
Panel layout
Panel layout
Panel layout, extension to present layout, possibly lost due to phasing
Panel layout
2.086
Note
1. Panels under Finningley Airfield in zone E excluded in the 2002 Assessment, further reducing the reserve available from the 1998 assessment
I5104C
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
A
sil
un
/D lit
ley Sp
s
rn cm
Ba 30
Figure 4-15
cm
180
cm
200
cm
160
cm
180
200cm - 220cm
463000
I5104C
394000
160cm - 180cm
AL
CO
180cm - 200cm
EL
NN
CA
M
EA
FS
PO
TO
M
RO
FF
OF
TS
LIF
462000
395000
>180cm
459000
>16
0cm
U17&
17A
No 2 Shaft
UC
461000
396000
397000
460000
No 1 Shaft
DC
LOW
20cm
ER
Q
> 2 UART
0C
M T ZITIC
HIC BAN
20cm
K
D
Rossington Colliery: Barnsley Seam Plan
Es
Eiv
Ei Eii
Ev
ce Boundary
Existing Licen
Eniii Eniii
Eiii
Eiii
Proposed Licence Boundary
20
10
B101
398000
399000
Markham Main Colliery
Barnsley Workings
B102
400000
401000
402000
403000
404000
No.2 Shaft
No.1 Shaft
Swil
ley
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
B103
Se
am
464000
B105
S
p
lit
30
cm
466000
B107
To
Ea
st
465000
B106
Lice
n
c
e B
oun
dary
467000
Bo
tto
m
468000
Le
af
of
lit
Sp
am
e
S
Du
n
sil
Sp
lits
469000
st
Ea
To
m
30c
458000
THORNCLIFFE SEAM
Possible
Probable
Proven
BARNSLEY
SEAM
B105R
B103R
B101R
B102R
B100R
0
FACE
Return Ventilation
Intake Ventilation
Possible Pillars
2002
2004
500
DATE JUNE 2002
1000
2005
S.S.S.I.
Agreed Pillars
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
2006
300T
10
5
2.3
B
1018
880
799
813
848
859
751
664
687
702
582
552
461
357
+ 18
Depth
Metres
1000T
120
2
88
1
45
6
95
15
1
C
D
C
D
C
D
C
D
B
920
Site of Arch or Historical Interest
or Ancient Monument
2003
Proposed
Existing
REFERENCE
138
21
14
35
11
48
49
23
15
82
30
91
104
Interval
Metres
Site of Special Scientific Interest
Boundary
Booster Fans
Horizontal Bunkers
Strata Bunkers
Belt Conveyors
Fault throws shown in Metres
Faults:
Seam Section in cms
Boreholes
Depth in Metres
SEAM CODE LETTER
33
148
70
42
239
175
101
137
30
10
BARNSLEY SEAM
DUNSIL SEAM
SWALLOW WOOD SEAM
HAIGH MOOR SEAM
LIDGETT SEAM
KENTS THICK SEAM
NEW HILL SEAM
MELTONFIELD SEAM
TWO FOOT SEAM
25
20
33
SHAFTON SEAM
SHARLSTON LOW SEAM
HOUGHTON THIN SEAM
99
BLYTH SEAM
Section
cms
STRATA SECTION
SURFACE
(ABOVE ORDNANCE DATUM).
STRATA
PAGE 130
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.8.3.6
PAGE 131
Geological and Reserve/Resource Conclusions for Rossington Colliery
It is recognised that the plan for Rossington carries a high geological risk due to it being
based on first seam working in areas of limited structural proving, although the density of
faulting is expected to be low. However the reserve/resource calculations do take into
account this geological risk
There is little doubt regarding seam continuity over the reserve area. Each of the provings is
showing a workable section of similar thickness.
Variation in roof strata over the area of the Five Year plan is a mining risk to the reserves and
will need to be addressed.
The seam is affected by at least one major swilley, the lateral extent of which is not fully
known, and there is a strong possibility of further swilleys over the future reserves, not
detected in the widely spaced provings.
4.8.3.7
IMC Commentary on Reserve/Resources for Rossington Colliery
The present plan carries a fairly high geological risk due to it being based on first seam
working in areas of limited structural proving, although the density of faulting is expected to
be low.
As the Barnsley is the first seam to be worked, all the geological structure has to be
extrapolated and interpreted from existing workings, surface seismic surveys, in-seam seismic
surveys and point data (boreholes).
It is recognised by UK Coal plc that the easterly reserve zones require further surveys to help
determine the structure in better detail and it is also recognised that there is limited geological
data to the south and east of the present planned working area. This lack of data indicates a
high sedimentological and structural risk to the reserves in this area.
The categorisation of the zones in the eastern side of the mine is done, as with the other mines
under UK Coal plc, in accordance with the guidelines.
However, IMC would express some concern at zones Eiii and Ev being categorised at present
as probable reserve. There is as stated above little exploration in the area and upon this basis,
even though there is little doubt as to seam continuity, IMC would re-categorise these zones
as measured resource until the results of any subsequent exploration are available to either
upgrade or discount the zones.
A similar situation exists in zone Es (Ex Harworth) which has been upgraded since 1998 from
mineral potential to indicated resource with the consequential reduction in the tonnages. IMC
again have reservations as to the justification for upgrading this zone. Access to the zone will
be difficult as mining of Zone Eiv and Ev progresses. It is the opinion of IMC that this zone
remains as mineral potential until knowledge of the area changes.
Finally it could be argued that Zone A has most of the geological uncertainty already
determined and could be upgraded from measured resource to probable reserve. The only
reason for categorising this zone as measured resource is the state of the access to the area.
However as no evaluation has been done, as far as can be determined by IMC, as to the
possibility of upgrading this access, it is deemed that this zone is probably categorised
correctly for the present.
All other zones are deemed by IMC to be determined in their correct categories.
Taking into account the comments above and the fact that Zone Ei has now been exhausted,
IMC have re-categorised the zones as follows. The tonnages however for the most part
remain unchanged from the 2002 assessment as these are deemed to be as accurate as possible
for the plans and reserve zones as laid out.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table 4-47
PAGE 132
IMC Summary Reassessment of the Rossington Reserve/Resource
(01/12/02)
Million Tonnes
Seam
Reserve
Resource
Total
Mineral Potential
Barnsley Seam
3.169
7.982
11.15
6.542
Total
3.169
7.982
11.15
6.542
This takes into account the coal worked since July 2002.
4.8.4
MINE CHARACTERISTICS AND CONSTRAINTS
Production is concentrated in the Barnsley Seam lying in an area some 8km to the east of the
two mine shafts at a depth of 900m. Production is from a single retreat face economy
utilising two sets of face equipment and thus maintaining continuity of production.
Rossington was once British Coal’ s lowest cost producing mine. In 2001 a prolonged strike
resulted in considerable loss of planned output.
The bulk of the output at Rossington is sold as PSF but due to recent problems elsewhere
within UK Coal plc, the mine has been able to increase its domestic sales. It would appear that
one of the most favourable characteristics of the Barnsley Seam at Rossington is the high
percentage of large size coal produced in the ROM
Since the production area is now a significant distance from the pit bottom, increasing
reliance is being placed on the services contained within the mine infrastructure. The main
arterial roadways, which have been in place for many years, are predominantly sited within
the ‘goaf’ area of a previously worked ‘breasting’ face. Historically, only limited resources
have been directed towards improving the mine infrastructure. Consequently, the main
locomotive haulage system for men and materials requires extending towards the east with
additional roadway drivage. Extensive repairs are required to enlarge the main intake crosssection to improve the available air quantities for future faces and developments. A
continuing up-rating of the methane drainage system is in progress.
All these requirements will take time and resources to compliment the planned future output
and layouts for the mine. The winding capacity at the shaft is limited to 1.3Mt (saleable) at a
75% vend. UK Coal plc is considering a scheme based on increasing this capacity to 2Mt.
This will require considerable up-rating of the shaft and it’ s winding facilities together with
substantial improvements to underground infrastructure. The company has estimated that such
a scheme would cost in the region of £40M.
More recently, progress has been made towards reaching an optimum design for gate
roadways supported with roof bolts. Previous difficulties have been experienced in trying to
roof bolt these roadways under roof coal. This has resulted in the present idealised parting
used as the roof, some 3m into the mudstone above the seam. Given this horizon, however,
the floor is made up of the bottom section of the seam. Although experience shows that these
roadways are driven in the best direction with respect to stress, they are constrained by the
above problems. Drivage rates are only moderate due to the high density of bolts used in the
roof and sides of the gate roadway. Coal floors tend to lift particularly in areas of high stress,
such as abutment zones immediately in front of the retreating face lines. The 3m of mudstone
is cut and graded out over several extended supports from the main end of the face. Delays
can occur when working this area.
The latest face installation has recently been completed. This has taken longer than expected
due to difficulties in driving the face heading. These drivages are both wider than the gate
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 133
roadways and located in the worst direction for horizontal stress. Whilst driving the last face
heading a severe ‘weighting’ was experienced in one area with a partial detachment of the
immediate roof, requiring extensive repairs.
Gate roadways for future faces have been laid out in the most favourable direction with
respect to the horizontal stress. Unfortunately, this direction is not the same as the main
direction of faulting in the present production area. This will effectively sterilise the next
longwall panels north of the east laterals. The production plan has now been changed to firstly
work the next longwall faces to the south of the east laterals.
Accepting that mining conditions are not easy at Rossington, the Barnsley Seam is favourably
thick with resulting vends of 75% being common. In general longwall faces have been very
successfully worked.
4.8.4.1
Ventilation
The workings in the Barnsley Seam will be an average of 10km from the shafts. The
ventilation into the main working area is provided by a combination of main mine fan and an
inbye underground Booster Fan installed within East 2nd Return. The restriction to increased
airflows within this part of the mine is due to the cross-sections of the East Intake conveyor
roadway, which requires enlargement of the roadway to improve the quantities of air to the
inbye working areas of the mine.
The area in the main return, which is being by-passed, is planned to be completed by January
2003. Although this will reduce the pressure loss within this area by 900Pa, this will be redistributed along the intake conveyor road due to slight increase in airflow, with an additional
pressure loss of 700Pa. Therefore, without the repairs to the intake conveyor road the
proposed increase in duty of the Booster Fan will not be realised.
The Barnsley Seam is prone to spontaneous combustion and a number of incidents have
occurred at this and other mines within the area. A recent incident on 68’ s loco road in the
region of 90’ s face, has now been resolved.
4.8.4.2
Subsidence
Reserve Zone Eii: Mining has recently ended in Block Ei (Panel B100’ s) and is beginning
in panel B102’ s. This panel will affect parts of the villages of Blaxton and Finningley. The
land is relatively low lying and a major drain will be undermined. In addition, a 0.5m
diameter water main will be affected.
Costs for mining subsidence damage and damage preventative works have been estimated to
be around 60 pence/t
Reserve Zone Eiii: Plans exist for the mining in this area but they are not within the Fiveyear development plan. Blaxton village is in this area. The area is mainly low lying,
agricultural land. A drainage pumping station is likely to be affected and damage remedial
works are likely to be costly
Surface damage costs for this are estimated at 50 pence/t.
Reserve Zone Eniii: Plans also exist for the mining in this area but they are not within the
Five-year development plan. The River Torne crosses the north-west part of this area and may
be affected if mining proceeds as planned. This area is flat and low lying with major drains. In
addition, a twin 600mm high-pressure gas main would be affected.
Subsidence damage costs are estimated to be 50 pence/t.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 134
Reserve Zone Eiv: This area includes Panels B101’ s, B103’ s and B105’ s, which are in the
Five-Year development plan.
The panels in the Five-year development plan are under mainly low lying, agricultural land
traversed by major drains. Finningley village will be affected as will the DoncasterGainsborough railway.
Costs in this part of the area have been estimated at 90 pence/t.
The western part of Eiv would affect Finningley airfield and village. IMC understands that
there is an application presently with the secretary of state to upgrade the former RAF facility
to a cargo and passenger airport. A potato processing plant could also be affected by mining
in this area.
As matters presently stand with Finningley Airfield, subsidence damage costs will be in the
order of £1/t. However, should the upgrading proposals go ahead, subsidence damage costs
would almost certainly preclude any extensive mining in this area.
Reserve Zone Ev:
Panels B107’ s, B109’ s and B111’ s have been planned although they
are not included in the Five-year development plan.
This area is mainly agricultural land, low lying and crossed with major drains. The area is also
crossed by the Doncaster to Gainsborough railway
Subsidence damage costs have been estimated to be some 40 pence/t.
Reserve Zone Es:
Finningley airfield lies across the western part of this area; there is also
a major drain with associated pumping station in the east half of the area. Everywhere the
predominantly agricultural land is low lying and drainage problems will be inevitable.
Subsidence damage costs for the east half of the area are estimated to average some 30
pence/t. The west half the costs will be some £1/t unless the airfield is upgraded in which case
subsidence costs will be prohibitive.
Reserve Zone A:
Area ‘A’ lies some 7km to 8km to the south-west of other reserve areas
at this colliery. A mining layout has been planned but the panels are not included in the fiveyear layout.
The River Torne and a main drain cross this low lying, agricultural land.
Subsidence damage costs have been estimated to be around 30 pence/t.
4.8.4.3
Coal Preparation Facilities
Built in the mid 90’ s the plant consists of a natural medium barrel washer together with
primary and secondary natural medium cyclones, a rewash facility for domestic fuel, fines
treatment and water clarification. The plant is rated at 400t/h, depending on feed conditions. If
the need arises, the potential plant capacity is around 40,000t/w equating to 1.92Mt/a.
The ROM from the shaft is stockpiled and recovered at 400t/h to feed the plant via a rotary
breaker reducing the top size to 150mm and then being fed to a dry fines extraction screen.
This is the dry constituent of the PSF.
Oversize from the screen, nominally 12mm – 0, is fed to the barrel plant, the resulting discard
is dewatered before going for disposal, the washed product from the barrel is dewatered and
classified. The plus12mm goes to a two product Dense Medium Drum, yielding clean coal for
the domestic market and a middlings, which is crushed and added to the PSF. The underflow
from the classifying screen containing 12mm – 0 solids, is pumped to primary natural
medium cyclones, the clean coal is the low ash constituent of the PSF. The discard from the
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 135
primary separation is pumped to a secondary system recovering middlings that is added to the
PSF. The discard is dewatered and added to the coarse dirt for disposal.
Underflow from the Cyclone plant drainage form the natural medium for the process, to
control this a portion is treated in slurry cyclones preceding a small bank of spiral separators.
The recovered product from the spirals, having been dewatered is added to the PSF blend. The
Slurry cyclone overflows, together with the spiral discard is fed to a clarifier. The decanted
liquid is reused in the process, and the underflow is pumped to a filter for dewatering prior to
disposal on the tip.
ROM production at Rossington is around 30 to 40,000t/w with an average vend of 75%, 60%
of the product is PSF, the remaining 40% is domestic fuel.
ROM stocks at the mine were minimal, less than 8,000 tonnes, however there was around
110,000 tonnes of domestic fuel on stock, which, when recovered, would be reduced to
55,000 tonnes of saleable domestic fuel. Due to breakage, the balance would then form part
of the PSF blend.
4.8.5
4.8.5.1
HISTORIC PERFORMANCE
Production
Table 4-48
4.8.5.2
Historical Production Performance at Rossington
Rossington
1999
2000
2001
Actual Output
million tonnes – saleable
0.901
0.684
0.444
Budgeted Output
million tonnes - saleable
0.940
0.900
1.039
Difference
million tonnes - saleable
-0.039
-0.216
-0.595
Development
Table 4-49
Historical Development Performance at Rossington
Rossington
1999
2000
2001
Actual Developments
metres
2,928
1,318
1,633
Budgeted Developments
metres
3,822
3,481
3,801
Difference
Metres
-894
-2163
-2168
Production and development in 2000 and 2001 was adversely affected by industrial relation
problems that centred on difficulties in agreeing performance bonus levels particularly with
respect to the introduction of retreat mining. This resulted in at first a ‘work to rule’ by the
workforce and a corresponding delay in the procurement of face equipment for the first retreat
face. Matters finally reached a head in 2001 with the workforce going on all-out strike.
Issues have been resolved and the mine resumed operations at the beginning of 2002.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.8.6
PAGE 136
FUTURE MINING PROJECTION
The strategy for the mine is a continuation of a single retreat face in the Barnsley Seam
operating some 8km to the east of the mine entries utilising two sets of face equipment to
ensure continuity of production. Production is expected to be maintained at around 1.2Mt/a.
4.8.7
PRODUCTION AND DEVELOPMENT FORECASTS
4.8.7.1
Production
The Draft Five Year Production Schedule is as follows:
Table 4-50
Face
Tonnes
in Panel
Draft Five Year Production Schedule
2002
2003
2004
2005
2006
Barnsley
B100R
B102R
1,098,000
B101R
1,091,000
B103R
1,600,000
B105R
1,600,000
Development (metres)
1,984
4,874
5,000
5,000
5,000
Total Output (Mt)
0.824
1.170
1.200
1.200
1.200
As outlined above a strike that temporarily caused the cessation of mining activities during
the second half of 2001. Whilst the mine was closed the working areas were temporarily
sealed. In re-establishing the mine following the dispute, B100R’ s face was re-opened and recommenced production in advance of the developments. This caused a disparity between face
production and replacement development that resulted in a gap in face production from
August to December 2002 as B102R’ s development and installation was completed. This has
resulted in output for 2002 being limited to around 0.82Mt.
Production from B100R, the first retreat face in the area, was very encouraging, with around
53,000t produced in its best week. This has given confidence to the planned rate of 10 shears
per day, which is equivalent to 29,100t/w.
The faces have been standardised at 276m wide with an extracted height of 2.55m, leaving
coal tops to maintain a good working roof. B102R has a face run of 1,207m and having
recently commenced production is planned to operate for around 10 months reaching
exhaustion in October 2003. Its replacement face, B101R, has a planned run of 1,200m. This
is dictated by the need to try to avoid a production gap and is based on the gate road
developments achieving 65m/w. The face heading will be undertaken at the appropriate time
to ensure that the face is got ready by November 2003, a small production gap already being
shown.
It is anticipated that the disparity between face production and developments will be
overcome with the blocking out of B103R, which is planned to have a face run of around
1,800m. The establishment of such long life units will enable the mine to operate at its
current shaft capacity of around 1.25Mt/a of saleable output based on a 75% vend.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 137
It must be noted, that as the mine is operating at a depth of around 900m substantial pillars
150m wide are being left between the faces. This coupled with the coal being left at the inbye
end of the face runs due to lack of development time results in a low percentage extraction of
the available reserves.
4.8.7.2
Development
Three development teams are currently deployed, two UK Coal plc teams driving B101R’ s
and a team of contractors driving the two main lateral roadways forward to the position of
B103R’ s gate roadways. The main roadways are being driven utilising steel arches and are
phased at 30m/w. The gate roads use roof bolts as the primary means of support and are
phased at 65m/w. At the present time the headings are ventilated in series with the face.
There is only some 45m3/sec available to the present production area and is a constraint on the
number of developments.
In addition to the three development teams there is a team of contractors carrying out essential
roadway repairs, enlarging the main return just inbye of the main booster fans. This work
includes the short drivage of a roadway to eliminate an area of the return that is in very bad
condition. UK Coal plc anticipates that when these repairs are completed early in 2003 that
air quantities should increase to around 70m3/sec. It is IMC’ s opinion that this may be
difficult to achieve without carrying out a total of around 700m of roadway enlargement that
is also required within the Main Intake conveyor road.
The development required to sustain face production at 1.2Mt/a is around 5,000m/a. The
development schedule shows the introduction of a fourth heading team in March 2003 to
drive the Intake Lateral forward. Four teams are then maintained, two developing the laterals
and gate road stubs and two driving the gate roads and face headings.
4.8.7.3
Risk
The main roadway infrastructure from the pit bottom area to the working area has been in
place for many years, and confined within the goaf area of an old advance face, is in need of
repair and upgrade. Mining activity is currently constrained particularly with regards to man /
material transport and ventilation.
It may prove difficult to provide sufficient quantities of air to establish four development
drivages whilst maintaining a face in full production. Given the constraints, the face
replacement development programme is demanding with gate roads planned at 65m/w. Any
shortfalls in drivage performance will potentially result in face gaps or the foreshortening of
face runs.
4.8.7.4
Longer Term Plans
Currently UK Coal plc has no firm plans other than for the perpetuation of the present
strategy to mine the existing area at around 1.2Mt/a. There are further areas towards
Markham in the north and Harworth to the south, but these are remote and would require
major strategic drivages. It is unlikely that the current infrastructure in its present form could
support such development.
UK Coal plc has alluded to potentially increasing output to around 2.0Mt/a. This would
include substantial repairs to the existing infrastructure and the upgrading of the locomotive
system to high speed. It also includes for the installation of new headgear and skip plant.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.8.8
PAGE 138
OPPORTUNITIES FOR FURTHER INVESTMENT
Currently profitable, this mine is also cash positive despite an increase in stocks through
2002. The mine infrastructure is extensive and in the most part confined with roadways in
seam from a previously worked ‘breasting’ face to the east. Constraints both on ventilation
and manriding access are clearly evident in the present operations. Improvements are
required both to sustain present planned maximum outputs of 1.2Mt/a and for possible longterm prospects to raising output to 2.0Mt/a. The mine has estimated that to increase output to
this level will require some £40M investment.
It is thought unlikely in its present situation that the mine would be able to accommodate such
high levels of investment and more importantly achieve a satisfactory level of return. This
reticence is based upon the levels of mining and geological risk associated with the plan. UK
Coal plc have recognised some of the constraints and is planning further surface exploration
in the east to hopefully reduce some of the risk through obtaining favourable information.
The most likely scheme to be considered for Rossington is one based on firstly sustaining the
current output and then raising the level to 1.2Mt/a.
It is IMC’ s view that significant investment is needed to up-rate the existing infrastructure to
support the present planned output level of 1.2Mt/a. Some 700m of Intake Roadway require
enlargement to improve the ventilation to levels commensurate with planned development and
production. The locomotive transport system also requires to be extended and improved. The
existing reserve base could possibly support such investment with the assistance of aid.
However, an exploration programme would also be of benefit in first minimising geological
risk and proving the extent of the reserve within the current working area. Assuming that a
viable scheme could be prepared then the extension of the main infrastructure roadways could
also be considered as a potential investment scheme.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.9
THORESBY COLLIERY
4.9.1
BRIEF DESCRIPTION OF SITE
PAGE 139
Thoresby is located in the Nottinghamshire countryside some 12km north-east of Mansfield
between the villages of Edwinstowe and Ollerton on the A6075. The mine site is connected
to the rail network.
Thoresby Colliery was established between 1925 and 1928, since when production has been
from the High Hazles, Top Hard and the Parkgate seams. The mine entries consist of two
6.4m diameter shafts, No.1 and No.2, which are 691m and 688m deep respectively.
The main colliery site covers an area of around 31 hectares. There is an additional area of 154
hectares mainly for tipping. The mine surface has comprehensive facilities including a coal
preparation plant and coal stocking areas.
The Deep Soft Seam was accessed in 1988 from the Parkgate Seam but was not developed for
Longwall production. Production from the Parkgate seam commenced in 1977 and is
ongoing. RJB Mining (later to become UK Coal plc) took over Thoresby in January 1995,
following privatisation, at which time it was in full production.
The current mining operation consists of a single retreat face with supporting developments
producing around 1.7Mt/a.
4.9.2
MINE BOUNDARIES, OTHER SURFACE CONSTRAINTS AND ISSUES
The Licence Boundary at present delimits an area of Parkgate Seam, together with zones of
High Hazels and Deep Soft seams. Reserves in the Parkgate that previously belonged to the
former Ollerton Colliery have also been included. Mine boundaries are formed by adjacent
collieries either working or abandoned to the north-west and south, and by geological
constraints to the east.
Thoresby is now working the last face (190’ s) in the west, and having accessed the Ollerton
workings is developing the first face in this area (42’ s).
4.9.3
GEOLOGICAL ASSESSMENT OF THE MINE
Thoresby Colliery is situated in the Nottinghamshire part of the East Pennines Coal Basin.
The mining area is bounded by the active Welbeck mine to the northwest, and closed mines to
the north and south. The eastern limit is controlled by seam splitting. The Coal Measures are
overlain by Permo-Triassic strata containing aquifers, but there is sufficient cover to remove
any risk of water ingress.
4.9.3.1
Structure
In general the seam dip is to the southwest in the current and proposed Parkgate workings as
it is influenced by the Bothamsall anticline to the north. There are no major faults in the
working area, but the Farleys Wood/Bothamsall Fault forms the northeast boundary of the
working area. Minor faulting is seen at the mine but has proved little hindrance to the
extraction of the present seam and most of this minor faulting is known from overworking in
the Top Hard Seam.
4.9.3.2
Seams in Reserves
The following seams are considered to be in the reserve classification for this mine. These
are shown below: -
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
•
The Parkgate Seam
•
The Deep Soft Seam
•
The High Hazles Seam
PAGE 140
Parkgate Seam Characteristics
In the 190’ s area of the old Manton reserves to the north west, the roof is expected to be a
siltstone with possible channel sandstone belts. Towards the outbye end of the panel, a roof
coal converges and weaker immediate roof may be present.
In the Ollerton reserve zone to the east, 42’ s to 45’ s panels will be affected by a wide channel
sandstone which locally erodes the seam. The sandstone will be present over a progressively
longer distance as the panel sequence advances eastwards, and on the shortened 45'
s panel, it
will be in close proximity for the majority of the face life. In the southern part (55’ s and 56’ s)
the roof should be mudstone and siltstone.
The Parkgate Seam section generally contains a thin dirt, but this thickens in the southeast in
Zone Esii. Seam thickness in general is between 1.55m to 2.10m including dirt with the coal
thickness varying between 1.50m to 1.85m.
In more detail, on 190'
s panel in the old Manton Area, the Parkgate Seam ranges from 2.10m
to 1.75m, with 0.05m to 0.10m of dirt in two thin bands. However, the section in the north
Ollerton reserve zones ranges from 2.00m to 1.55m, reducing towards the north. The coal
section in this area contains little if any in-seam dirt.
The seam quality is generally better than the Deep Soft Seam shown above with generally less
clean coal ash and sulphur, although the sulphur is relatively high. The general quality of the
seam is shown as:
As mined ash 6-31%
Coal ash
5-8%
Sulphur
1.8-2.3%
Chlorine
0.6-0.7%
The immediate 0.25m of floor is usually a weak seatearth with strong siltstone/sandstone
below. Towards the east the thickness of “ weak” floor generally increases. Sections of
0.20m to 0.30m are likely on the easterly panels with even thicker weak floor, in excess of
0.30m, expected on the most easterly panel.
The Deep Soft Seam Characteristics
The information on the roof of this seam is limited, but channel sandstone belts are expected
to cross the area on a southwest-northeast trend, and the normal mudstones and siltstones
would be replaced by stronger and possibly erosive sandstones and sandy siltstones.
The seam itself contains one or two dirt partings, and varies from 1.30m to 2.15m including
dirt, with coal thickness 1.26m to 1.70m. A split between the Roof Soft and Deep Soft is
expected to cross the area of the reserves in this seam with the majority of the panels laid out
in zone Ds and Fs showing between 0.30m and 0.60m of dirt occurring as this split becomes
larger. The 0.60m split line is shown as the boundary of the reserve zones in the south. The
quality of the seam is generally expected to be as shown below. Of particular note is the high
sulphur content of the seam.
As mined ash 16-35%
Coal ash
I5104C
7-9%
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 141
Sulphur
2.3-3.2%
Chlorine
0.6-0.7%
The floor measures to the seam are generally a weak mudstone seatearth across the area.
The High Hazles Seam Characteristics
The roof of the High Hazles is generally mudstone or silty mudstone. However, a channel
sandstone belt proved in the Mansfield workings to the south west, may cross the area of the
resources indicated in this seam. The coal is generally of a good quality with no dirt partings
but has a very thin seam section of only 1.07m to 1.15m thick. The general quality of the
seam is:
Coal ash
5-6%
Sulphur
1.2-1.4%
Chlorine
0.7%
The floor measures are usually mudstone or silty mudstone seatearth but a swilley with
associated hard floor areas is expected to cross the area.
4.9.3.3
Reserves/Resources Assessment
Three seams, as stated above, are shown in the 2002 reserve assessment for the colliery.
These have changed from the previous review and these changes are detailed below.
Position with regard to Reserves in 1998
The reserves/resource available at Thoresby in 1998 were as summarised in Table 4-51 below
based on the knowledge at that time. These have changed up to the last assessment in 2002 in
the light of more detailed information and a comparison will be made of the changes later in
the report.
Table 4-51
Thoresby Reserve/Resource Summary (01/07/98) (Source: RJB Mining)
Million Tonnes
Seam
Reserve
Resource
Total
High Hazles
8.092
8.092
Deep Soft
8.717
8.717
Mineral Potential
Parkgate
12.227
3.393
15.620
1.033
Total
12.227
20.202
32.429
1.033
Position with regard to Reserves/Resources in 2002
Only the Parkgate Seam has been worked since 1998, but the Deep Soft reserves have also
been reduced as some have been transferred to Welbeck. The current reserve assessment is
summarised below in Table 4-52
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table 4-52
PAGE 142
Thoresby Reserve/Resource Summary (July 2002)
(Source: UK Coal)
Million Tonnes
Seam
Reserve
Resource
Total
High Hazles
8.092
8.092
Deep Soft
7.272
7.272
Mineral Potential
Parkgate
6.398
4.217
10.615
1.033
Total
6.398
19.581
25.979
1.033
Changes Between Reserve Assessments
Parkgate Seam
The reserves at Thoresby are all in the Parkgate Seam. These have reduced from 12.227Mt to
6.398Mt since 1998. The reasoning for this reduction is as indicated below.
Zones worked
-4.460Mt
Layout/Zone area changes
-1.369Mt
Total
-5.829Mt
Resource Zones
High Hazles
This is unchanged at 8.092Mt of Indicated Resource. However this seam is thin and should
be removed from Indicated Resources to Mineral Potential as there is no intention to access or
work it.
Deep Soft
The total Indicated Resources in the Deep Soft Seam have been reduced by 1.422Mt from
8.717Mt to 7.727Mt. This is accounted for by the transfer to Welbeck of part of Zone Fni.
Parkgate
The Indicated Resources have been increased by 0.824Mt from 3.393Mt to 4.217Mt due to
changes in zone areas in the east. There is also an unchanged zone of Mineral Potential
(Esiii) containing 1.033Mt. This is in the Kirton Brickworks pillar which could become
available if the works were to close.
4.9.3.4
Exploration
The southeast reserves in Es are restricted by a seam split which is poorly proved, and the
need for a surface borehole has been noted by UK Coal plc. This would be to the east of the
existing borehole in 56’ s proposed panel, to investigate the workability of 57’ s. Underground
exploration would include in-seam seismic surveys to check on the faulting to the north of
44’ s proposed panel, and detailed surveys to investigate the possible washouts on 43’ s, 44’ s
and 45’ s panels.
4.9.3.5
Other Seams of Interest
There are no other seams of interest at Thoresby
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 143
Table 4-53
SEAM
Zone
High Hazles
Deep Soft
Parkgate
Gt
Gn
Gs
Ht
Hb
C
Dn
Ds
Fni
Fsi
C
Cni
Cnii
Dn
Dni
Eni
Enii
Eniii
Esi
Esii
1998
RESERVE (Mt)
RESOURCE (Mt) Mineral Risk Factor Block
or
Proven Probable Measured Indicated Potential Tect Sed
Zone
(Mt)
Panel
3.495
3
3
P
Gt
1.290
3
3
P
Gn
1.309
3
3
P
Gs
1.131
3
3
P
Ht
0.867
3
3
p
Hb
0.378
2
4
P
C
3.367
2
3
P
Dn
2.132
2
4
P
Ds
2.063
2
4
P
Fni
0.777
2
4
P
Fsi
1.289
2
3
P
1.272
3
4
P
Cni
1.421
3
3
P
0.673
1
1
P
1.077
1
2
P
1.184
3
3
P
Eni
3.808
3
3
P
Enii
1.825
4
3
b
Eniii
Eniv
Env
Env
1.503
2
3
P
Esi
1.568
3
4
B
Esii
Esii
Esiii
TOTAL
I5104C
1.033
1.750
10.477
20.202
1.033
3
2
B
Thoresby Reserves and Resources Comparison
2002
RESERVE (Mt)
RESOURCE (Mt) Mineral Risk Factor Block Change
Proven Probable Measured Indicated Potential Tect Sed or Panel
(Mt)
3.495
3
3
P
No change
1.290
3
3
P
No change
1.309
3
3
P
No change
1.131
3
3
P
No change
0.867
3
3
p
No change
0.382
2
4
P
No change
3.350
2
3
P
No change
2.132
2
4
P
No change
0.641
2
4
P
-1.422
0.777
2
4
p
No change
-1.289
1.325
2
2
P
+0.053
-1.421
-0.673
-1.077
0.630
3
3
P
-0.554
0.625
2
3
P
-3.183
1.632
3
3
P
-0.193
0.574
3
4
P
+0.574
0.438
4
3
P
+0.438
2.078
4
3
B
+2.078
1.612
3
3
P
+0.109
0.571
3
5
P
-0.997
1.130
3
4
B
+1.130
Esiii
1.033
1.325
5.073
19.581
3
2
b
No change
Reason for Change
Transferred to Welbeck
Worked
Layout change. 190’ s Currently working
Worked
Worked
Worked
Reduced area
Reduced area
Changed zone
New zone was part of Eniii
Was part of Eni
Includes old zone Eniii
Layout change
Part of old Esii
Increased area
Brickworks pillar
1.033
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 144
REFERENCE
SEAM CODE LETTER
MANTON
PARKGATE WORKINGS
PG
Boreholes
Faults:
Proven in Parkgate Seam
Projected
375000
375000
SHAFT SECTION
Projected from Surface Seismic
10
Fault throws shown in Metres
Section
cm
STRATA
Parkgate Seam shown in black
Interval
Metres
Depth
Metres
DRIFT
U
U
BO
UN
DA
RY
i
Cn
U
Split 20cm
AR
EA
CO
LL
IE
RY
Phasing Colour Code
BEVERCOTES
PARKGATE WORKINGS
60
MIDDLE PERMIAN MARL & SAND
2002
191
2003
2004
374000
2005
2006
LOWER MAGNESIAN LIMESTONE
51
LOWER PERMIAN MARL
BASAL PERMIAN BRECCIA
5
1
BOTHAMSALL OILFIELD
U
U
U
480
481
1
HIGH HAZLES SEAM
Split 20
cm
U
57
LOCO ROAD HORIZON
53
U
No. 2 SHAFT BOTTOM
No. 1 SHAFT BOTTOM
Parkgate
Face
U
U
372000
WELBECK
PARKGATE WORKINGS
372000
BRAIDED SANDSTONE
CHANNELS IN UPPER ROOF
LOCALLY EROSIVE INTO
DRIVAGE
U
U
2002
2003
2004
2005
688
691
14
2006
DEEP SOFT SEAM
705
35
192 R
190 R
42 R
43 R
44 R
45 R
55 R
56 R
U
U
635
U
U
U
538
540
2
95
373000
BRAIDED SANDSTONE
CHANNELS IN UPPER ROOF
LOCALLY EROSIVE INTO
DRIVAGE
?
242
247
248
232
TOP HARD SEAM
U
129
131
2
UPPER MAGNESIAN LIMESTONE
U
373000
129
BUNTER SANDSTONE
S.S.S.I.
0 .31
Roof Co
al
U
Roof Coal
W
EL
BE
CK
374000
Site of Special Scientific Interest
LIC
EN
CE
BRAIDED SANDSTONE
CHANNELS IN UPPER ROOF
LOCALLY EROSIVE INTO
DRIVAGE
Edged
Green
Agreed Pillars
U
PARKGATE SEAM
740
UK COAL MINING Ltd.
THORESBY COLLIERY
PARKGATE SEAM
RECOVERABLE RESERVES
REFERENCE:- SP/PG/250/19
DATE JULY 2002
SCALE : 1/10,000
0
500
1000m
T SEA
ROA
DWA
Y IN
DEE
P SOF
s
m
0c
Presumed
Waterlogged
Area
WATERLOGGED
AREA
42
OLLERTON PARKGATE
WORKINGS
U
U
En(ii)
U
U
U
U
TH
EM
IN
E
VE RTICA L
BU NKER
500T
IN CLI NED
BUN KER
1000T
45
ck
Thi
DEC 2005
370000
En (v)
369000
Sandstone Beds
within 2m of the Seam
U
U
0.2
in
1 00
1
in
15
1
1 in 70
No1
SHA FT
1 in 4
1in
B AT TE R Y L OC O
C H AR GI N G ST N
No 1
S H A FT
THORESBY
COLLIERY
U
No 2
SH A F T
1 in 70
7 .6
152 mm PI P E
TO BA L AN C E
ST OPP I N G
No2
SH AFT
HAZLE
B UNKE R
850T
Es(iii)
U
368000
1 .6
1 in 3
1 in 5.3
1
1 in
2
0
U
32
Lev
el
367000
OLD OLLERTON COLLIERY
PIT BOTTOM AT TOP HARD LEVEL
V ER T IC A L B U N KE R
33
34
35
DEC 2006
EY
U
SW I LL
U
FEB 2006
BILSTHORPE
PARKGATE WORKINGS
U
57
56
55
U
SE A LE D
199 2
STA P LE
PIT "A "
NOV 2006
30cm Split In Parkg
ate Seam
U
n33
vel
1
VERTIC AL
BU NKER
1000T
1i
Le
in
18
U
Es(ii)
368000
Es(i)
FO
R
44
SWILLEY
U
U
43
Es(i)
BO
UN
DA
RY
TH
ICK
ER
ON OSIV
PA E S
RK AN
GA DS
TE TO
NE
LIC
EN
CE
369000
AR
EA
m
Sea
on
e
n
to
nds
Sa
ve
i
s
Ero
S W I L L EY
U
En(iv)
370000
U
En(iii)
En(iii)
60
cm
s
Sandstone Beds
within 2m of the Seam
M
t3
Dir
Dir
t
U
Waterlogged
Area
371000
m
Sea
gate
Park
m
ea
-s
l In
ta
To
To
tal
Inse
am
En(v)
U
En(i)
371000
In
plit
mS
30c
En(i)
U
367000
U
U
U
B A TT E RY LOC O
C H A R GIN G S TN
366000
366000
Es (ii)
365000
365000
472000
471000
470000
469000
468000
467000
466000
I5104C
465000
464000
463000
462000
461000
460000
Figure 4-16
364000
Thoresby Colliery: Parkgate Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 145
REFERENCE
SEAM CODE LETTER
DS
Boreholes
Faults: Proven in Parkgate Seam
5
Projected
SHAFT SECTION
Projected from Surface Seismic
Section
cm
STRATA
Fault throws shown in Metres
Interval
Metres
Depth
Metres
DRIFT
Parkgate Seam shown in black
375000
Deep Soft Seam shown in red
BUNTER SANDSTONE
129
DEEP SOFT FLOOR
COAL SPLIT
DEEP SOFT LOWER LEAF
THINS & DETERIORATES
UPPER MAGNESIAN
LIMESTONE
MIDDLE PERMIAN
MARL & SAND
DEEP SOFT / ROOF SOFT SPLIT
LOWER MAGNESIAN
LIMESTONE
LOWER PERMIAN MARL
BASAL PERMIAN BRECCIA
191
51
242
247
248
5
1
DEEP SOFT LICENSE AREA
374000
129
131
2
60
232
DEEP SOFT WORKINGS
.
AF S
LE ATE
R
R
E
W RIO
LO TE
FT DE
SO ND
P
E SA
C
DE HIN
T
373000
HIGH HAZLES SEAM
PARKGATE WORKINGS
SANDSTONE IN HIGHER ROOF
LOCAL EROSIVE LOWER
LEVEL CHANNELS
U
TOP HARD SEAM
Dn
?
?
REFERENCE
Dn
?
Dn
2 00
MBER
1
Dn
NOVE
1000m
Dn
0.3
0.3
Ds
Ds
U
Ds
370000
Ds
Ds
U
0.6
0.6
(i)
Fs
0.5
0.6
(i)
Fs
Sea
mS
plit
60c
ms
1.0
369000
cms
lit 30
p
S
Seam
U
TO ES
ED ERV
R
3
E S
0.
SF RE
AN CK
R
T BE
0.6
EL
W
500
Ds
TO
U
U
0.3
DATE JULY 2002
SCALE : 1/10,000
0
U
U
(i)
Fn n(i)
F
EP
DE
FT
SO
R
OO
FL
740
UK COAL MINING LIMITED.
THORESBY COLLIERY
DEEP SOFT SEAM
RECOVERABLE RESERVES
Dn
371000
705
35
PARKGATE SEAM
372000
688
691
14
DEEP SOFT SEAM
U
AL
CO
635
53
u
U
538
540
2
95
No. 2 SHAFT BOTTOM
No. 1 SHAFT BOTTOM
U
cm
30
481
LOCO ROAD HORIZON
U
T
LI
SP
480
1
57
U
U
U
U
368000
0.3
U
55
56
U
0.6
Figure 4-17
I5104C
470000
469000
468000
467000
U
466000
465000
464000
463000
U
462000
461000
460000
367000
Thoresby Colliery: Deep Soft Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 146
OLLERTON PARKGATE
WORKINGS
U
AIN
"M
54
KE
TA
IN
369000
SHAFT SECTION
U
U
STRATA
Thoresby Colliery
Depth
Metres
129
BUNTER SANDSTONE
U
129
131
2
UPPER MAGNESIAN LIMESTONE
1 in 70
Ollerton Colliery
(Closed)
U
No1
SHAF T
0
12
No2
SHAFT
U
367000
Ht
Interval
Metres
DRIFT
368000
Gt
Section
cm
1.3
Lice
nce
Bou
nda
ry
60
MIDDLE PERMIAN MARL & SAND
191
LOWER MAGNESIAN LIMESTONE
51
LOWER PERMIAN MARL
BASAL PERMIAN BRECCIA
5
1
242
247
248
U
11
0
110
232
90
0
10
Sherwood Grange
(Nursing Home)
U
366000
BILSTHORPE
PARKGATE WORKINGS
110
480
481
1
HIGH HAZLES SEAM
57
M
U S
IM E
X TR
A S
M L
F
O NTA
E O
N
LI R IZ
O
H
110
TOP HARD SEAM
538
540
2
S
95
LOCO ROAD HORIZON
635
110
53
Associated Sw
illey
Mansfield
Colliery
(Closed)
Sandstone on Seam
364000
r with
Floo
Hard
365000
120
Gt
No. 2 SHAFT BOTTOM
No. 1 SHAFT BOTTOM
110
362000
Rufford
Colliery
(Closed)
361000
705
35
of
Ro
PARKGATE SEAM
120
740
REFERENCE
SEAM CODE LETTER
HH
Boreholes
Gn
h
wit
San
dst
on
e
363000
691
DEEP SOFT SEAM
d
be
tur
Dis
l
ne
an
h
C
688
14
W
Faults:
Proven
Projected
Fault throws shown in Metres
Parkgate Seam shown in black
High Hazles Seam shown in red
Old High Hazles Seam Workings
12
0
Hb
2002
Face
11
0
2003
2004
2005
2006
UK COAL MINING Ltd.
THORESBY COLLIERY
HIGH HAZLES SEAM
RESERVE AREAS
Bilsthorpe Colliery
466000
465000
464000
I5104C
463000
Figure 4-18
462000
461000
460000
459000
458000
360000
DATE JULY 2002
REFERENCE:- SP/PG/250/19
SCALE : 1/10,000
0
500
1000m
Thoresby Colliery: High Hazles Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.9.3.6
PAGE 147
Geological and Reserve/Resource Conclusions for Thoresby
The last of the Parkgate panels in the north (190’ s) is currently being worked and is only
expected to have minor roof problems due to a roof coal split at the outbye end. The planned
production is then in the old Ollerton area, 42’ s-45’ s in the north of the block and 55’ s-57’ s in
the south. The structure is essentially proven by workings in the Top Hard Seam about 200 m
above, except for the northern parts of 43’ s, 44’ s and 45’ s where surface seismic has been
carried out. A channel sandstone belt crosses this area although the erosive effects on the
seam are not fully known.
In the south block, 55’ s could be affected by minor faulting, and 56’ s and 57’ s by a seam
split.
The main risk to the Draft Five Year Plan is the potential effect of the channel sandstone on
drivage and face cutting. Although the sandstone will be closer to the seam on 44’ s and 45’ s,
it is within one metre of the seam over much of the working area and may still have a
significant effect on the rates of development drivage.
The 45’ s panel should be considered very high risk due to the extensive close proximity of the
sandstone and possible faulting on the east side.
Currently there are no plans to work the Deep Soft Seam. Any future plans would have to be
considered high risk due to seam splits and possible sandstone channels in the roof and would
be constrained by the Parkgate workings about 35m below.
The High Hazles is so thin and potentially disturbed by channel sandstones in the roof and
swilleys in the floor that it should be removed from the reserves.
4.9.3.7
IMC Commentary on the Reserve/Resources for Thoresby
The first significant point to raise is that IMC believe that the High Hazles Seam with a
section of only 1.07m to 1.15m thick is too thin to be worked economically under present
conditions. This, along with the possibility of channel sandstones in the roof and swilleys in
the floor makes it unlikely that this seam will ever be worked. UK Coal plc have already
indicated that they do not intend to re-access the seam and hence IMC believe that this seam
should either be deleted for the assessment or designated as mineral potential.
The Parkgate Seam is the prime seam at Thoresby and to continue production in this seam the
mine will have to transfer the production faces into the Ollerton Colliery reserves areas
(Zones En and Es). These zones are not without geological risk as mentioned earlier in the
text (refer 4.9.3.6). Zones Eni, Enii, Eniii and Eniv have been categorised as probable reserve
by UK Coal plc based on the degree of geological knowledge, and although Eniii and Eniv
will be affected by a channel sandstone in the roof of the seam, the relaxations on the
tonnages for these zones have taken this into account. It is the opinion of IMC that these
zones stay in their present category.
However there is a case for zone Esii in the very south of the mine to be downgraded to
mineral potential based on the lack of geological knowledge and on the difficulty of access to
the zone especially after the panels laid out in the area have been worked. Zone Env in the
east also has some doubt about the structure in the zone and the possibility of laying out
panels. However this will be accessible as the workings progress and IMC see no reason at
present to change its category.
In the Deep Soft Seam all the zones defined have been included as indicated resource as the
degree of knowledge of these zones is adequate for this categorisation.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 148
However, two major geological factors affect most of these zones. Firstly there is a channel
sandstone that overlies part of Zone Fni and most of Zones Dn and Ds. These zones therefore
have the risk of erosion into the seam. Secondly and perhaps more importantly Zones Fs and
Ds show panel layouts within an area of splitting Deep Soft Seam with the dirt parting within
the seam ranging from 0.30m to 0.60m within a seam section of 2.00m or less. UK Coal plc
estimate that these zones are 1.90m with 1.45m of coal and 1.80m with 1.35m of coal
respectively with the dirt band being between 0.30m and 0.40m from the top of the seam.
It is the opinion of IMC that these zones are unfavourable and probably too dirty to work
viably. However the seam is at present being reviewed for its mining potential and the
company has shown intent to work similar sections in the same seam at Welbeck. Therefore
the category of Indicated Resource is regarded as being correct for the present time.
Zone Fn is also partly affected by this dirt split in the seam whereas Zones Dn and C have a
thinner seam section due to a reduction in thickness of the lower bed of the seam. IMC also
consider that these zones are categorised correctly.
In summary, the following table categorises the coal at Thoresby taking into account the
comments above
Table 4-54
Summary of IMC Reassessment of the Thoresby Reserve/Resource
(01/12/02)
Million Tonnes
Seam
Reserve
Resource
Total
High Hazles
Mineral Potential
8.092
Deep Soft
7.272
7.272
Parkgate
6.398
3.087
9.485
2.163
Total
6.398
10.359
16.757
10.255
4.9.4
MINE CHARACTERISTICS AND CONSTRAINTS
In the past, Thoresby has been a highly successful colliery. It has now almost exhausted all its
original reserves in the Parkgate. Future production is based on working an area of adjacent
coal in the Parkgate left by Ollerton Colliery. Access has been made into these old workings
and much of the infrastructure that is required has been recovered. The first face in this area,
42’ s, is planned to use the existing gate roads previously driven by Ollerton before closure.
Work is well under way to recover both these roadways and a new face line will be driven in
early 2003. Good conditions were found in both of these roadways, with additional supports
being set as they are recovered. Similar conditions were also observed in the main
infrastructure roadways, which are required to support up to seven planned faces in this area.
The first production face is planned for June 2003 and early indications are encouraging.
Present production plans for the Ollerton area are based on sustaining an output of 1.6Mt/a for
up to five years. Unfortunately prospects further east deteriorate rapidly; the seam splits to
the east and faults are evident in the north-east.
UK Coal plc are considering the potential for longer-term production from the Deep Soft
Seam some 35m above the Parkgate. Layouts for longwall panels would generally be
confined to those previously taken in the Parkgate seam. The potential for the Deep Soft
Seam has to be set against present data which shows the seam to be generally thinner at 1.30m
to 2.10m. It is also subject to serious splits (resulting in a high ash product) and sandstone
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 149
channels above the seam in some areas. The Deep Soft is also high in sulphur and chlorine
and it would be advantageous from a quality point, to work both seams simultaneously.
Viable options in the High Hazels Seam are severely restricted by its limited thickness
(maximum 1.10m), and cost of access and development.
Over the years Thoresby has had substantial investment in its infrastructure. This includes a
coal clearance system with bunkers to support saleable outputs in excess of 1.6Mt. In the
medium term, much of the development for replacement faces will be recovery of existing
roadways. If there are no serious deterioration in conditions inbye to those already observed,
this may allow some cost savings.
With the exception of localised problems associated with the changing position of the
sandstone strata relative to the top of the Parkgate Seam, conditions in the gate roadways are
generally good throughout. This is reflected in the relatively high drivage rates achieved at
Thoresby.
Manriding and materials supply to the Ollerton connection is by locomotive haulage. Rubber
Tyred Vehicles (FSV’ s) are used inbye to service developments and the future faces. The
flexibility of FSV’ s has increased the efficiency of face installation and salvage.
By the end of 2003 all production and development should be concentrated in the Ollerton
Parkgate area. Concentration in the Ollerton Area should result in much more rationalised
approach to production and development.
4.9.4.1
Ventilation
Parkgate workings in the Ollerton Area are prone to problems of gas emissions from old
workings in the Ollerton Parkgate seam. Future workings will require diligent control of
ventilation and methane drainage to ensure that this does not present a safety hazard and a
constraint on production. These old workings, situated to the rise side of the present working
area, will require monitoring at all times and in particular during periods of rapidly falling
barometric pressure.
As the sandstone in the roof measures comes closer to the top of the Parkgate seam, the risk of
frictional ignitions will increase. Sandstone is present in the immediate roof of the planned
faces 43’ s, 44’ s and 45’ s. UK Coal plc is aware of the potential risk and corrective action will
be taken to reduce risk, maintaining adequate ventilation throughout the cut area on the
faceline.
The present and last Parkgate face in the north-west will finish production in 2003 and once
sealed the booster fan will need to be reduced in duty or stopped to ensure sufficient airflow is
available in Ollerton area.
4.9.4.2
Subsidence
Parkgate Seam
Reserve Zone Cni: The current panel 190’ s will be the last to be worked in this area. The
workings are mainly under woodland and will not cause any land drainage problems. This
panel will affect part of Clumber Lake, which is situated in a National Trust area and a ‘Site
of Special Scientific Interest’ , and a Restaurant and Chapel.
Costs for mining subsidence damage and damage preventative works are estimated to be 65
pence/t.
Reserve Zone En (i), En (ii), En (iii) and En (iv): The panels in these areas are in the fiveyear development plan and will generally be worked under agricultural land but the villages
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 150
of Walesby and Kirton will be affected. Walesby, in the north west of the area will be affected
by 42’ s Panel, whilst Kirton in the south of the area will be affected by 43’ s, 44’ s and 45’ s
panels.
44’ s panel will also undermine a water main of 0.6m diameter. The affect on the low volume
Bevercotes Beck that traverses the area will be minor.
Subsidence damage costs are estimated to be between 30-40 pence/t.
Reserve Zone Es (i) and Es (ii):
55’ s panel and part of 56’ s panel fall within the fiveyear development plan with the remainder of 56’ s panel and 57’ s panel following on. 55’ s
will work under a semi underground reservoir, which will require preventative measures
costing in the region of £350,000. Workings in 56’ s and 57’ s panels will be under
agricultural land causing possible land drainage and fissuring problems, especially where
workings are associated with pillars in the Top Hard Seam.
The southern part of Es(ii) will work mainly beneath agricultural land but will also affect the
village of Kneesall in the south east corner of the block.
Overall, the subsidence damage costs are estimated to be low at 10 pence/t.
4.9.4.3
Coal Preparation Facilities
Thoresby Colliery has facilities rated at 700t/h, equating to around 70,000t/w or 3.36Mt/a.
The operations include dry fines extraction, twin stream Baum jig, froth flotation and water
clarification. The main product is PSF, a blend of dry fines and cleaned small coal. The
larger fractions are for the domestic market.
4.9.5
4.9.5.1
HISTORIC PERFORMANCE
Production
Table 4-55
Historical Production Performance at Thoresby
Thoresby
1999
2000
2001
Actual Output
million tonnes – saleable
1.665
1.772
1.266
Budgeted Output
million tonnes - saleable
1.750
1.700
1.600
Difference
million tonnes - saleable
-0.085
+0.072
-0.334
Production in 2001 was restricted to 1.266Mt. This was mainly due to a gap in production
taking place in the early part of the year, 192’ s face being developed too late to provide a
direct replacement to 188’ s. 192’ s has a face run of almost 2.5km and its development
programme was particularly onerous. The early part of 192’ s production was also affected by
adverse geology depressing face performance.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.9.5.2
PAGE 151
Development
Table 4-56
Historical Development Performance at Thoresby
Thoresby
1999
2000
2001
Actual Developments
metres
5,973
5,491
4,206
Budgeted Developments
metres
9,292
5,514
4,828
Difference
Metres
-3,319
-23
-622
The shortfall in 1999 is mainly attributable to a change in plan with the re-scheduling of the
entry and development of the Ollerton take. The reduction in development requirement in
2002 reflects the re-use of the old Ollerton infrastructure and 42’ s gate roads. The
reclamation of these roadways does not appear within the development statistics. The recent
shortfall has been caused by difficult conditions delaying the establishment of 43’ s gate road
drivages.
4.9.6
FUTURE MINING PROJECTION
The mine is currently working the most northern part of the take, which reaches exhaustion in
mid 2003. The last two faces, 192’ s and 190’ s were originally allocated to Welbeck and are
some 10km from the mine entries. From mid 2003 onwards production is to be maintained
from the Parkgate Seam in the old Ollerton take, re-using part of the closed colliery’ s
infrastructure. The mine has connected into the old Ollerton main roadways and is in the
process of repairing and re-establishing them for future use.
A maximum of seven faces are planned to be worked in the Ollerton area, eventually
standardising face length at 295m. Output at 1.6Mt/a to 1.7Mt/a is planned around a single
face strategy. Assuming that all the faces can be economically worked then the area will
reach exhaustion in late 2008. Currently there are no plans to access and work the Deep Soft
to perpetuate the mine beyond this time.
4.9.7
4.9.7.1
PRODUCTION AND DEVELOPMENT FORECASTS
Production
The draft Five-Year schedule is as follows:
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table 4-57
Face
Tonnes
in Panel
PAGE 152
Draft Five-Year Schedule
2002
2003
2004
2005
2006
Development (metres)
1,816
6,655
3,750
5,518
6,351
Total Output (Mt)
1.650
1.606
1.600
1.755
1.626
North West
192’s
190’s
1,598,000
Ollerton
42’s
856,000
43’s
1,466,000
44’s
1,721,000
45’s
897,000
55’s
1,205,000
The Draft Five-Year Plan shows the continuation of a single retreat face utilising two sets of
equipment to avoid gaps in face production.
Output for 2002 is expected to be around 1.65Mt compared to a budget of 1.8Mt. The last
face in the North West Area, 190’ s is currently in production; and although performing well it
is not achieving the rates attained by previous faces in recent years. This, coupled with less
coal produced from developments, has resulted in the shortfall in production against plan.
From mid-2003 onwards production is to be maintained from the Parkgate Seam in the old
Ollerton take, re-using part of the old Ollerton infrastructure roadways that have been recently
accessed and are in the process of being recovered.
The first face in the area, 42’ s, had been in production at the time of Ollerton’ s closure in
1994 and the gate roadways are currently being prepared for re-use; 42’ s has a face length of
279m and a run of 1,130m. The planned extraction height of 1.95m contains 1.85m of coal.
The panel is estimated to contain some 856,000t of saleable coal and phased at 13 shears per
day is planned to take production through to February 2004 when it is replaced by 43’ s which
is currently being developed.
43’ s Face is confined to a length of 270m due to the availability of powered roof supports;
however, subsequent faces are planned at 295m to maximise extraction. A total of seven faces
is potentially available within the Ollerton take; however, the most south-easterly panel, 57’ s,
must be regarded as speculative due to seam splitting and thinning. Assuming all the panels
are worked other than 57’ s, the mine will probably reach exhaustion in early 2008.
4.9.7.2
Development
A large proportion of the development work completed in 2002 is associated with the
recovery of infrastructure and gate roads within the old Ollerton workings. This has limited
the driving of new roadways to only 1,816m. 42’ s gate roads are currently being reestablished by excavating floor lift and setting additional roof bolts. Sections of the gate
roads have been waterlogged and have required de-watering.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 153
The annual development required to support the production plans from 2003 onwards is
shown to fluctuate between 3,750m (2004) and 6,655m (2003) per annum. In addition there
is a continuation of the detailed programme of roadway repairs, recovering the old Ollerton
infrastructure.
Four UK Coal plc heading teams are deployed on roadway drivage and a fifth on face salvage
/ installation. Trunk roads and initial gate road development, which are supported by
conventional steel arches, are phased at up to 25m/week and gate roads, which use bolting as
the primary means of support, are phased normally at 65m/week.
Exceptions to this are 43’ s Supply gate and 44’ s Loader gate, which are phased at 67m
reflecting the onerous development programme required for these faces.
The development programme for all the planned faces is shown to be completed by mid 2007.
This assumes that 57’ s will be able to be worked. If this is not the case, all roadway drivage
work will finish at the end of 2006 with the completion of 56’ s development.
The plans do not include the access and development of the Deep Soft to maintain production
at the mine following the exhaustion of the Parkgate in Ollerton. The seam is relatively thin
and is not considered to be a viable proposition. To maintain output levels at current levels
would require the adoption of a two-face strategy with its attendant increase in costs.
However, UK Coal plc has indicated that they intend to examine the feasibility of working the
Deep Soft Seam.
4.9.7.3
Risk
Thoresby Colliery is planned on a single face strategy at outputs ranging from 1.6Mt/a to
1.75Mt/a over a five year period.
From 2003 onwards all output will be produced from faces located in reserves left following
the closure of Ollerton Colliery in 1994. Thoresby is currently de-watering and recovering
the main roadways in this area.
The principal geological risks in the Ollerton Area are the deteriorating seam sections at the
inbye ends of 43’ s, 44’ s and 45’ s panels where the seam section is expected to be less than
1.6m and an erosive channel sandstone that is also expected to affect the same panels.
Although the erosive affects on the seam from this channel have not been quantified in this
area, any intrusion of sandstone into the seam will pose a risk to production and will only be
identified by development drivages or working faces.
Faulting has also been identified from overworking in the Top Hard and although the panels
are laid out in probable fault free areas, 45’ s face is at risk from faulting that may extend onto
the panel.
Workings in close proximity to old wastes are prone to problems of gas emissions. The
Parkgate workings in the Ollerton Area have suffered from these problems in the past. Future
working will require diligent control of ventilation and methane drainage to ensure that gas
emissions do not present a risk to safety or production.
4.9.7.4
Longer Term Plans
UK Coal plc, as has already been stated, are to review the potential and feasibility for future
production from the Deep Soft Seam.
4.9.8
OPPORTUNITIES FOR FURTHER INVESTMENT
Another consistent performer, Thoresby suffers mostly from it’ s own success in that it is
running out of accessible reserves. Over the past four years it has accumulated substantial
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 154
profits despite one poor year in 2001 when it made a small loss. Next year, it is budgeted to
continue at the current high production level of 1.6M/t and continue to make profits.
It is regrettable that this mine is now in the situation where it has difficulty in putting forward
any capital schemes. It is evident that, on past performance, the mine can generate enough
cash to contribute to a scheme.
In mid 2003 output will transfer from the current working area to the Ollerton Area that is
currently being re-opened and developed. It is anticipated that this area will sustain the mine
until 2008 when it will reach exhaustion. No major investment has been included within the
plans, the bulk of the expenditure in developing into the new area having already been spent.
The withdrawal from the existing area will also provide for the salvage and transfer of
equipment.
As previously stated current mine plans do not include the access and development of the
Deep Soft to maintain production following the exhaustion of the Parkgate in Ollerton.
However, UK Coal plc has indicated that they intend to shortly examine the feasibility of
working the Deep Soft Seam.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.10
WELBECK COLLIERY
4.10.1
BRIEF DESCRIPTION OF SITE
PAGE 155
Welbeck Colliery is located in Nottinghamshire, 10.5km north-east of Mansfield, close to
Meden Vale village. An access road for heavy goods vehicles has been made to the A616,
which passes some 1km north of the mine site.
The colliery was established between 1912 and 1915, since when three seams have been
worked - Top Hard, Deep Soft and Parkgate. The mine entries consist of two 6.1m diameter
shafts, No 1 and No 2, which are 660m and 653m deep respectively.
The main colliery site covers an area of some 29 hectares and has a comprehensive range of
surface buildings and facilities including a coal preparation plant, hard standings and run of
mine stockpile. In addition the mine has coal-stocking areas totalling around 10 hectares and
a further 97 hectares mainly of spoil heaps.
Production commenced from the Parkgate seam in 1992 after the completion of two drifts
from the Pit Bottom area at the Top Hard horizon. RJB Mining (later to become UK Coal
plc) took over the mine in January 1995. The mine, at the time of privatisation, was in full
production.
4.10.2
MINE BOUNDARIES
The licence area has a boundary with the abandoned Manton Colliery in the north,
neighbouring Thoresby Colliery also provides a boundary to the south with a geologically
disturbed area to the east. Operations in the Parkgate have been split into two areas north and
east of Welbeck shafts. Production in the east, adjacent to Manton has now ceased and the last
face is being salvaged.
4.10.3
GEOLOGICAL ASSESSMENT OF THE MINE
Welbeck lies in the central Nottinghamshire part of the eastern Pennine Basin Coalfield,
between Mansfield and Worksop. It is bounded by the closed Manton Colliery to the north
and the active Thoresby Colliery to the south and east. Large faults lie to the west, but the
effective western boundary is seam deterioration. The Coal Measures are gently dipping
beneath unconformable Permo-Triassic formations, which are locally overlain by thin
superficial deposits. The reserve seams lie at depths between 700m and 800m below surface.
The local Coal Measures are typical for this part of the coalfield. There are no igneous
features of mining significance.
4.10.3.1
Structure
The Permo-Triassic formations dip gently and consistently eastwards across Welbeck,
whereas the underlying Coal Measures have variable dip directions, with an overall
progression to greater depths in the east. Across much of the area, the Coal Measures form a
roughly concentric "low” , between the Kiveton-Bothamsall Anticline to the northeast, and the
Whitwell Anticline to the southwest (both folds being largely outside the area of mining
interest). The bedding dips, and the faults, are largely proved by mine workings, particularly
in the Top Hard and Parkgate seams. Throughout Welbeck, fault styles are essentially normal.
Fault density is very low. Most faults strike NW-SE or SW-NE; maximum throws are
typically <10m.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.10.3.2
PAGE 156
Seams in Reserves
The following seams are considered to be in the reserve classification for this mine. These
are: •
Deep Soft Seam
•
Parkgate Seam
Deep Soft Seam Characteristics
The roof is generally mudstone or silty mudstone, passing up to stronger siltstone and
sandstone beds, but on 207’ s and 209’ s panels, erosive channel sandstones may affect the
seam. This sandstone is expected to be in the drivages or just above the horizon that the roof
is bolted from but may in parts be erosive and come down into the top of the seam.
The seam contains several dirt partings and the total thickness varies from 1.66m-2.50 m, of
which the coal thickness is 1.33m-1.85 m. In the Draft Five Year plan area, the seam should
range from 2.15m-2.50 m of which 1.70m-1.80 m should be coal.
As mined ash
18-39%
Coal ash
6-15%
Sulphur
2.0-3.0%
Chlorine
0.3-0.6%
The floor is generally a weak seatearth mudstone with the occasional development of a thin
floor coal.
Parkgate Seam Characteristics
The roof is generally mudstone up to 1.50m thick passing up to siltstone. This is the typical
roof for the Parkgate Seam at Welbeck. However over the area of zones CCii and CCiii small
braided channel sandstones are expected in the higher part of the roof measures in the
drivages. These are not expected to affect the seam. Details of the roof measures in Zones A,
Bn and Bc are not known
The seam contains several dirt partings and the total thickness varies from 1.65m-2.55m
(excluding Zone A), of which the coal thickness is 1.30m-1.98m.
As mined ash
24-33%
Coal ash
7-10%
Sulphur
2.3-3.0
Chlorine
0.3-0.5%
The floor is generally a weak seatearth mudstone up to 0.25m thick overlying stronger
sandstone/siltstone. Again, details of the floor measures in the same three zones to the north
are not known.
4.10.3.3
Reserves/Resources Assessment
In the 1998 assessment the Deep Soft had not been worked, and was included as Indicated
Resources. Workings since 1998 have concentrated in the Parkgate Seam and these reserves
are being depleted.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 157
Position with regard to Reserves in 1998
The reserves/resource available at Welbeck in 1998 were as summarised in Table 4-58 below
based on the knowledge at that time. These have changed up to the last assessment in 2002 in
the light of more detailed information and a comparison will be made of the changes later in
the report.
Table 4-58
Welbeck Reserve/Resource Summary (01/07/98)
(Source: RJB Mining)
Million Tonnes
Seam
Reserve
Resource
Total
12.740
12.740
Deep Soft
Parkgate
7.080
8.952
16.032
Total
7.080
21.692
28.772
Mineral Potential
Position with regard to Reserves/Resources in 2002
The Parkgate Seam is being worked in the Five Year period, and these areas are all shown as
proven and probable reserves.
The Deep Soft is planned to be worked within the Five Year period, and in the central block
(Zone Gs and Gn) the seam is considered to be probable reserves. Indicated resources are
shown for all other areas in the Deep Soft at the mine.
A summary of the 2002 assessment is shown in Table 4-59 below
Table 4-59
Welbeck Reserve/Resource Summary (July 2002)
(Source: UK Coal)
Million Tonnes
Seam
Reserve
Resource
Total
Deep Soft
5.426
9.107
14.533
Parkgate
3.035
8.938
11.973
Total
8.461
18.045
26.506
Mineral Potential
Changes Between Reserve Assessments
The reserve in the Deep Soft have increased from zero in 1998 to 5.426Mt as a result of the
upgrading of resources to reserves, and the transfer of reserves from Thoresby. The
proportions of this increase is shown below:
Zones upgraded
+3.490Mt
Zone Fni from Thoresby
+1.936Mt
Total
+5.426Mt
The rest of the tonnages are assessed as resources and are similar to the 1998 position. Apart
from the overall increase with the transfer of the Thoresby Deep Soft to Welbeck the total
tonnages are only affected by very minor layout changes that result in an increase of
approximately 0.1Mt.
The Parkgate Seam reserves have decreased by 4.045Mt from 7.080Mt to 3.035Mt. This is as
a result of working the seam. However there has been changes in zone boundaries and layout
and the inclusion of a new zone, Zone D, that has generated a further 1.50Mt of coal.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 158
Zones worked
-5.568Mt
New/enlarged zones
+1.523Mt
Total
-4.045Mt
Resource Zones
The Deep Soft resources have decreased by 3.633Mt from 12.740Mt to 9.107Mt mainly due
to the upgrading of resources to reserves. However Zone Ce was also abandoned and that has
also reduced the resource in this seam.
Zones upgraded
-2.947Mt
Zone Ce abandoned
-0.686Mt
Total
-3.633Mt
The Parkgate resources have only been reduced by 0.014Mt, from 8.952Mt to 8.938Mt which
is due to a minor recalculation.
4.10.3.4
Exploration
No surface exploration is planned in the near future at the mine and the only exploration will
be in-seam seismic surveys as required as the developments progress.
4.10.3.5
Other Seams of Interest
There are no other seams of interest.
4.10.3.6
Geological and Reserve/Resource Conclusions for Welbeck
The Parkgate seam will be worked out within the Five Year period, and be replaced by
production from the Deep Soft Seam. Both seams are largely overworked and the main
faulting pattern is known.
The Parkgate 312’ s panel, which is the replacement panel for the current 310’ s Parkgate
panel, is expected to be affected by faulting in the northern part and this is reflected in the
reserves statement (Zone CCiii). If as expected the fault throw reaches seam thickness, this
would affect progress and quality. The 314’ s panel (Zone D) may be affected by minor
faulting and will be working in an area where the seam begins to deteriorate, giving a seam
ash of 20-25%.
A number of the Deep Soft panels may be affected by minor faulting although it may be
possible to reduce the risk using in-seam seismic. This seam has a significant dirt content
which could be higher if the projected seam split positions vary adversely.
The areas to be worked contain various geological problems, but these are largely predicted.
The main risk is the effect of faulting on 312’ s Parkgate panel as this is the next working
district. 314’ s replacement should be available if 312’ s has to stop early.
The reserves assessment shows some areas of coal in indicated resources which may be better
considered as mineral potential. These are Deep Soft Zones A, Bn and Bs and Parkgate A, Bn
and Bc, which are all likely to have geological problems and access difficulties.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 159
Table 4-60
SEAM
Zone
Deep Soft
A
Bn
Bs
Ce
Cw
Gn
Gs
Hs
Hn
Parkgate
A
Bn
Bc
Bs
Cniii
Cci
Ccii
Cs
1998
RESERVE (Mt)
RESOURCE (Mt) Mineral Risk Factor Block
or
Proven Probable Measured Indicated Potential Tect Sed
Zone
(Mt)
Panel
1.573
2
4
B
A
4.231
2
4
B
Bn
1.143
2
4
B
Bs
0.686
2
4
B
1.108
2
4
P
Cw
Cwi
Fni
0.851
2
4
B
Gn
0.989
2
4
B
Gs
0.727
2
4
B
Hs
1.433
2
4
B
Hn
7.091
1.109
0.752
1.770
0.691
0.831
3.409
0.379
3
3
2
2
2
1
2
3
5
3
2
3
2
2
B
B
B
P
P
P
P
2
2
P
2002
RESERVE (Mt)
RESOURCE (Mt) Mineral Risk Factor Block Change
Proven Probable Measured Indicated Potential Tect Sed or Panel
(Mt)
1.573
2
4
B
No change
4.231
2
4
B
No change
1.143
2
4
B
No change
-0.686
0.496
3
4
P
-0.612
0.533
2
4
P
+0.533
1.936
2
3
P
+1.936
1.676
2
3
P
+0.825
0.785
2
4
P
-0.204
0.725
2
4
B
-0.002
1.435
2
4
B
+0.002
A
Bn
Bc
Cci
Ccii
Cciii
7.091
1.109
0.738
I5104C
2.980
4.100
8.952
3
3
2
3
5
3
B
B
B
0.529
1
2
4
1
2
2
P
P
P
0.994
3
2
P
0.730
0.782
D
TOTAL
Welbeck Reserves and Resources Comparison
1.512
6.949
No change
No change
-0.014
-1.770
-0.691
-0.101
-2.627
+0.529
-0.379
+0.994
Reason for Change
Abandoned
Zone split
New zone
Transferred from Thoresby
Larger zone
Smaller zone
Re calculated
Re calculated
Re calculated
Worked
Worked
Worked
Worked
New zone
Worked
New zone
18.045
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
464000
463000
462000
461000
460000
459000
458000
457000
456000
455000
454000
PAGE 160
453000
452000
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
381000
No.2 Shaft Section
Strata
Surface Level 61.23m AOD
380000
Section Interval Depth
cms Metres Metres
Permo Trias
Bunter and Middle
Permian Marl
93
Lower Magnesian Limestone
24
Lower Permian Marl
35
152
37
Coal Seam
379000
93
117
140
189
60
A
Manton Colliery
Top Marine Band
249
252
3
124
378000
Wales Seam
86
Mansfield Marine Band
376
21
5
397
402
39
Swinton Pottery Seam
377000
Clowne Seam
Main Bright Seam
Two Foot Seam
Manton Colliery
Parkgate Workings
BN
Manton Colliery
Parkgate Workings
376000
110
51
441
25
466
21
13
487
500
57
High Hazles Seam
110
Pit Bottom Manriding Level
Top Hard Seam
No.2 Shaft Pump
176
Deep Soft Seam
Parkgate Seam
200
230
557
624
635
18
653
155
808
842
34
Reference
Manton Colliery
Parkgate Workings
Welbeck Top Hard
Workings
Seam 190cms
Se
am
Seam
200cm
Braided Sandstone
Channels in Upper Roof
Locally Erosive into Drivage
Roof Coal Split 50c
m
374000
373000
?
Welbeck Top Hard
Workings
372000
Cc Cciii
i
E
STON
OF
SAND PER RO
DED
BRAI NELS IN UP
CHAN
SANDSTONE CHANNEL WITHIN
OR CLOSE ABOVE DRIVAGE
Seam Code Letter
Faults
U
U
UU
Top Hard Workings
U
Cc
ii
Braided Sandstone
Channels in Upper Roof
Locally Erosive into Drivage
UU
U U
U
U
m
200c
Seam
U
U
371000
D
Seam
Face
PG310’s (R)
PG312’s (R)
PG314’s (R)
2002
2003
2004 2005
2006
M J S D M J S D M J S D M J S D M J S D
Deep Soft
WATERLOGGED
AREA
WELBECK
COLLIERY
UK COAL MINING LTD
am
Se
22
0c
m
m
0c
22
Se
am
WARSOP TOP HARD
WORKINGS
PG
Boreholes
18
0c
m
Parkgate
370000
71
78
BC
375000
176
WELBECK COLLIERY
U
PARKGATE SEAM
RECOVERABLE RESERVES
369000
Figure 4-19
I5104C
Welbeck Colliery: Parkgate Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 161
Possible Inferior
Chavery - Top Soft or
Top Soft - Roof Soft Available
No.2 Shaft Section
Strata
A
Surface Level 61.23m AOD
Bn
Permo Trias
Bunter and Middle
Permian Marl
93
Lower Magnesian Limestone
24
Lower Permian Marl
35
93
117
152
Split w
ithin T
30 cm op Soft
Top Marine Band
AF S.
LE TE
ER RA
O
W
I
LO ER
FT ET
SO D D
P
N
E A
DE INS
TH
m
Sea
ve
abo
se
lo
c
or
on
Silt
nd/Sa
e
n
o
dst
cm
San
TO 30
FT LIT
O
P
S S
EP AL
DE CO
R
O
O
FL
86
Mansfield Marine Band
376
21
5
397
402
39
Swinton Pottery Seam
176
Clowne Seam
Main Bright Seam
Two Foot Seam
110
51
High Hazles Seam
110
Pit Bottom Manriding Level
Top Hard Seam
No.2 Shaft Pump
176
Deep Soft Seam
Parkgate Seam
200
230
71
441
25
466
21
487
500
13
57
557
78
ilt
nd-S
m
e/Sa ove Sea
n
o
t
s
b
Sand r close a
on o
m
0.6
i
Fn
Gn
Gns
G
0.6
m
Hs
249
252
3
Wales Seam
0.3m
i
Fn
m
0.3
close
m
0.3
Hn
189
124
i
Cw
or
ndstone on
Erosive Sa e Roof Soft
abov
Cw
140
60
Ch
av
Sp ery/
lit To
50 p S
cm of
t
f Soft
/ Roo t
Soft
pli
Deep 50 cm S
37
Coal Seam
Bs
Top Soft / Roof Soft
Split 30 cm
DEEP SOFT WORKINGS
FROM MANSFIELD COLLIERY
Section Interval Depth
cms Metres Metres
DEEP SOFT WORKINGS
FROM CLIPSTONE COLLIERY
624
635
18
653
155
808
842
34
Reference
m
3.0
Seam Code Letter
DS
Surface Boreholes
Underground Boreholes
Faults
Parkgate Workings
Seam
Face
2002
2003
2004 2005
2006
M J S D M J S D M J S D M J S D M J S D
UK COAL MINING LTD
WELBECK COLLIERY
DEEP SOFT SEAM
RECOVERABLE RESERVES
Figure 4-20
I5104C
Welbeck Colliery: Deep Soft Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.10.3.7
PAGE 162
IMC Commentary on the Reserve/Resources for Welbeck
Welbeck has a limited life in the Parkgate Seam with only two panels remaining after the
present face finishes. Of these two panels, as laid out in the plan, 314’ s panel (Zone D) is at
higher geological risk. It is considered by IMC that the Parkgate zones in the plan are
categorised correctly.
However also shown are three zones to the north of the Manton Colliery workings that were
included in the Welbeck reserves statements before 1998. These are Zones A, Bn and Bc. It
is considered that these zones are very difficult to access and will involve lengthy drivage.
No geological plans were available for these zones although the geological risk assigned by
UK Coal plc to them is generally moderate for both structure and sedimentology. It is
however the access that is in question and IMC believe that these zones should be recategorised as mineral potential until a decision is made to look at the feasibility of accessing
them.
It is, however, the Deep Soft Seam that IMC have some concern about the geology of the
seam and its mining characteristics. In this seam zones Gn, Gs, and Fni are all planned in the
area of seam split that affects the eastward zones at Thoresby. One panel in Zone Gs is also
expected to have a channel sandstone over the whole panel with the associated risk of
possible erosion into the seam. This panel must be at high risk from both the sandstone and
the adverse variations in the position of the 60cm split line.
UK Coal plc recognise the fact that the section contains a thick dirt band and in spite of this
have included zones Gs and Gn in their five year plans for the mine. In doing so they have
taken into account the risk of the sedimentological uncertainty to the zones and shown an
intention to mine this seam. As the planned area is accessed and worked on three sides then
Zones Gn and Gs are categorised as probable reserve. For Zone Gn this is the correct
category, however as stated in the paragraph above, Zone Gs is at much higher risk and
should therefore be downgraded to resources until more information becomes available.
Zone Fni to the west of Gn is not included in the plan and is categorised as probable reserve.
IMC believe that it is prudent to show these reserves in the same light as those at Thoresby as
they are not presently accessed and will only be accessed if working in the splitting section in
the planned area is successful. It is therefore suggested that these be categorised as a
indicated resource for the present time as adverse variations in the split lines or the channel
sandstone could affect their workability.
Two further zones inbye of the present workings, Zones Hs and Hn, are shown as indicated
resource. However at present access is lost and there is no intention to re-access these areas,
(old workings between the planned working area and these zones is being actively flooded at
present). Therefore there is a case for moving these zones into mineral potential.
Finally, as in the Parkgate Seam, there are three zones north of the Manton workings in the
Deep Soft, Zones A, Bn, and Bs. Again these zones are at present inaccessible and would
involve kilometres of development drivage to access. The zones are also subject to seam
splitting and all show a significant sedimentological risk. Structural risk however is low due
to overworking in other seams. Again similar arguments apply as to the Parkgate in the same
area and these zones should be re-assessed as mineral potential.
In summary, the effect this has on the reserve statement is as follows
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table 4-61
PAGE 163
IMC Summary Re-assessment of the Welbeck Reserve/Resource
(01/12/02)
Million Tonnes
Seam
Reserve
Resource
Total
Mineral Potential
Deep Soft
2.695
2.721
5.416
9.117
Parkgate
3.035
3.035
8.938
Total
5.730
8.451
18.055
4.10.4
2.721
MINE CHARACTERISTICS AND CONSTRAINTS
The mine operates a single longwall face with two sets of face equipment and a manpower of
517. Output is expected to exceed 1.7Mt saleable at a production cost of less than £1.00 per
GJ. This is the lowest cost of production in all the deep mines in UK Coal plc.
The principal mining constraint for Welbeck is the depletion of Parkgate reserves. The
situation worsens from 2003 with the last face 314’ s being subject to faulting and in an area
were the coal contains more dirt in the mined section due to the seam splitting.
Other seam options for Welbeck appear extremely limited. An area of Parkgate further west
of Manton has been recognised but is not thought to be viable. The area is remote from the
present infrastructure at Welbeck and the costs of access are thought to be prohibitive. In
addition, a seam split reduces the height of coal in the cut section to 1.15m.
Another area of coal has been considered in the Deep Soft Seam with faces planned over the
previously worked Manton Parkgate faces. This has also been discounted primarily due to
high costs of access set against a relatively thin seam with a dirty section. The anticipated
mining section of 1.70m only contains 1.30m of coal with a high sulphur content of 3.0%.
Stability of roadways is also likely to be poor in areas affected by interaction from pillars in
the Parkgate Seam some 35m below. Interaction from some pillars left in the Top Hard Seam
may also have adverse affects.
The Welbeck Deep Soft resources are well scattered throughout the licence area. UK Coal
plc have defined an area of Deep Soft to the south-east of Welbeck shafts, which was
accessed and part worked some ten years ago. At that time production was based on a twoface strategy and output from the Top Hard faces were used to sweeten the dirtier Deep Soft.
The main intake and returns have been re-established and the locomotive haulage system is
being progressed along the north-east return. Work is now planned to re-establish the inbye
main roadways followed by relatively short drivages to access the two panels planned in the
south.
Whilst observing that there are a few and relatively localised areas requiring repair, the
majority of the roadway circuit in the Deep Soft was found to be in good condition.
Nevertheless, it is worth noting that some of the localised areas indicate damage directly
associated with the pillars in the Top Hard some 160m above. All the outbye coal clearance
conveyors have been installed as far as the junction to the inbye north-east intake. The mine
is also planning to install a conveyor booster drive at a midway position along the main intake
conveyor to effect an increase in conveying capacity. It is also planned to install a mechanical
bunker at the crosscut delivery end. When complete this installation will both meter and
bunker the ROM before being conveyed to the skip-winding shaft.
It is hoped that over the next few weeks manpower resources can be directed towards the
urgent work required recovering and fully developing this area of Deep Soft. This is
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 164
particularly important to the mine bearing in mind the limited production left in the Parkgate
Seam and the need for replacement. UK Coal plc may re-assess the present Deep Soft layout
because some of the proposed panels have a split in excess of 0.30m and in some parts over
0.60m in the mined section.
4.10.4.1
Ventilation
The present Parkgate workings will cease during 2004 and should be satisfactorily ventilated.
The last face PG314’ s may have sandstone in the worked section, which may give rise to a
frictional ignition risk.
4.10.4.2
Subsidence
Parkgate Seam
Two panels are planned to work in the Parkgate Seam. PG312’ s panel will undermine mainly
woodland although a small number of properties will be affected around Carburton village. A
small part of Clumber Park will be affected. PG314’ s panel will affect a few properties
around Budby village and the River Medan otherwise the area is mainly farmland with some
forest. Fissuring remains a possibility. Subsidence damage costs have been estimated to be
around 20 pence/t.
Deep Soft
Reserve Zone Gn and Gs: The four panels in this block are in the five-year development
plan. All four panels work under woodland with a small area of agricultural land. Apart from
a 500mm-diameter water main no other structures will be affected, but fissuring may occur at
the surface. Costs of mining subsidence damage are estimated to be low at less than 10
pence/t.
Reserve Zone Cw and Cw (i):
207’ s and 209’ s panels will work mainly under
woodland and agricultural land but the River Meden, a 450mm-diameter water main, Budby
water pumping station and a small reservoir will be affected. Both panels will also affect the
unclassified road from Meden Vale to Budby. Fissuring problems are not anticipated in this
area. The cost of mining subsidence damage is estimated to be less than 30 pence/t.
Reserve Zone Fn(i): The most northerly of the three panels in the block will mainly work
beneath woodland and agricultural land but will affect Thoresby Lake. Fissuring at the
surface is anticipated.
The two southern panels will affect woodland and agricultural land and the A616 Cuckney to
Ollerton road and its junction with the B6054.
The cost of mining subsidence damage is estimated to be low at 10 pence/t.
4.10.4.3
Coal Preparation Facilities
Welbeck has an old plant that has been renovated over the years. A new froth flotation plant
was installed in the early 80’ s, and the wash box was replaced with a larger unit to increase
the plant capacity together with the fines filtration capacity.
The plant has a nominal capacity of 500t/h of ROM, 125mm – 0. ROM from the mine feeds
out to a ground stockpile with the feed to the plant extracted at a controlled rate from a tunnel
under the stockpile. The ROM is screened at 125mm, the oversize being crushed and recirculated. Screen underflow passes over a dry fines extraction screen, the underflow is
bunkered; this is the dry fraction of the PSF blend. Screen oversize is fed to a three-product
washbox, currently operating as a two product box, the discard from which is dewatered prior
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 165
to being conveyed to the tip. The clean coal produced passes over a dewatering screen, and
then onto a classifying screen; the coarse fraction is out-loaded for further cleaning. The
smaller fraction, washed smalls are dewatered in centrifuges to form a cleaned constituent of
the PSF blend. Raw slurry is extracted from the wash water circuit, passed over a slurrydewatering screen and is added to the washed smalls prior to centrifuging, hence going into
the PSF Blend. There is a Hydrosizer Circuit built into the system with a bypass, which can
clean up the slurry should this be necessary at any time.
The feed to the flotation plant, a mid level siphon from the tower, gravitates to the flotation
cells, the recovered froth concentrate is pumped to vacuum drum filters producing a filter
cake which is added to the PSF. The tailing from the process gravitates into a water
clarification system; the surface water is reused in the plant, and the thickened sludge is
pumped to settlement lagoons, the decanted water being brought back into the system.
Graded coals produced are retreated in a Large Coal DM Plant located within the Welbeck
Colliery site. The plant, a three-product system, contract operated, re-treats all of the
domestic coal from all mines within the locality, producing a low ash good quality domestic
grades of fuel. The discard from the plant, middlings, is crushed and added to the PSF Blend
at Welbeck Colliery.
The mine currently produces around 2.8Mt ROM; this equates to approximately 65,000t/w,
which yields around 40,000 to 45,000 tonnes of saleable. Assuming the plant is available 100
hrs/w, it is capable of processing 50,000t/w. This is exceeded most weeks by as much as
10%. However, in the current conditions, there is a shortfall of 10,000t/w. Hence the Raw
Coal stock is currently standing at around 180,000 tonnes, and there is also a stock of 105,000
tonnes of PSF.
The plant needs help in the form of a small coal washing system, to produce additional
washed coal. This would allow the extraction of dry fines to be increased, adding capacity to
the processing facilities at Welbeck.
4.10.5
4.10.5.1
HISTORIC PERFORMANCE
Production
Table 4-62
Historical Production Performance at Welbeck
Welbeck
1999
2000
2001
Actual Output
million tonnes – saleable
1.191
1.379
1.494
Budgeted Output
million tonnes – saleable
1.625
1.270
1.430
Difference
million tonnes – saleable
-0.434
+0.109
+0.064
Production in 1999 was restricted by the working of PG308’ s, that had limited dimensions
and poor working conditions due to geological faulting. Output in 2000 and 2001 was
restricted by short face runs in the area being worked adjacent to old Manton Colliery. These
limited face runs resulted in high occurrence of face changes.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.10.5.2
PAGE 166
Development
Table 4-63
Historical Development Performance at Welbeck
Welbeck
1999
2000
2001
Actual Developments
metres
5,691
6,813
4,649
Budgeted Developments
metres
8,993
7,826
7,006
Difference
metres
-3,302
-1,013
-2,357
The shortfall in 1999 reflects a change in plan that was undertaken in response to the
difficulties encountered in the development of PG308’ s. A change in plan also occurred in
2001 when the method of developing the Deep Soft was revised. The original plans included
extensive drivage from the existing Parkgate infrastructure with a view to utilising the inbye
Parkgate bunker within the Deep Soft coal clearance. This was abandoned in favour of
confining the access to the re-establishment of the old Deep Soft infrastructure thus reducing
the development requirement.
4.10.6
FUTURE MINING PROJECTION
The strategy is to continue production from a single retreat face, utilising two sets of face
equipment to avoid production gaps. Two planned faces remain to be worked in the current
Parkgate area to the North East of the mine entries, namely PG312 and PG314. Maintaining
output at around 1.7Mt/a; these faces are planned to reach exhaustion by October 2004,
assuming PG314 achieves its full planned extent.
From October 2004 onwards production is planned to be maintained from the Deep Soft
Seam, the access drifts to which lie to the south east of the mine entries. As noted earlier, the
faces are to be accessed by extending the existing infrastructure that was originally abandoned
in 1995 and which is currently being re-opened, repaired and re-established.
The mining plan indicates production from the Deep Soft at around 1.53Mt/a to 1.57Mt/a.
Four faces are initially planned taking production to early 2007. Two further panels (DS246’ s
and DS244’ s) are proposed within the GDO Planning and Licence boundaries. These are to
be accessed by driving strategic roadways to the northeast from the current infrastructure. A
further five faces are tentatively shown as being accessed by extending these roadways north
east. These faces lie within Thoresby’ s GDO Planning and Licence Boundary and reserve
base.
4.10.7
4.10.7.1
PRODUCTION AND DEVELOPMENT FORECASTS
Production
The Draft Five-Year schedule is as follows:
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table 4-64
Face
Tonnes
in Panel
PAGE 167
Draft Five-Year Schedule
2002
2003
2004
2005
2006
Development (metres)
5,826
5,627
6,935
6,504
5,780
Total Output (Mt)
1.795
1.702
1.608
1.526
1.568
Parkgate
PG310
1,774,000
PG312
1,621,000
PG314
1,144,000
Deep Soft
DS219
997,000
DS207
697,000
DS221
1,039,000
DS209
792,000
PG310’ s, a 300m wide panel in the North East Parkgate has operated since October 2001 and
has provided all the face production in 2002 resulting in an estimated output for the year of
around 1.79Mt.
PG310’ s is planned to be replaced by PG312’ s, the last face to the north, in February 2003.
PG312’ s is 244m wide and has a panel run of 2,256m. The worked section of 2.55m contains
1.95m of coal and it is estimated that the panel contains around 1.62Mt of saleable product.
This tonnage seems high from the anticipated coal in section and is equivalent to a SG of
1.51. Working three shifts, PG312’ s is phased at 16 shears per day compared to 11.4
achieved on PG310’ s. Assuming that the planned stripping levels are achieved then PG312’ s
will reach exhaustion in January 2004. PG312’ s will negotiate some minor faulting
encountered in the return gate drivage, and this has been allowed for in the production
schedule.
PG312’ s is to be replaced in January 2004 by PG314’ s, which will be the last Parkgate face.
The face is positioned to the south of the current workings and is accessed from close to the
base of the Parkgate Access Drifts and 1,000 tonne bunker. The face is positioned between
faulting and is expected to be affected by several minor faults; has not appeared on previous
plans and must be regarded as being at relatively high geological risk. The face is shown to
be 285m wide and has a potential run of 1,437m but the inbye 180m is at particular risk from
faulting.
PG314’ s panel is shown in the plan to contain 1.144Mt and, phased at a maximum 13.2 shears
per day (7,480t), has a planned life of around 8 months. It must be noted that the reserve
assessment only shows 0.994Mt being available within PG314’ s panel reflecting the
geological risk. The face will cease production in October 2004 when it is replaced by
DS219’ s, which is the first of a succession of faces planned to be worked in the Deep Soft.
DS219 and DS221 lie to the south of previously worked faces in an area where the seam splits
above 0.60m. It is important to note that although the production schedule attributes some
2.036Mt to these two panels, only 0.785Mt (equivalent to only 38.6% of that shown in the
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 168
schedule) has been included as probable reserves within the UK Coal plc Reserve
Assessment. This reflects the significant geological risk.
4.10.7.2
Development
In general four UK Coal plc development teams, are deployed throughout the five-year
period. These are supplemented on occasion by a fifth team of outside contractors. The
annual development requirement will vary between 5,627m in 2003 and 6,935 in 2004. Gate
road drivages are generally phased at 70m/w. Other types of development range from 15m/w
for an arched scouring, to 45m/w for face headings.
In the latter part of 2002 four teams have been deployed to develop PG312’ s and PG314’ s
within the Parkgate. In addition a ‘skeleton’ fifth team has been working towards reestablishing the old infrastructure within the Deep Soft.
The two teams developing PG314’ s remain within the Parkgate area until October 2003
before being transferred to the Deep Soft to join the two teams that will be deployed there in
March and June 2003, when they become available from the Parkgate. In addition a
contractor team is shown to commence work on the Deep Soft infrastructure in March 2003.
At present two JCM18 and two MD1100 heading machines are deployed to complete the
development of PG312’ s and PG314’ s. An LH1300 Roadheader is also being installed within
the Deep Soft to be used to repair the intake infrastructure. The plan shows the JCM18’ s
being replaced by MD1100’ s to develop the Deep Soft Seam. These machines have on-board
bolters better suited to the anticipated drivage conditions expected within the Deep Soft. It is
important to note that, in common with other mines within the UK there is a shortage of men
able to use hand-held drilling machines because of the legal implications of ‘vibration white
finger’ .
A significant amount of work requires to be done in recovering and re-establishing the old
Deep Soft infrastructure in the first instance to undertake the development of DS219, and then
to enable production from the area to commence. These works include the uprating of the
main rope haulage, the extension of the locomotive system, the construction of locomotive
and free steered vehicle garages, the establishment of the mineral conveying system and the
build-up and installation of ventilation booster fans. The increase in manpower to 571
required in the middle of 2004 reflects the amount of work that required in a very short time
scale.
4.10.7.3
Risk
At present the mine has activities spread over a wide infrastructure as the mine continues in
the Parkgate whilst opening up the Deep Soft and is stretched in resources, in terms of
manpower, plant and machinery. The transitional period to early 2005 is particularly
demanding, however, once activities have ceased in the Parkgate area, large parts of the
infrastructure can be vacated and sealed off, making potentially significant savings.
As outlined previously PG314’ s is at significant risk from faults jeopardising output in 2004.
The development of the Deep Soft is particularly onerous with no flexibility. Should the
panel run of PG314’ s be foreshortened, it will probably cause a gap in face production.
DS219’ s and DS221’ s are at significant risk from the upper dirt band within the seam
increasing to over 0.60m. It must also be noted that beyond the five year period the planned
panels currently within the Thoresby boundaries are at high risk from sandstone/siltstone roof
features, particularly as the workings progress to the northeast.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.10.8
PAGE 169
OPPORTUNITIES FOR FURTHER INVESTMENT
This mine is currently operating at the lowest production cost in UK Coal plc. This mine has a
potential to generate cash and justify capital investment. There are a number of schemes
possible at the mine ranging from access to new working areas to surface investment to
extend tipping space.
The mine is to transfer production from the Parkgate seam to the Deep Soft in the latter part
of 2004. To accomplish this a significant amount of work requires to be done in recovering
and re-establishing the old Deep Soft infrastructure, in the first instance to undertake the
development of DS219, and then to enable production from the area to commence.
These works will require significant investment including the up-rating of the main rope
haulage, extension of the locomotive system, construction of locomotive and free steered
vehicle garages, establishment of the mineral conveying system and the build-up and
installation of ventilation booster fans. It is estimated that uprating the conveying system will
cost around £1M for a booster drive plus £1.5M for a bunker. The bulk of this expenditure is
planned to be undertaken in 2004 and may be regarded as Category 2 investment. In addition
around £1M will be required to extend the existing tip life from three to eight years. However
the Deep Soft reserve/resource is limited and at significant risk from seam splitting and
erosive sandstone channels.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 170
OTHER OPERATOR MINES
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.11
HATFIELD COLLIERY
4.11.1
BRIEF DESCRIPTION OF SITE
PAGE 171
Hatfield colliery is located adjacent to the village of Stainforth, South Yorkshire some 11km
north-east of Doncaster, 3km north of the M18 motorway and a similar distance south of the
M62 motorway. The colliery is geographically well placed to supply suitable power station
coal to the local generating stations of Drax, Eggborough and Ferrybridge. It is connected by
main line railway to all of these power stations.
The mine was sunk between 1911 and 1917 to a depth of 800m providing access to both the
High Hazel and Barnsley seams. The High Hazel Seam lies between 580m and 680m below
ground level. The Barnsley seam lies below the surface between 650m and 750m.
The mine site lies on the eastern periphery of Stainforth and has an extensive surface area that
is triangular in shape, inclusive of a large spoil tip. The surface has comprehensive facilities
necessary to support a large deep underground mine. A new coal preparation plant has
recently been constructed; the old facility, which it has replaced, is currently being
demolished.
In 1993 the mine ceased production and was put into ‘care and maintenance’ by British Coal.
Hatfield Coal Company Ltd. re-commenced production at the mine in 1994 under the terms of
a 36 (2a) Licence. This was re-negotiated and changed to a Part 2 Licence inclusive of the
Freehold in 1998.
The mine was planned to produce over 500,000t/a concentrated in the High Hazels Seam,
however, in 2000 due to geological problems, output was restricted to around 400,000 tonnes
and Hatfield Coal Company Ltd applied for, and received Operating Aid. Production
difficulties continued and unfortunately in early August 2001, despite Subsidy, the Company
announced the closure of the mine and the business went into Liquidation.
The Mining License was returned to The Coal Authority who kept the mine on ‘Care and
Maintenance’ whilst a new owner / operator was sought. In the event the License to Mine has
been transferred to a new company Coalpower that has been formed, and is headed by, Mr R J
Budge. On 5th October 2001, Coalpower took over having completed the purchase of the
mine. The mine has since continued production in the High Hazels Seam.
Coalpower intend to develop a “ Power Park” on 33 hectares of the western part of the colliery
site between the main colliery buildings and Stainforth village. The project is planned in two
phases to be completed by 2005/06. The main part of the plan is centred on the construction
of a 430MW Coal Integrated Gasification Combined Cycle (IGCC) Power Generation Plant
which is to be built on an area currently occupied by coal screening facilities.
4.11.2
MINE BOUNDARIES, OTHER SURFACE CONSTRAINTS AND ISSUES
The licence covers an area of approximately 2400 hectares and relates to the High Hazels and
Barnsley seams. High Hazel Seam reserves are contained within an area to the north and east
of the shafts at approximately 650m deep. A much wider licence area covers the Barnsley
seam to the north and east of the shafts at a depth of 750m. Under The Town and Country
Planning Legislation the Colliery is classed as a GDO Mine.
4.11.3
GEOLOGICAL ASSESSMENT OF THE MINE
Hatfield Colliery is situated in the concealed Yorkshire coalfield astride the Morley-Campsall
Fault Belt, a major NW to SE trending structure affecting the Coal Measures in West and
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 172
South Yorkshire. The regional dip of the Coal Measures is towards the east/north east. The
High Hazel Seam, currently being worked, and the Barnsley Seam, some 60m below, lie at
depths of between 600m and 800m.
4.11.3.1
Structure
The licence area is divided geologically by a large fault zone, the Stainforth Fault, that trends
WNW–ESE close to the shafts. This fault zone is part of a major regional system, the
southern boundary of which is a second large fault, which effectively determines the
boundaries of the Hatfield licence area to the south. The overall system is (regionally) a
faulted anticline, and steep bedding dips characterise parts of the licence, although most areas
including the laid-out units are typically gently dipping. A large monocline lies just west of
the present working districts in the northern part of the licence area, and is the effective
western boundary of the resource for present purposes.
Most of the fault data pertinent to the Barnsley Seam are from workings in the overlying High
Hazel. It is noted that the typical thickness of this higher seam is around 1.50m, whereas
typical sections in the Barnsley are 2.00m or greater. Because the mine has a washery capable
of dealing with some excess mined dirt, faults of up to 5m throw have been sometimes mined
through on High Hazel faces.
Regarding the Barnsley Seam in the possible first working area, faults are known through
identification in the High Hazel workings.
4.11.3.2
Seams in Reserves
There are currently two seams shown in the reserve statement for Hatfield Colliery. These
seams are: •
The High Hazels Seam, currently being worked.
•
The Barnsley Seam which is 60m below the High Hazels.
High Hazel Seam Characteristics
On the face that has just finished, F114’ s, the High Hazel Seam was typically 1.55m thick
with two dirt layers in the seam near to the roof. This seam structure section with the dirt
partings near the roof of the seam is typical for the High Hazel seam throughout the worked
area, and is expected to be similar but thinner in section over the area of the planned panels.
These planned panels are expected to have a section around 1.45m at the inbye ends of the
panels to as little as 1.30m along the main laterals.
The roof to the seam is generally mudstone, slightly silty in parts and becoming canneloid
over the current working area. This usually forms a good working roof. The floor measures
are nearly always mudstone seatearth.
For the High Hazel Seam there is an extensive coal quality data set, based on the National
Coal Board (NCB)/British Coal seam sampling programmes from underground locations
(“ pillar samples” ) and from borehole cores. Overall, the data density and scatter are suitable
for building up reasonably robust mapping of the seam variations.
The quality of the High Hazel seam is good in the present area. The expected quality is:
Total seam section
Ash %
Sulphur %
Chlorine %
I5104C
1.3m to 1.5m
5% to 6%
1.3%
0.6%
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 173
This quality is not expected to vary over the remaining areas of the High Hazel that are
planned to be worked.
Barnsley Seam Characteristics
Within the licence boundary, the Barnsley Seam includes all the coalbeds that are developed
regionally across the coalfield, plus local additional coalbeds, above and below. The
following shows the divisions within the full Barnsley Seam. Coalbeds are shown in bold and
splits/significant dirt layers in italics. Dirts are sedimentary layers within a coal seam that are
> 40% ash by weight.
Barnsley Rider (usually coal and inferior coal, with some dirt)
Day Beds/Barnsley Rider split: interval varies
Day Beds (usually clean bright coals)
Middle Beds/Day Beds split: interval varies
Middle Beds (usually clean bright coals)
Warren House/Low Barnsley split: interval varies
Low Barnsley (usually includes clean dull and bright coals with minor dirt: locally
split into two, and sometimes three, main coalbeds)
Dunsil/Barnsley split: interval varies
Dunsil Seam (variable, usually coal with thin dirt)
The Barnsley thickness at Hatfield largely relates to seam splits/unions. The Barnsley Rider
is overlain, in the northern parts of the licenced area, by a channel sandstone/siltstone system
c. 2.5km wide, the details of which require further work for full definition of risk to mining.
However, this channel system is considered unlikely to be involved in washouts of the
underlying Barnsley seam group, but is considered likely to promote local weak immediate
roof, and difficult higher roof character.
The Barnsley Rider/Day Beds split opens south across the Hatfield area, to a likely maximum
thickness of c. 5m. The interval usually comprises mudstone and siltstone seatearths, which
will require careful roof control in zones where the topmost mined coalbed is the Day Beds.
This is the only split that is expected to affect the initial Barnsley mining area.
The Day Beds/Middle Beds split opens rapidly to the south, across the southern part of the
licence area, the interval being occupied by a significant sandstone and siltstone belt. This
latter feature is known in other local deep mines to the southwest, and was associated with
difficult geological conditions, including washouts, across parts of the existing Hatfield mine
workings. Again, however, this split does not affect the initial planned mining area in the
Barnsley Seam.
The Warren House/Low Barnsley split is regionally important, but of only minor significance
at Hatfield, where it is almost everywhere <0.20m thick, and often much less.
The Dunsil/Barnsley split is also known regionally. Where united with the Barnsley, both
seams thicken, and quality attributes are very favourable. This split is mapped south and east
of the initial Barnsley Seam mining area at Hatfield and will not affect this area which is
expected to be Barnsley seam only. Other splits within the Dunsil/Barnsley seam group,
known regionally, are not significant in the Hatfield area.
The floor of the Barnsley varies considerably across the licence area, particularly where the
Dunsil lies close below (in which situation, a very soft working floor may be present).
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 174
Although the above indicates variations in the composition of the seam sections throughout
the licence area, overall the data indicates an attractive mining situation with the seam in the
initial mining area expected to be in the order of 2.65m thick
The boreholes within the first proposed production area indicate that the variations in seam
quality are unlikely to change rapidly. The overall Barnsley Seam at Hatfield shows variation
in its sulphur content, and mined sections in different resource zones will tend to reflect this
varying between 1.7% to 2.5%. Chlorine content of the Barnsley Seam will vary between
0.45% to 0.6%
4.11.3.3
Reserves/Resources Assessment
There is no formal current reserve/resource assessment for Hatfield Colliery. The latest
reserve/resources assessment available to IMC was undertaken in May 2001 for a due
diligence exercise. This reserve assessment dealt mainly with the Barnsley Seam as the due
diligence exercise envisaged the mine accessing this at the earliest opportunity. However as
events overtook the mine, it was forced to look for remnant areas of High Hazel seam to
continue production.
Position with regard to Reserves in 1998
The reserves/resource available at Hatfield in 1998 were as summarised in Table 4-65 below
based on the knowledge at that time.
Table 4-65
Hatfield Reserve/Resource Summary (01/07/98)
(Source: Hatfield Coal Company)
Million Tonnes
Seam
High Hazel
Reserve
Resource
Total
Mineral Potential
1.944
3.827
5.771
2.024
22.227
22.227
26.054
27.998
Barnsley
Total
1.944
2.024
Position with regard to Reserves/Resources in 2001
The summary of the reserves as at May 2001 at the time of the due diligence exercise is
shown in Table 4-66 below. This table quantifies the Barnsley Seam zones based on the
layout in use on 23rd April 2001. No High Hazel seam tonnages were calculated for the due
diligence report, as the seam was, at that time, considered to be virtually exhausted.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table 4-66
PAGE 175
Hatfield Barnsley Seam Reserve/Resource Summary (01/05/01)
Zone
Coal in
mined
section
(cm)
Base
Tonnage
Mt
Mt
(discounted)
Resource *
Meas Ind.
.
Zone 1
191
4.136
3.7
Zone 2
Zone 3
176
158
5.401
6.259
4.9
5.6
4.9
5.6
Zone 4
290
5.189
4.7
4.7
Zone 5
170
1.607
1.0
1.0
Zone 6
191
2.149
0.9
0.9
Zone 7
182
6.247
3.1
3.1
Zone 8
200
10.579
4.2
4.2
Total
-
-
28.1
-
-
3.7
Comments
Variable discounts reflects faults and sandstones in higher
roof; H14’ s is particularly sensitive to faults
Discounts reflect faults and the sandstones in higher roof;
Several units sensitive to faults; Some units sensitive to
seam deterioration and splitting
Thick seam working; units sensitive to local washouts and
faults; increase potential for spontaneous combustion
Units sensitive to faults (much of the zone is first seam
working) the SE portion of each unit is likely to be
unworkable because of seam splitting
Partial extraction area NE of shafts; mined sections as for
Zone 1 above; assume 40% extraction
Section based on Wormley Hill borehole; longwall zone
discounted a nominal 50% for fault uncertainties.
Section based on Picheon Green borehole; longwall zone
discounted a nominal 60% for structural uncertainties and
difficulties associated with sandstones in the higher roof
28.1
Note. * The resource classification adopted here follows that presented in the DTI report of 1999. It should be noted that
Zones 1, 2, 3, 4 and 5 would be classifiable as reserves once contacted by the new drivage.
Each of the zones are commented on below:
Zone 1 has had individual percentage deductions assessed for each face, mostly 5% but rising
to 25% for units which are particularly sensitive to fault uncertainties.
Zones 2 and 4 have been discounted uniformly at 10%.
Zone 3 has been discounted overall at 10%, but with the additional discount of all face 23,
which is considered particularly prone to seam deterioration (increasing ash content of the
coal) and splitting.
Zone 5 has been discounted 40%, to reflect fault uncertainties and of gross seam deterioration
and splitting to the south-east.
Zones 6, 7, and 8 have been assessed on a gross area and discounted by a nominal 50%.
A plan is included showing the reserve zones based on the layout provided in May 2001
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Figure 4-21
PAGE 176
Hatfield Colliery Barnsley Seam Resource Zones May 2001
HUSHELLS
LANE BH
Est. Se am 685m BOD
ZONE 7
NEW HOUSE LANE BH
Est. Seam668mBOD
6
WESTFIELD LANE BH
Est. Seam627mBOD
10
11
ZONE 2
9
8
7
FOSTERHOUSES BH
Seam 264 (687m BOD)
Coal 215
Cover 692m
4
5
MILLFIELD
ROAD BH
Est. Seam 661m BOD
WOODHOUSE
GREEN BH
BARNSLEY SEAM
646m BOD APPROX.
CARR HEAD LANE BH
Est. Seam 711m BOD
WORMLEY HILL BH
Seam 248 (691mBOD)
Coal 206
Cover 694m
H2
11A
SNELSHOLME LANE BH
Est. Seam697mBOD
H3
H1
ZONE 1
Le
ve
l?
PLUMTREE HILL BH
BARNSLEY SEAM
663m BOD APPROX.
12
HAYES LANE BH
Est. Seam 688m BOD
13
ZONE 6
H1A
FISHLAKE NAB BH
WOOD LANE BH
Seam 285 (694m)
Coal 228
Cover 697m
14
SOUR
LANE BH
TOWN ING BH
Est. Seam688mBOD
RAMSKIN
LANE BH
627.0
TOWN ING
ROAD BH
Est. Seam688mBOD
U/G BH
No.36
Seam688.4mBOD
15
17
Seam 714.1m BOD
U/G BH
No.14
16
18
26
25
19
ZONE 3
20
Seam 763.6m BOD
U/G BH
No.35
28
21
27
U/G BH
No.15 &15A
Seam 728.4m BOD
22
ZONE 4
30
23
29
U/G BH
No.45 & 45A
Seam 727.3m BOD
24
U/G BH
No.63 &63A &63B
Seam764.6mBOD
U/G BH
No.52 & 52A
Seam 731m BOD
U/G BH
No.65
Seam 746.7m BOD
33
32
31
ZONE 5
DALE MOUNT FARMBOREHOLE
Est. Seam738mBOD
GROVE HOUSE BOREHOLE
Seam 767m BOD
THE SEVERALS BOREHOLE
Est. Seam758mBOD
U/G BH No.64
Seam710.5mBOD
(Top Softs)
Changes between Reserve Assessments
Since 1998 the High Hazel tonnage has reduced dramatically. Mining difficulties have meant
that the operator is unlikely to access large areas of what were termed resources and mineral
potential in 1998. These blocks of coal, particularly those in the south of the mine and to the
north and west of the present workings are for the main part abandoned and are not now
included in the assessment. This accounts for some 2.8Mt of resources and 2.0Mt of mineral
potential that have been deleted from the new assessment.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 177
Of the remaining reserves and resources, faulting has reduced some of the panel lengths and
necessitated a reappraisal of the panel layouts to allow production to continue and has forced
the colliery to plan on accessing areas of coal that were not in the 1998 assessment. Working
of the seam has also accounted for the remainder of the tonnage change.
No assessment of the High Hazel Seam was undertaken in 2001 and no formal assessment is
available for 2002.
A similar case exists for the Barnsley Seam: no formal 2002 assessment has been done and
therefore the only comparison that can really be made is that of the Barnsley Seam in 1998
with that same seam assessment in 2001. This shows that, after detailed mapping of the
Barnsley Seam, the indicated resource increased from 22.2Mt to 28.1Mt based on the realistic
layouts available in 2001.
4.11.3.4
Exploration
As far as can be ascertained, no exploration is planned at Hatfield in the near future.
4.11.3.5
Other Seams of Interest
There are no other seams of interest at Hatfield
4.11.3.6
Geological and Reserve/Resource Conclusions for Hatfield Colliery
The main conclusion from examination of the remaining blocks at Hatfield in the High Hazel
is that the Colliery is at high risk of losing some of its present reserves and resources because
of faults. The mine has also, with its present plan, lost access to a large resource block in the
north west of the mine in this seam. This is largely due to the advancing face, F124’ s, (from
which access was to be made in the 1998 plan), encountering a very large 45m upthrow fault.
However, the Colliery does have a very large resource in the Barnsley Seam that is of greater
thickness and much lower geological risk than the present working seam.
I5104C
IMC GROUP CONSULTING LIMITED
468 KmE
467 KmE
466 KmE
465 KmE
464 KmE
463 KmE
462 KmE
SOUTHFIELD
RESERVOIR
BEEVERS BRIDGE BH
ER NAVIGATION
AIRE AND CALD
NORTH
SEQUENCE OF SEAMS
Seam
Code Section Depth
Shafton
A
0.5
402
Sharleston Top
BT
0.2
447
Houghton Thin
0.7
503
Wheatworth
0.8
540
Swinton Pottery
Newhill
418 KmN
Meltonfield
Two Foot
Winter
0.5
564
C
0.9
581
D
1.0
599
DD
0.5
607
E
0.4
612
High Hazel
F
1.4
634
Kents Thick
G
0.8
665
Barnsley
H
2.8
703
Dunsil
J
0.7
720
Flockton Thick
P
1.6
820
Fenton
R
0.5
844
Parkgate
T
1.3
854
Thorncliffe
V
0.7
874
Blocking
X
0.9
899
Top Beeston
Y
1.4
926
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
I5104C
419 KmN
Interval
RIVER WENT
45
56
37
24
17
18
8
5
22
31
38
17
100
24
10
20
25
PINCHEON GREEN BH
Seam 147 (677m BOD)
Coal 143
Cover 685m
27
Details are averages from the
surface boreholes shown on this plan.
30.0
417 KmN
VE
R
DO
WORMLEY HILL BH
Seam 146 (628m BOD)
Coal 146
Cover 632m
N
ASH HILL BH
Seam 107
Coal 91
RI
Inferior co
in top 30-40al develops
cm of seam
THORNE COLLIERY
HIGH HAZEL SEAM
WORKINGS
<10.0
?
?
416 KmN
?
F125
F114
BELL GREEN BH
Est. Seam 634m BOD
2.4
<10.0
Figure 4-22
U/G BH No.75
2.0
F124
F123
0.2
0.4
0.7
130-140cm
0.6
F114
F122
F127
0.6
U/G BH No.71
0.9
0.3
0.4
0.9
0.3
0.3
0.7
1.6
1.7
0.2 1.2 1.0
0.5
2.5 0.8
0.3 3.5
2.3
3.0
Y
ILLE
SW
0.1
6
No.7
BH
HUSHELLS
LANE BH
170
0.1
0.6
0.1
0.4
1.4
0.2
F112
0.7
FOSTERHOUSES BH
Seam 140
Coal 133
F121
2.0
1.6
6.5
F120
0.3
1.8
F118
HAYES LANE BH
Est. Seam 618m BOD
140
150
1.3
170
160-170cm
120-140cm
0.2
0.4
0.5
>4.5
0.5
0.2
9.7
16.0
0.8
1.1 0.6
0.3
0.9
0.7
1.0
1.4
0.8
0.4
1.1
O
TOWN ING
ROAD BH
0.9 3.7
2.1
14.3
F102
0.6
57
SOUR
LANE BH
0.4
0.6 1.0 0.4
0.6
14.3
1.2
3.7
7
No.6
BH
U/G
0.6
0.9
FISHLAKE NAB BH
0.5
F101
0.3
90
9.7
>4.0
0.1
0.3
T
No.69
0.6
0.2
2.1
O
U/G BH
80cm
170-1 F103
180
Junction 6
2.1
R
cm
-180
170
180
TOWN ING BH
Est. Seam 618m BOD
0.3
1.3
0.3
F104
Y
MILLFIELD
ROAD BH
F105
A
1.6
0.7
1.8
0.2
0.4
W
140-150cm
U/G
BH No
.74
WESTFIELD LANE BH
Est. Seam 557m BOD
2.3
0.2
0.7
0.4 4.6
0.3
414 KmN
3.0
0.4
0.5
1.0
0.5
0.2
M
180
F110
0.1
F107
413 KmN
0.4
0.2
18
NE
W
0.1
WOOD LANE BH
Seam 143 (628m)
Coal 141.5
Cover 631m
140
Y
LE
IL
SW
Est. Seam 598m BOD
WOODHOUSE GREEN BH
SNELSHOLME LANE BH
Est. Seam 627m BOD
F111
0.1
NEW HOUSE LANE BH
WOOD END BH
Seam 155 (428m BOD)
Coal 126
Cover 434m
1.0
1.0
U/G BH
No.72
0.7
2.0
1.7
0.2
M
CA
NA
L
0.6
.77
No
BH
0.1
SMALLHEDGE ROAD BH
Est. Seam 512m BOD
0
16
16.0
2.0
0.5
1.8
0.3 0.8
0.1
RI
R
VE
DO
U/G BH No.36
Seam 615.4m BOD
N
150
0.2
0.5
0.9
0.2
0.9
1.2
8.8
3.5
13.7
0.8
0.8
0.4
60
0.7
412 KmN
3.0
1.2
U/G BH No.61
ATION
RIVER DUN NAVIG
1.1
0.5
0.9
2.7
0.3
0.5
0.3
0.3
0.5
0.3
0.9
0.3
0.1
2.7
0.1
0.3
0.5
0.6
0.3
0.3
0.3
U/G BH No.14
1.2
31.1
90.0
6.1
0.2
ZER
O
0.1
0.1
ZER
O
2.0
9.1
23.2
0.8
0.3
2
0.2
0.6
0.8
0.3
9.8
0.4
RACK
0.5
2.3
1.2
1.5
4.6
0.2
0.6
RAILT
2.6
19.8
0.4
0.7
1.1
0.8
0.8
0.3
0.4
0.7
1.0
19.8
U/G BH No.62
0.3
0.1
0.3
0.1
0.3
0.3
4.9
0.9
1.2
1.8
0.6
0.5
0.3
0.5
0.3
59
RAMSKIN
LANE BH
0.2
0.2
0.4
N
TIO
IGA
AV
E N AL
HIR CAN
KS
OR ADBY
Y
TH & KE
OU
& S RTH
LD INFO
FIE
EF STA
SH
PLUMTREE HILL BH
SWILL
EY
Hatfield Colliery: High Hazel Seam Plan
JU
NC
TIO
N
2.0
1.0
0.2
U/G
0.1
0.2
4.7 0.4
12.2
CARR HEAD LANE BH
Est. Seam 641m BOD
1.9
0.3
5.0
0.5 1.5
2.5
1.0
2.1
1.4
0.2
4.8
2.1
4.6
4.8
0.6
1.3
0.3 0.7
0.9
1.4
1.8
2.1
1.4
1.4 0.71.10.9
0.2
1.2
1.0
BH
No
.78
E
U/G
0.2
0.3
160
415 KmN
150
Major Mo
High Ha nocline - Stee
west limzel Seam 20 p Gradients.
0m
it of po
ssible wohigher to
rkings.
U/G
3.9
CK
RA
ILT
RA
0.1
0.6
1.2
0.5 0.2
0.5
0.6
0.4
21.3
15.2
0.4
1.4
0.6 0.7
0.9
3.4
0.6
0.6
2.2 0.9
0.2 1.2
0.8
0.5
1.8
0.4
0.9
1.1 0.3 1.2
3.6
40.0
18.0
18.6
0.8
0.3
1.1
1.5 0.6
0.8
0.2
0.3 0.6
1.2
7.0
0.3
0.4
1.0
30.5
0.3
58.0
56.0 0.4
0.8
U/G BH No.58
0.9
2.1
3.4
1.5
1
0.6
1.3
0.3
411 KmN
0.3
0.2
0.3
90.0
Junction 5
U/G BH No.15 &15A
Seam 642.2m BOD
76.2
29
0.6
U/G BH No.35
Seam 673.3m BOD
0.6
30
0.3
0.9 0.3
0.8
462 KmE
0.2
0.6
1.5
0.9
0.4
0.7
H
ITIS
BR
0.2
IL
RA
U/G BH Nos.51,51A
18.3
U/G BH No.55
0.2
0.5
0.5 1.3
0.6
0.9
1.8
0.8
0.5
0.8
410 KmN
0.6
1.2
0.9
0.3
0.5
0.3
2.6
0.5
FINANCIAL YEAR
1st January to 31st December.
TYPICAL SEAM SECTION
Fosterhouses Borehole
(F121’s Area)
REFERENCE
Seam Deterioration
2003
2004
2005
2006
Seam Thickness cm.
(Isopachyte)
Barnsley Seam Workings
150
SEAM CONTOURS IN METRES
BELOW ORDNANCE DATUM
Dirt 4
Dirt 4
CURRENT SEAM SECTION
F114’s Unit
TYPICAL SEAM SECTION
Wormley Hill Borehole
Mudstone
Mudstone
Canneloid Mudstone 25
Coal 17
Coal 10
Coal 9
Dirt 9
Dirt 4
0.3
1.8 1.2
0.6
2.5
0.5
1.9
0.6 0.9 1.2
2.4 1.5
0.3
U/G BH No.54 0.7
U/G BH No 4?
0.2
0.5
Mudstone
Coal 13
Coal 105
Coal 120
Coal 146
Mudstone
Seatearth
Mudstone
Seatearth
Mudstone
Seatearth
0.9
1.8
1.0
15.2
0.3
29.3
1.5
4.3
33.5
COAL POWER LIMITED
HATFIELD COLLIERY
HIGH HAZEL SEAM
RESERVES PLAN
PAGE 178
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
Scale: 1/10,000
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Coal 92
Km
N
47
3
Km
E
OIL
PIP
EL
INE
47
3
Km
E
Coal 41
Dirt 5
Coal 27
RI
VE
Coal 33
Dirt 9
R
DO
Inf.Coal 8
Dirt 11
Rider
66
N
Coal 47
Dirt 147
Coal 69
Seam
147
RIDER
COAL
SPLIT
Dirt 10
Coal 38
PINCHEON GREEN BH
Seam 751.5m BOD
Dirt 3
Coal 64
47
2
Coal 37
U/G BH
No.45 & 45A
Seam 727.3m BOD
Dirt 7
Inf.Coal 7
Dirt 21
2.1
Coal 103
Dirt 5
WOOD LANE BH
Seam 285 (694m)
Coal 228
Cover 697m
<10.0
Coal 51
Dirt 2
Coal 33
6
Ju
nc
tio
n
Km
N
41
7
OTO
M18 M
3.0
1.0
43.0
PIPE
LINE
RWAY
SNELSHOLME LANE BH
Est. Seam 697m BOD
Km
E
2.6
3.2
<10.0
W/E(S
) & M/
R OIL
ST
N TO EA
ERIORATIO
SEAM DET
Total
Seam
285
30.0
CARR HEAD LANE BH
Est. Seam 711m BOD
Coal 55
Inf.Coal 7
Dirt 12
10.0
2.3
GROVE HOUSE BOREHOLE
Seam 767m BOD
Inf Coal 16
Dirt 10
0.8
WORMLEY HILL BH
Seam 248 (691m BOD)
Coal 206
Cover 694m
Km
N
Dirt 18
41
8
Km
N
Total
Seam
305
41
0
H
AT
FI
E
LD
Inf.Coal 5
Dirt 14
Km
E
46
4
ARY
ND
OU
EB
NC
ICE
L
E
RN
THO
Km
E
41
2
41
3
Km
N
41
4
M/R
Coal 109
46
5
47
2
The faulting shown on this plan
have been determined by either
projection from the High Hazel
Seam or from surface seismic
interpretation.
Coal 7
Dirt 18
Coal 31
Dirt 5
Coal 4 (inf)
Dirt 6
Total
Seam
248
Km
E
Km
N
Km
N
41
5
Km
N
41
6
Km
N
47
1
Km
N
B
O
U
N
D
A
R
Y
Km
E
BO
UN
DA
RY
COURT ORDER AREA
Dated 17.9.34
Not to be Worked
Without Consent
LI
C
E
N
C
E
47
0
W/E
(S)
&
S
E
A
M
W
EN
T
Km
E
Dirt 12
B
A
R
N
S
LE
Y
RIV
ER
46
9
41
1
BEEVERS BRIDGE BH
Km
E
LI
CE
NC
E
Km
E
41
7
41
8
TH
O
RN
E
NOR
TH
41
9
46
6
46
8
Km
N
Km
E
Km
N
46
7
PAGE 179
Km
E
U/G BH
No.52 & 52A
Seam 731m BOD
TOWN ING BH
Est. Seam 688m BOD
DALE MOUNT FARM BOREHOLE
Est. Seam 738m BOD
47
1
4.1
Km
E
Y
SLE
RN
BA
THE SEVERALS BOREHOLE
Est. Seam 758m BOD
2.1
HAYES LANE BH
Est. Seam 688m BOD
1.3
1.4
Dirt 7
13.7
U/G BH
No.36
Seam 688.4m BOD
0.3
540
0.5
564
Swinton Pottery
Newhill
C
0.9
581
Meltonfield
D
1.0
599
Two Foot
DD
0.5
607
E
0.4
612
High Hazel
F
1.4
634
Kents Thick
G
0.8
665
Barnsley
H
2.8
703
Winter
Dunsil
J
0.7
720
Flockton Thick
P
1.6
820
Fenton
R
0.5
844
Parkgate
T
1.3
854
Thorncliffe
V
0.7
874
X
0.9
899
Top Beeston
Y
1.4
926
Details are averages from the
surface boreholes shown on this plan.
56
37
24
17
18
8
5
22
31
38
17
100
24
10
20
25
27
9.7
1.8
16.0
2.8
4.6
0.8
6.1
1.1
1.4
710
710
4.9
1.2
1.5
2.0
WESTFIELD LANE BH
Est. Seam 627m BOD
705
19.8
3.0
1.0
2.6
RAMSKIN
LANE BH
>4.5
4.3
1.5
1.2
3.2
PLUMTREE HILL BH
BARNSLEY SEAM
663m BOD APPROX.
>4.0
3.0
1.1
46
4
Km
E
M
EA RY
Y S DA
LE OUN
S
RN B
BA NCE
E
90.0
LIC
1.8
2.7
7.3
1.5
3.7 1.2
1.2
1.0 6.7
3.6 3.3
1
0.9
1.8
1.8
0.4 0.6
1.0 1.8
0.6
89.6
5.5
0.6
I5104C
Km
N
40
9
Km
E
2.0
715
0.6
30.4
15.2
0
76
710
18.3
0.9
1.2
0.7
1.4
0.4
715
0.9
0.8
5.2
1.4
1.8
1.0
8.8
4.6
0.8
1.2
710
2.4
715
1.4 0.8
0.8
0.6
720
46
6
0.6
0
73
Km
E
740
Coal 104
0
71
0.6
0.9
5
72
Dirt 14
Coal 47
Dirt 4
Coal 32
Figure 4-23
46
9
2.1
2.6
0.9
725
Total
Seam
265
SEAM CONTOURS IN METRES
BELOW ORDNANCE DATUM
40.0
720
5
0.6 78
780
5
77
2.1 0.9 70 0.6
7 5 0.9
6
7
1.8
0
76
5
7550
7 45
7
0
74 5
73 0
0.8
73
0.9
Seam Splits
High Hazel Seam Workings
8.2
725
Inf.Coal 14
Coal 33
Dirt 7
Barnsley Seam Workings
4.3
33.5
REFERENCE
Faulting
7.0?
3.4
720
5
E
50.0?
2
76
U/G BH
No.63 & 63A &63B
Seam 764.6m BOD
U/G BH
No.35
Seam 763.6m BOD
5.2
700
9.8
WOODHOUSE
GREEN BH
BARNSLEY SEAM
646m BOD APPROX.
Km
U/G BH
No.65
Seam 746.7m BOD
1.8
705
3.2
47
0
2.2
0.8
1.0
6.0?
SP
LIT
Coal 79
0.8
19.8
BA
RN
SL
EY
U/G BH No.64
Seam 710.5m BOD
(Top Softs)
3.4
18.6
LO
W
ER
0
72
715
Blocking
45
Km
N
503
0.8
41
2
447
0.7
Km
N
0.2
Wheatworth
1.7
Dunsil
Seam
158
U/G BH
No.14
Seam 714.1m BOD
FISHLAKE NAB BH
41
3
BT
Houghton Thin
AL
CAN
Sharleston Top
Interval
ON
CTI
JUN
402
NEW
0.5
Km
N
A
41
4
Code Section Depth
RY
DA
UN
BO
CE
EN
LIC
AM
SE
EY
SL
RN
BA
Seam
Shafton
2.0
Coal 40
Dirt 3
Coal & Dirt 13
Dirt 23
10.7
AN
D
Km
N
NEW HOUSE LANE BH
Est. Seam 668m BOD
2.6
Coal 41
5
0.8
MILLFIELD
ROAD BH
Est. Seam 661m BOD
Dirt 37
1.4
0.9
SE
PA
RA
TIO
N
Dirt 5
2.7
1.0
SMALLHEDGE ROAD BH
Est. Seam 582 BOD
0.6
SE
AM
Coal 107
Km
N
Dirt 4
Coal 32
Coal 97
SEQUENCE OF SEAMS
1.1
14.3
Coal 47
OF
F
Dirt 13
1.4
Dirt 14
UP
PE
RP
AR
TD
AY
BE
DS
SP
LIT
Km
E
Total
Seam
265
5.0
Dirt 3
Total
Seam
323
N
ATIO
AR
EP
58.0
MS
EA
IL S
S
N
/DU
EY
SL
RN
BA
40.0
0.9
2.5
Dirt 39
Coal 79
0.9
RAILTRA
CK
46
3
Coal 103
Total
Seam
297
Coal 98
SH
EF
FIE
L
ST D &
AIN SO
RI
VE
FO UT
R
RT H Y
DO
H OR
N
&
KE KS
AD HIR
BY E
CA NAV
NA IG
L ATIO
N
41
6
Km
N
Dirt 28
Coal 3
Dirt 3
3.5
Dirt 4
3.7
ts.
ien
ad to
Gr er .
ep igh gs
Ste m h rkin
e - 200 wo
le
clin m
no ea ssib
Mo y S f po
jor sle it o
Ma Barn t lim
s
we
Coal 3
Dirt 3
Coal 46
SOUR
LANE BH
1.1
Coal 104
BA
RN
SL
EY
/D
UN
SIL
Coal 23
8.8
Coal 93
Ju
nc
tio
n
HUSHELLS
LANE BH
Est. Seam 685m BOD
BELL GREEN BH
Est. Seam 704m BOD
TOWN ING
ROAD BH
Est. Seam 688m BOD
Total
Seam
282
40
8
1.6
40
9
1.8
RA
ILTR
AC
K
Coal 33
705
15.2?
6.5
71
0
Inf.Coal 14
RY
DA
UN
BO
CE
EN
LIC
AM
SE
Dirt 18
Coal 6
Dirt 34
1.6
FOSTERHOUSES BH
Seam 264 (687m BOD)
Coal 215
Cover 692m
90.0
U/G BH
No.15 &15A
Seam 728.4m BOD
Coal 28
715
COAL POWER LIMITED
HATFIELD COLLIERY
BARNSLEY SEAM
GEOLOGY AND SEAM STRUCTURE
Scale: 1/10,000
Hatfield Colliery: Barnsley Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.11.3.7
PAGE 180
IMC Commentary on the Reserves/Resources at Hatfield Colliery
Hatfield Colliery is in the position where the strategy necessitates staying in the High Hazel
Seam where faces are planned in very high risk areas from both a mining and geological point
of view. To reflect this, the reserve/resource in this seam is shown below based only on the
planned layout in the High Hazel.
The Barnsley Seam reserves/resources are based on the plan provided by the colliery on the
possible access to that seam. This is similar to plans devised in the due diligence exercise for
the colliery but with slight variations in the access to the seam.
The following table outlines the reserves/resources as defined by IMC at the mine as at
December 2002.
Table 4-67
Hatfield Reserve/Resource Summary (16/12/02)
Million Tonnes
Seam
Reserve
Resource
Total
0.675
0.961
1.636
Barnsley (Part Zone 1)
0
2.25
2.25
Barnsley (Remaining Zone 1)
0
1.45
1.45
Barnsley (Zone 2)
0
4.83
4.83
Barnsley (Zones 3 to 8)
0
0
0
19.50
0.675
9.491
10.166
19.50
High Hazel
Total
Mineral
Potential
Comments on the reserve/resources at the colliery are given below:
High Hazel Seam
The High Hazel tonnages in the area shown on the plan are all at high risk from mining and
geological factors. The seam sections are well known. However there is, on each of the
planned faces, a high risk of faulting and for this reason two of the planned panels F127’ s and
F118’ s are assessed as resources until proved.
The tonnages calculated on these panels have been relaxed by 25% for F118’ s and 30% for
F127’ s. These reductions are for: 1. F118’ s
a known fault of seam thickness throw that will be present on the face at the
finish of the panel, and for faulting inbye encroaching onto the right hand gate.
2. F127’ s
The presumed direction of a 6m to 10m throw fault seen in the main lateral
roadways and shown on the plan as being off the left hand gate of the face. This fault was
proved by in-seam drilling from the adjacent face but its direction for 70% of the panel
length is uncertain.
Both these panels will also be affected by a swilley that crosses the adjacent faces.
The other two panels, F123’ s (already headed out and with known faulting on the panel) and
F125’ s adjacent to the advancing panel that has just finished, are deemed to be in reserves due
to the lower geological risk. However there is still a mining risk to these panels and the
reserves have been reduced by 5% to allow for this.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 181
Barnsley Seam
The Barnsley Seam, Zones 1 and 2, are assessed, as in 2001, as a resource and the comments
made in 2001 shown in Table 4-66 are still valid. The 2002 tonnages use the same deductions
for geology as applied in 2001 and the same geological criteria.
The only difference is that there is a planning change in the number and widths of panels
shown on the mining plan. This has necessitated a slight recalculation for the resources
shown in the 2002 assessment, especially for Zone 1 where the present plan shows only part
of this zone being accessed and worked. The remaining tonnage in this zone is shown as a
resource even though there are no planned panels for the remaining area.
It should be noted that the geological risk to these two zones from faulting is very low as the
majority of the panels are shown lying beneath worked High Hazel Seam and have been
planned in such a way to avoid the known faulting. There is still some sedimentary risk to
these panels but this is accounted for in the deductions made on the tonnages.
The rest of zones 3 to 8 remain unchanged as far as the tonnage calculations are concerned but
have been assessed as mineral potential for the present. This is because the access to these
remaining zones will necessitate further drivages that are different to those used to access
Zones 1 and 2.
In the strict terms of the reserve assessment criteria this tonnage could be assessed as
Indicated Resource but until plans to access these blocks of coal are in place they should
realistically be regarded as Mineral Potential.
From the above, taking into account the risk to the High Hazel panels, any future for the
colliery lies in the Barnsley Seam. In this seam there should be a relatively low geological
risk to any of the planned panels although interaction with the High Hazel above will cause
some problems.
It should also be noted that Hatfield Colliery lies adjacent to it the Thorne Colliery licence.
This mine’ s resources can only be accessed either by re-opening Thorne Colliery or by
development from Hatfield into the adjacent resource blocks.
4.11.4
MINE CHARACTERISTICS AND CONSTRAINTS
The mine presently operates in the High Hazel Seam, which essentially is close to being
exhausted. The reserves lie in areas where the frequencies and directions of faults are
uncertain. These areas also lie distinct from the present infrastructure and may prove difficult
and costly to access.
Since the thickness of the High Hazel Seam is only about 1.35m in the present working area,
production from longwall retreat faces is limited. Over the past few years annual outputs from
the mine have not exceeded 500,000 tonnes. In 2003 Coalpower Limited (CPL) have planned
to produce 600,000 tonnes for the year from two retreat faces. Whilst CPL have moved from
advance to retreat longwall production and therefore achieved a more favourable position,
their long-term prospects may present problems. Faces that are planned after 2003 are located
in remnant pieces of coal. These areas have been left between previously worked faces. Their
geology has uncertainties and the panel layouts will be difficult relative to high stress
abutments left by the old workings. Accepting the progress that has recently been achieved
IMC is of the opinion that the options left in this seam are both risky and unlikely to achieve
any sustained success in the long-term. Nevertheless, with sufficient financial resources,
Hatfield does have potential prospects in the Barnsley Seam some 70m below the High Hazel
seam.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 182
Although, not yet accessed, extensive areas of coal have already been identified in the
Barnsley seam. Since significant parts of the Barnsley are in the shadow of the High Hazel
workings most fault structures are reasonably well defined. Whilst sulphur content of the
seam is relatively high, overall quality should meet the specifications required by the local
power stations. The two access tunnels chosen to contact the Barnsley seam by CPL appear
both direct and related to the present High Hazel infrastructure. Steeper gradients have been
planned for the access roadways as a matter of expediency. This will minimise the lengths of
expensive rock drivage and reduce the time of completion to more acceptable phasing. The
area to be accessed is zones 1 and 2 (refer Figure 4-23). It is estimated that there is potential
for 8-years production at a rate of 1.5Mt/a in this area. CPL has outline plans showing
additional access drivages from the High Hazel seam into the Barnsley seam. These drivages
are located further outbye, towards Hatfield shafts, and having accessed the Barnsley Seam
are then driven in-seam into extensive areas of coal presently contained within Thorne licence
boundary. Whilst plans are being developed for both short and long term access to the
Barnsley Seam, CPL are faced with a problem of raising sufficient capital investment to
support these major projects. Since prospects from the High Hazel Seam are at best extremely
limited as a source of funds CPL will be faced with the difficulties of raising external finance.
This may prove too onerous a task due to the general marketing weakness that is affecting the
rest of UK deep mines.
At present coal is conveyed from the High Hazel face and developments into two strata
bunkers. The latter have a combined design capacity of some 2500 tonnes of mineral. Both
bunkers outfeed on to a trunk conveyor at the lower Barnsley Horizon and from there to the
No.1 shaft. Coal is then wound up to the surface in 10 tonne capacity skips. The mine is
reported to have sufficient winding capacity to support an annual output of 1.3Mt saleable.
It is worth noting that sections of the lower Barnsley Seam roadways in the Pit Bottom area
are in places extremely limited in cross-section. CPL recognises these problems and are
planning extensive repairs in the future.
The mine operates with a locomotive system of transport for manriding and materials through
the main return roadways. At the inbye section of the mine materials are transferred to rubber
tyred vehicles (FSV’ s). All of these vehicles have been used for a number of years and most
are expected to be replaced within the next five years.
Hatfield has operated with two sets of face equipment and a single production face. The
machines used for development drivages are limited and this has been recognised by CPL.
Replacement machines are planned for future drivages.
Since privatisation the mine has not generated sufficient cash or attracted capital to maintain a
continuous improvement programme in most of the operations within the mine. Finally, if
there is a future for the mine then it must be in the Barnsley Seam.
4.11.4.1
Ventilation
The present main mine fans are capable of ventilating the mine for the near future. Main fan
duty is 180-186m3/sec at static pressures between 3.5 and 4.2kPa. There are at present
constraints to airflow on the intake side and return side to the High Hazel workings.
The present ventilation model is based on a ventilation pressure/quantity survey carried out
some five years ago and there is some doubt on the accuracy of the data. There is a
requirement to conduct a further pressure/quantity survey and produce a ventilation plan for
the mine.
The propensity for coal to develop ‘self-heating’ or spontaneous combustion depends on
many physical factors including (i) the nature of the coal; (ii) the ventilation airflow and (iii)
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 183
the method of production. Of these, the nature of the coal is the most significant factor. The
High Hazel Seam is classed as medium risk; even so there has been a reported incident in
F107’ s unit at the mine. The Barnsley Seam is classed as high risk from spontaneous
combustion and there is at least one incident per year in the Yorkshire Coalfield.
The mine has an installed ‘tube bundle’ system to collect gas samples from known points
underground and to transport them to the surface for analysis. This system uses a 30-year old
technology and the tube bundle diameter is such that there are long delay times between
sampling and analysis (+1hour). The system is being maintained by TES Bretby (the original
designers and constructors) but they have a limited amount of spare parts – if the system fails,
it may not be repairable. An updated system should be installed prior to entry into the
Barnsley Seam.
The mine should also install fixed-point electronic monitors, which will give virtually
instantaneous readings of the underground environment, including the level of carbon
monoxide.
There is a minor problem with hydrogen sulphide at the pumping station close to the No.2 pit
bottom on the High Hazel horizon. This pumping station is hand monitored and is so fenced
that ‘no unauthorised personnel’ can gain access. As such, this is considered safe.
The Barnsley Seam in-situ methane gas content in the area of Hatfield Colliery is
approximately 4.5m3/tonne. A sample taken from the Barnsley seam in the nearby Markham
Colliery in 1998 showed a gas content of 4.3 m3/tonne. The working of the High Hazel seam
some 70m above the Barnsley Seam will have partially de-gassed potential gas horizons
above the Barnsley seam, and the Barnsley seam itself. Hence, the estimated future gas
emissions from the planned faces within the Barnsley seam are considered average and as
such, controllable.
A localised methane drainage system has been utilised in the High Hazels Seam. The pressure
applied to the gas drainage reticulation system is provided by tank mounted Nash L6 vacuum
pumps. The manufacturer no longer produces these, but spares should be available for the
short/medium term. An improved system needs to be considered prior to any workings in the
Barnsley Seam.
The face design at the return end needs to be considered to allow methane drainage to be
practised. A Back-airway or Sherwood curtain system will need to be implemented, without
which methane migration at the return end could be a potential problem.
4.11.4.2
Subsidence
High Hazels Seam
Panel F125: F125’ s will underwork a low-lying area, which is only some 4m above sea
level. Drainage is the main consideration for this panel. Subsidence damage costs could be in
the order of £1.50/t.
Panel F123: This panel will also work beneath low-lying land and affect some properties at
Fosterhouses Village. Subsidence damage costs are estimated at £1.50/t.
Panel F127: F127’ s will also affect properties in Fosterhouses Village and will work within
the influencing distance to the River Don. Subsidence damage costs are estimated to be
£1.50/t.
Panel F118: This panel will affect both the River Don and Fishlake village. Subsidence
damage costs are estimated to be £1.50/t.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 184
Barnsley Seam
A number of panels have been planned for this seam under working in the area of land
between the River Don and the New Junction Canal. A few villages will be affected but the
greatest concern is for land drainage. Subsidence damage costs are high and estimated around
£2/t.
4.11.4.3
Coal Preparation Facilities
The present plant at Hatfield is rated at 550t/h, consisting of a Large Coal Washing Section,
Small Coal Washing Section, Dry Fines Extraction and a water clarification circuit. The unit
was commissioned during 2002. If required, the plant should have a potential capacity of
55,000t/w equating to 2.64Mt/a of ROM.
ROM from the shaft is size controlled with a “ MMD” coal sizer to 150mm top size, this is the
put to ground stock. Recovery of the ROM is by mobile plant feeding a static grizzly over a
feed hopper. The hopper is fitted with a variable speed weigh feeder thus controlling the plant
feed rate. The feed passes over an inclined screen, the first section of which extracts a dry
fines, the second section of screen removes a further portion of fines that are flushed to the
barrel dewatering/classifying screen under-pan. Screen oversize is then fed to the Natural
Medium Barrel. This separation produces a clean coal and discard, the discard having been
dewatered is put to ground for disposal on the tip. The clean coal is dewatered and screened;
the oversize is reprocessed in a Large Coal DM Drum, while the undersize is processed in a
set of primary NM Cyclones.
The DM Drum rewashes the oversize fraction of clean product from the barrel, providing a
suitable quality fuel for the domestic market. This product is put to stock and classified using
mobile plant when despatched. The Discard from the DM Drum is crushed an added to the
PSF blend.
The cleaned coal recovered by the primary NM Cyclones is dewatered and blended with the
dry fines to make the PSF blend. The primary discard is then fed to a pair of secondary NM
Cyclones. With current conditions this is re-washing the discard, but can, if required recover a
middlings product should the need arise in the future. At this time the product is out-loaded
with the primary product; facilities are available for this to be out-loaded as a separate product
to be added to the PSF blend. This system allows for a cleaned washed smalls to be outloaded as a separate product should the need occur.
The washing media is controlled, with a partial bleed to a water clarification plant. The
medium bleed is fed to a “ Parnaby Clarifier” , separating solids from liquid with the aid of a
flocculent. The recovered top water is re-used within the washing process, the recovered
sludge is dewatered on a Multi Roll Filter, the resulting cake is layered into the tipping
process by mobile plant.
Current conditions are producing 65 to 70% vend, all of which is destined for the power
generation market. The plant is flexible, and there are provisions to add further fines treatment
should the need arise.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.11.5
PAGE 185
HISTORIC PERFORMANCE
4.11.5.1
Production
Table 4-68
Historical Production Performance at Hatfield
Hatfield
1999
2000
2001
2002
(10 months)
Actual Output
million tonnes – saleable
0.460
0.397
0.173
0.299
Budgeted Output
million tonnes - saleable
0.522
0.407
0.450
0.431
Difference
million tonnes - saleable
-0.062
-0.010
-0.277
-0.132
Production throughout the period has suffered from uncertain geology within the High Hazels
seam. The previous operators, Hatfield Coal Company Ltd, operated a single advance face.
Output in the first quarter of 2001 continued to be depressed as the face in operation (F114’ s)
was turned some 400 away from geologically disturbed ground (monocline with steep
gradients) to an orientation parallel to the New Junction Canal along which the Licence
Boundary runs. In early August 2001, in spite of receiving Operating Aid, the Company went
into liquidation. Following a short period of care and maintenance, Coalpower took the mine
over and once essential maintenance/repairs output recommenced in November 2001.
Output in 2002 has been badly affected by deteriorating geological conditions, particularly at
the main gate end of F114’ s face, the gradient of which has steepened to around 1 in 3. In
October 2002 the main gate contacted a fault and the face was stopped. This has resulted in a
gap in production as replacement face (F123’ s Retreat) development and installation is
completed.
4.11.6
FUTURE MINING PROJECTION
The strategy for the mine is the continuation of a single retreat face working remnant parcels
of High Hazels Seam. Production is anticipated to be maintained at around 600,000t/a until
the High Hazels reaches exhaustion in 2006 or is replaced by production from the Barnsley
seam.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.11.7
PAGE 186
PRODUCTION AND DEVELOPMENT FORECASTS
4.11.7.1
Production
The Draft Five Year Production Schedule is as follows:
Table 4-69
Face
Draft Five Year Production Schedule for High Hazels
2003
2004
2005
2006
Dev (m)
3,428m
3,842m
865m
-
Total
Output
607,000t
606,000t
573,000t
500,000t
F123
F125
F118
F127
Production in 2002 has been limited to around 310,000t due to difficult mining conditions
experienced on F114’ s panel associated with steep gradients at the main gate end of the faces.
The face finally finished prematurely in October due to faulting, also at the main gate end of
the face. This resulted in a production gap at the end of the year while F123’ s Retreat face
development and installation was completed.
The production schedule show the faces being worked at a rate of 7.5 strips per day, the
exception being the much shorter F127’ s Face (170m long), which is shown to be operating at
12.8 strips per day.
4.11.7.2
Development
To maintain continuity of production replacement roadway development has been phased at
60m/week, LH1300 Roadheaders being introduced to drive F118’ s and F127’ s gates. Two
heading teams will be deployed throughout the programme supplemented by a face salvage /
installation team. F125’ s will re-use the old gate of its adjacent face F114’ s.
4.11.7.3
Risk
F123’ s maingate has been driven leaving only a 20m pillar against the adjacent F122’ s face.
The roadway is already showing signs of significant movement and deformation. The
condition of this gate may restrict the level of production.
The development schedule is demanding, particularly given the geological uncertainty of the
areas that are proposed to be exploited. Any shortfall in drivage rates could induce gaps in
face production.
The planned faces are in virgin areas and have projected faulting running very close to their
gate road positions and are at continual risk from minor faulting. This is exacerbated by the
relatively thin seam conditions.
Substantial investment will be required to access and establish mining within the Barnsley
seam and Coalpower have indicated that it is not able to fund this from within its own
resources and that it is unlikely that monies will be able to be secured from commercial
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 187
sources. It must also be borne in mind that the faces planned within the High Hazels are at
high geological risk and that the mine may have to go onto a development only basis whilst
the Barnsley is accessed
4.11.7.4
Longer Term Plans
Substantial reserves/resources of the Barnsley Seam are present within both the Hatfield and
neighbouring Thorne licence boundaries. The Barnsley Seam lies some 70m below the High
Hazels Seam and could be readily accessed by relatively short cross-measure drivages.
Coalpower have outline plans to develop the Barnsley Seam, initial access being via two
relatively short drifts. Longer-term drivages, including a 900m Drift at 1 in 20 for materials
transport and a 225m conveyor drift at 1 in 5 have also been tentatively proposed to create a
base for extending across into the Thorne licence area.
It is envisaged that the mine would produce around 1.25Mt from a single retreat face strategy
utilising two sets of face equipment.
The plans are aligned to the building of a 432MW Power station on site that will be designed
to burn around 1Mt/a. Plans also include for the construction of a second power plant with
the intention of connecting with the Thorne infrastructure and up-rating capacity to 2Mt/a.
4.11.8
OPPORTUNITIES FOR FURTHER INVESTMENT
Since taking over the mine in October 2001 the new management has obviously a very
limited track record. Government operating aid compensated a predicted start-up loss of just
over £2M in only two months for 2002. Further losses were made in 2002 and these have also
been supported by external aid. Output for the mine in 2002 has been disappointing at around
300,000 tonnes saleable. This is not entirely unexpected with both the mining and geological
risks evident in the present High Hazel Seam production area. The mine has an extensive
infrastructure, which has respectfully been starved of any major investment in previous years.
Accepting the risks to achieving acceptable levels of output from the High Hazel Seam
progress has been made to developing the next production face as a retreat longwall.
Unfortunately the Company has not yet been able to finance developments into the Barnsley
Seam. Output next year will be dependent on production from the High Hazel Seam with its
inherent mining and geological risks.
The next few months are critical for the Company to demonstrate that the mine has a future.
In terms of long-term investment schemes, the reserves/resources at both Hatfield and Thorne
are substantial. However, the time scale (let alone cash) to firstly access the Barnsley Seam at
Hatfield and develop and establish the first conventional longwall retreat face is in the order
of two - three years. It has been estimated that such a project may require at least £40M in
capital. If a long-term option were taken on retaining Thorne shafts this would add a further
estimated £800K of annual Care and Maintenance costs. These costs also assumes that a
suitable level of production will be maintained from the High Hazel seam until the first
Barnsley face is brought into production. Without an almost immediate start to the project it
is extremely unlikely that production can be sustained through the period and the mine will
operate on a development only basis.
If the new subsidy scheme provided a minimum of £12M of the required capital, then the
Company, CPL would have to first raise some £28M. As can be seen from Table 6.2.8, if the
projected profit levels were of £5M/annum, it would require a minimum of eight years to
justify acceptable levels of expenditure if discounted at the rate of 8%. Since generating
sufficient cash from the existing operations is extremely remote then it is assumed this would
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 188
be found externally. Obviously, time is not on the side of Hatfield mine and CPL is under
continuing pressure.
Assuming that all the planned faces in the High Hazels seam are proven to be available then
the workings will reach exhaustion in 2006. It must be borne in mind that the planned faces
are at high geological risk and the workings may finish prematurely.
As previously outlined substantial reserves/resources of the Barnsley Seam are present within
both the Hatfield and neighbouring Thorne licence boundaries. Coalpower have outline plans
to develop the Barnsley seam, initial access being via two relatively short drifts. Longer-term
drivages, including a 900m Drift at 1 in 20 for materials transport and a 225m conveyor drift
at 1 in 5 have also been tentatively proposed to create a base for extending across into the
Thorne licence area.
The plans are aligned to the building of a 432MW Power station on site that will be designed
to burn around 1Mt/a of coal. Plans also include for the construction of a second power plant
with the intention of connecting with the Thorne infrastructure and up-rating capacity of the
mine to 2Mt/a.
The connection to Thorne would not be completed for at least 8 years from commencement of
the initial access to the Hatfield Barnsley resources. Thorne would therefore require to be
kept on ‘care and maintenance’ for this protracted period. Estimates for this have varied
between £500k to £1M/a.
Substantial investment will be required to access and establish mining within the Barnsley
seam and Coalpower have indicated that it is not able to fund this from within its own
resources and that it is unlikely that monies will be able to be secured from commercial
sources. It must also be borne in mind that if the High Hazels were to finish prematurely then
the mine may have to go onto a development only basis whilst the Barnsley is accessed.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.12
THORNE COLLIERY
4.12.1
BRIEF DESCRIPTION OF SITE
PAGE 189
The Colliery is situated close to the village of Thorne, adjacent to the M18 and 16km north
east of Doncaster. Mining was established in 1930 and production was halted in 1956. This
was as a direct result of increasing rate of water inflow within the No.2 Shaft. Part of the
shaft wall had collapsed and revealed a very significant cavity, which made the shaft virtually
unusable. Over a period of years first a temporary and then later a more permanent repair was
made to the shaft. This work effectively reduced the diameter of the lower part of the shaft
from 5.9m to 4.9m
Several schemes were considered by British Coal to bring the mine back into production. One
of these schemes considered the sinking of a third shaft and planning outputs of 2.5 and
5.0Mt/a from the reconstructed mine. As prospects for coal diminished through the period
British Coal proposed more modest schemes with the present shafts and winding systems.
Most of the older surface buildings and facilities were cleared. The pit bottom insets and
circuits were repaired. In 1987, British Coal estimated the total cost of the project to bring the
mine back into production as £93M. The Mine has since remained in ‘Care and Maintenance’ .
At privatisation Thorne was taken over on ‘Care and Maintenance’ by RJB Mining (now UK
Coal plc) under a Part II lease licence
4.12.2
MINE BOUNDARIES, OTHER SURFACE CONSTRAINTS AND ISSUES
Boundaries of the High Hazel Seam are set by mine distance limitation with the exception of
the south west. This boundary is set against the Hatfield Colliery workings. Up to the time of
privatisation, there was a single roadway connection between both mines in the High Hazel
Seam workings. This connection has since been sealed.
The High Hazel Seam has been worked extensively up to a radius of 3km from the shafts, at a
maximum depth of 900m. Access has been made into the Barnsley Seam 60m below. The
mine has retained GDO rights.
4.12.3
GEOLOGICAL ASSESSMENT OF THE MINE
Thorne is located in the concealed East Pennine Basin Coalfield, on the northern edge of the
Morley-Campsall Fault Belt, a major NW to SE trending fault zone affecting the Coal
Measures in West and South Yorkshire. The regional dip of the coal measures is towards the
east/north east. The High Hazel Seam, the only seam to be worked at Thorne, lies at a
maximum depth of 900m. This seam has been worked extensively within a 3km radius of the
shaft. Access has been made into the Barnsley Seam, 60m below. The mine has GDO rights
and there are no mining planning restrictions.
The boundaries in all directions except to the south west in the Hazel Seam are set by mine
distance limitations. To the north the resources encroach into what could become the Snaith
prospect. Hatfield Colliery lies 7km to the south west and works the Hazel Seam. Until
privatisation, there was a walkable connection between the two mines with some ventilation
interconnection.
4.12.3.1
Structure
The plans available for this review for Thorne Colliery are very limited in detail of the
geological structure of the mine. In general, it can be determined from workings in the High
Hazel Seam that the trend of faulting is typical for this part of the East Pennine Basin
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 190
Coalfield, that is, most of the major faults trend north west/south east. Some faulting is seen
on the east west trend. These faults are mostly located in the south east portion of the
workings, closer to the Hatfield area.
The degree of minor faulting is not seen on the plans available but is expected from the extent
of the workings to be similar to that of Hatfield.
4.12.3.2
Seams in Reserve/Resources
The following seams are considered to be in the reserve/resource classification for this mine.
•
High Hazel Seam
•
Barnsley Seam
High Hazel Seam Characteristics
The High Hazel Seam is very similar in structure to that at Hatfield, but is shown to have less
dirt and to be for the main part a single bed of coal. The roof to the seam is generally
mudstone, locally canneloid and slightly silty in places. This was known to form a good
working roof to the seam. The floor measures are nearly always mudstone seatearth, rarely
slightly silty in parts. The seam section appears, from earlier workings and from surface and
in-seam drilling, to be a consistent 1.45m thick.
The quality of the High Hazel seam is good with the expected mined section (mostly whole
seam) ash contents ranging between 3 and 5% and the sulphur content ranging from 1.3-1.8%.
Chlorine content is expected to be average at 0.3 to 0.5%.
Barnsley Seam Characteristics
The Barnsley Seam ranges in thickness from 1.90m to 2.80m, and splits to the north east and
eventually becomes unworkable. The thickness variations are usually a function of the total
amount of dirt in the seam. It is generally thinner in the northern areas of the licence with less
dirt than seen in the south. The roof and floor to the seam are expected to be typical of the
Barnsley but details are scarce. It is uncertain whether any of the borehole point information
indicated that sandstones were present on or near the seam in the roof as in parts of the
Hatfield Colliery Barnsley workings.
The quality of the seam is moderate with ash contents of the clean coal in the mined section
varying from 7 to 9% and sulphur content from 1.8% to 2.8% but on average being closer to
2.5%. The chlorine varies between 0.5 to 0.8%.
4.12.3.3
Reserves/Resources Assessment
There were formal reserve assessments made for Thorne Colliery in 1998 and these have
continued through to 2002 unchanged. In 1998, RJB Mining discounted the recoverable
reserves to account for leaving roof coal in the Barnsley and this may change if, under present
practice elsewhere, all the seam is extracted with the consequent increase in the tonnages.
Position with regard to Reserves in 1998
The reserves/resource available at Thorne in 1998 were as summarised in Table 4-70 below
based on the knowledge at that time.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table 4-70
PAGE 191
Thorne Reserve/Resource Summary (01/07/98)
(Source: Hatfield Coal Company)
Million Tonnes
Seam
Reserve
Resource
Total
High Hazel
38.330
38.330
Barnsley
36.992
36.992
Total
75.322
75.322
Mineral Potential
Position with regard to Reserves in 2002
The above position has remained unchanged since the time of the 1998 assessment.
4.12.4
EXPLORATION
As far as can be ascertained, no exploration is planned at Thorne in the near future.
4.12.5
OTHER SEAMS OF INTEREST
There are no other seams of interest at Thorne
4.12.6
IMC COMMENTARY ON THE RESERVE/RESOURCE FOR THORNE COLLIERY
The only comment to make about the Thorne Resources is that they should be at present
downgraded to Mineral Potential. The reasoning for this is that at present the colliery is not a
working mine, and UK Coal plc have to the best of IMC’ s knowledge no intention of reopening the mine again.
The only access at present is the Thorne Shafts and these access the High Hazel Seam. It is
believed that there is access to the Barnsley Seam also at Thorne as stated in the 1998 Review
but this at present is uncertain. The only other access is via Hatfield Colliery, which was,
until privatisation, linked to Thorne via a walkable roadway in the High Hazel Seam. As far
as can be ascertained this access has now been sealed.
With the limitations on access, the zones in both the High Hazel and Barnsley should be
Mineral Potential. There is a possibility that a portion of the resources could be accessed via
Hatfield, but this at present is outside their licence.
A simple summary of the position as IMC regard the situation at Thorne is therefore shown
below:
Table 4-71
IMC Reassessment of Thorne Reserve/Resource Summary: (01/12/02)
Million Tonnes
Seam
Reserve
Resource
Total
Mineral Potential
High Hazel
38.330
Barnsley
36.992
Total
75.322
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
479 KmE
478 KmE
477 KmE
476 KmE
475 KmE
474 KmE
473 KmE
472 KmE
471 KmE
470 KmE
469 KmE
468 KmE
467 KmE
466 KmE
465 KmE
464 KmE
PAGE 192
423 KmN
422 KmN
FE
FW
E
421 KmN
D
420 KmN
419 KmN
SOUTHFIELD
RESERVOIR
AIRE AND CALDER
BEEVERS BRIDGE BH
NAVIGATION
RIVER WENT
C
418 KmN
417 KmN
THORNE COLLIERY
HIGH HAZEL SEAM
WORKINGS
RI V
ER
DO
N
Thorne
Colliery
416 KmN
BELL GREEN BH
Est. Seam 634m BOD
EY
ILL
SW
B
IL
SW
NE
W
JUNC
TIO
N
CA
NA
L
415 KmN
Y
LE
414 KmN
AY
Junction 6
M
18
M
O
TO
R
W
A
Hatfield / Thorne
Connection
413 KmN
RI V
N
ATIO
VIG
NA L
IRE NA
RKSH CA
YO ADBY
UTH & KE
& SO RTH
ELD FO
EFFI STAIN
SH
ER
DO
N
REA
LEASE A
Hatfield Colliery
Workings
SWI
LLEY
60
CK
TRA
RAIL
412 KmN
RIVER DUN NAVIGATION
ILT
RA
Old High Hazel Workings
CK
RA
2
1
411 KmN
Junction 5
29
0
30
ITI
BR
SH
RA
2000
Metres
410 KmN
Figure 4-24
I5104C
1000
IL
Thorne Colliery
High Hazel Seam
Resource
Not to Scale
Thorne Colliery: High Hazel Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
478 KmE
477 KmE
476 KmE
475 KmE
474 KmE
473 KmE
472 KmE
471 KmE
470 KmE
469 KmE
468 KmE
467 KmE
466 KmE
465 KmE
464 KmE
PAGE 193
423 KmN
422 KmN
Low Barnsley Bottom Bed
Splits and Deteriorates
421 KmN
420 KmN
ow
e/L lit
s
ou Sp
n H ley
e
r
ar rns
W Ba
EC
419 KmN
Warren House / Low Barnsley Split
D3E
EW
CW
418 KmN
D3W
D2
417 KmN
416 KmN
Thorne
Colliery
Possible Planned Barnsley Workings
at Hatfield Colliery
415 KmN
AC1
AS
413 KmN
412 KmN
Hatfield Colliery
Barnsley Workings
411 KmN
AN1
Ba
Sea rnsley/
m S Dun
epa sil
ratio
n
Low
B
Spli arnsle
ts a
y
nd D Botto
eter m Be
iora
d
tes
414 KmN
er
Rid
D1
plit
lS
a
Co
d)
pe
ap
M
ot
(N
plit
S
l
oa
rC
e
d
i
fR
eo
n
i
L
ble
ssi
o
P
CE
BW
BE
AN2
AC2
a
e Are
Leas
Thorne Colliery
Barnsley Seam
Resource
Not to Scale
Old Workings
Upper Part of Day
Beds Split Off
0
410 KmN
Figure 4-25
I5104C
1000
2000
Metres
Thorne Colliery: Barnsley Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.12.7
PAGE 194
MINE CHARACTERISTICS AND CONSTRAINTS
The mine comprises two shafts, modern winding systems, a pit bottom infrastructure, and
substantial storage buildings on the surface within a limited surface area. It has been estimated
that the shafts would support a saleable output of 1.25Mt. Significant capital would be
required to provide coal preparation, mineral handling and dispatch facilities and surface
welfare amenities. Importantly there is no planning permission for on-site discard tipping.
Major drivages would be required underground to access the High Hazel seam and provide a
modern infrastructure for potentially limited output. A minimum of two cross measure drifts,
some 250m in lengths and dipping at 1 in 4 would be required to access the Barnsley seam.
In the present commercial situation UK Coal plc have recently registered, their intention not
to proceed any further with possible operational interests. They have stated their intentions to
cease pumping and withdraw from the limited mine circuit. At present there is an option being
considered through The Coal Authority for the transfer of the mine licence. The prospects to
other potential operators to produce coal from the Thorne site appear remote. However, access
to the areas of coal and longer-term use of the shafts for non-coal winding activities may
promote interest from Hatfield Colliery. It is worth noting that Hatfield already has access to
long-term areas of coal within its own licence and has the possibility of extending into Thorne
without using its shafts. This being the case the most likely situation is that Thorne will close
and the shafts filled.
4.12.7.1
Ventilation
The mine is under care and maintenance and ventilation is adequate provided by the Natural
Ventilation Pressure developed by the difference in ambient underground temperature at the
bottom of the upcast shaft and the surface ambient temperature.
4.12.7.2
Subsidence
High Hazels Seam
Reserve Zone FW: Mining in this area would affect the Villages East Cowick and
Rawcliffe as well as the M62 and Knottingley/Goole Railway. The River Aire lies in this area
above the height of the surrounding land.
Subsidence damage costs will be high and likely to be in excess of £2/t.
Reserve Zone FE: This area contains the M62 and M18 Motorways and a complex
interchange. The Knottingley-Goole railway crosses the area with the Aire and Calder
Navigation lying along the south boundary. Rawcliffe village will affected and, in IMC’ s
opinion, subsidence damage costs will be sufficiently expensive to potentially preclude
mining.
Reserve Zone E:
The M62 and M18 Motorways cross this area with the River Don lying
along its western edge. Parts of this area are as little as two metres above sea level. The Dutch
River is a major drainage feature. Goole town occupies an area at the northern edge with the
Doncaster-Goole and Pontefract-Kingston Railways are affected.
A major drainage scheme would be required for this area and in our opinion, the subsidence
damage costs are likely to be in excess of £2.50/t.
Reserve Zones A, B C and D:
These areas include Goole in the north and Crowle town
in the south, as well as the Doncaster-Goole railway in Zone D and the major Swinefleet
Warping Drain. Land is low lying at some three metres above sea level draining to the River
Ouse in the north of Zone D.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 195
Major damage prevention works will be required; these may well be in excess of £2/t.
Barnsley Seam
Reserve Zone EW and EC: The M18 Motorway crosses both areas and the land is low lying
with the River Don flowing just outside the western boundary.
Major drainage works will be required and costs will exceed £2.50/t
Reserve Zone D1 and D2: The towns of Thorne and Moorends occupy most of the area of
Zone D1 with Moorends extending into Zone D2. The M18 motorway and the DoncasterGoole Railway cross both areas.
Subsidence damage costs in Zone D1 may well exceed £5/t but costs for Zone D2 may exceed
£3/t.
Reserve Zone D3W and D3E:
The Doncaster-Goole railway continues into Zone D3E.
Otherwise, the main overriding consideration is drainage. The land is low lying and major
drainage works are likely to exceed £2.50/t.
Reserve Zone AS, AC1, AN1, AC2 and AN2:
Thorne occupies a portion in the west of
Zone AS otherwise there are few buildings in these areas. Of greatest concern is drainage
with land as little as two metres above sea level.
Subsidence damage costs are likely to exceed £2.50/t.
Reserve Zone BW, BE, CW and CE:
Drainage is the main concern in these areas with
the major Swinefleet Warping Drain close to Zones CW and BW. Major works will be
required if the High Hazel has been mined earlier, then costs for the Barnsley Seam could be
in the order of £5/t.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.13
TOWER COLLIERY
4.13.1
BRIEF DESCRIPTION OF SITE
PAGE 196
Tower Colliery is situated in Mid Glamorgan west of the village of Hirwaun and lies south of
the main A465 ‘Heads of the Valleys’ trunk road. The mine is connected to the rail network.
The mine was first established in 1864. Over the years some nine seams have been worked
from as many as eight access points. The colliery has also been combined with two adjacent
mines, Fernhill (in 1964) and Mardy (in 1986) both of which have since been abandoned (in
1982 and 1991 respectively).
The mine entries are now confined to a single shaft (No.4), and a surface drift (No.3), which
are located at sites some 1km apart. No.4 Shaft, which was sunk between 1941 and 1943, is
4.88m in diameter and 162m in depth. The No.3 New Drift (which was established in 1958)
is 1,680m long and dips at a gradient of 1 in 5.2.
The main management and administration buildings are located at the No.4 Mine site, which
covers an area of about 5 hectares. The No.4 Shaft is used for manriding and materials
transport and return ventilation.
The No.3 New Drift provides intake ventilation and houses the main mineral conveyor. The
drift site has an area of approximately 23 hectares and has coal preparation plant and stocking
and despatch facilities capable of handling a range of products. In addition there are tipping
areas and non-operational land totalling around 184 hectares.
Due to market constraints British Coal closed the mine in April 1994. After a period of ‘care
and maintenance’ the mine re-opened in January 1995 with a workforce buyout who continue
to operate the mine under the company name Tower Colliery Limited.
4.13.2
MINE BOUNDARIES, OTHER SURFACE CONSTRAINTS AND ISSUES
The licence area is defined by the large Glyncorrwg fault to the west, old deep mines and
opencast workings to the north, with faults and old workings to the east and south.
There are up to fourteen named seams within the licence area at Tower Colliery. The only
seam presently worked is the Seven Feet/Five Feet, which is a combined seam of several
leaves. In the present working it offers typically 1.20m of coal in a cut section of 1.50m. The
product is a low volatile, marginal anthracite coal and bulk sales are to Aberthaw Power
Station, which is designed specifically to burn low volatile coal.
4.13.3
4.13.3.1
GEOLOGICAL ASSESSMENT OF THE MINE
Introduction
In this section the geology of the mine and reserve zones are discussed for Tower, which lies
on the northern margin of the South Wales Coalfield, northwest of Aberdare. Tower has
previously been combined with the now-closed Fernhill and Mardy collieries, to the south and
east. The Pentreclwydau South mining licence area lies west of the present working district.
The mine’ s overall resources are not thought to have been fully assessed since the 1980’ s, and
this report is therefore relatively wide-ranging. The Appendix Table 1 summarises the seam
sequence in the Tower area, and Table 2 the Reserves, Resources and Mineral Potential as
assessed in this study.
The mine entries lie on the Middle Coal Measures outcrop; the single shaft (Tower 4) is c.
1.6km WSW of the surface drift entries. South of the shaft, the ground rises steeply at the
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 197
north-facing scarp slope of the overlying Upper (Pennant) Coal Measures. The combination
of rising ground and a southerly seam dip gives significant southerly increases in cover to the
surface. In the southerly area around Fernhill, however, the surface elevation again reduces, in
the upper reaches of the Rhondda Fawr valley.
The succession (Table 1) is typical for South Wales. The coal-rich Lower and Middle Coal
Measures are characterised by many seams, in a generally mudstone-dominated succession.
Sandstones with fewer, generally thinner seams, dominate the Pennant Measures. There are
no overlying Permian or later solid formations. Superficial deposits are present throughout
much of the mine area, with common peat on higher ground. There are local areas of surface
instability, particularly along the margins of the higher ground. Opencasted ground lies to the
north of the mine area. There are no significant cover issues other than those associated with
old workings, although probable water-bearing strata, brought close to potential resources
adjacent to large faults, are noted later. There are no igneous features of mining significance.
Most remaining reserves and resources are anthracites.
4.13.3.2
Structure and Landslips
The Coal Measures are deformed by normal faults, together with thrusts and other
compressional disturbances. The Lower and Middle Coal Measures are more deformed by the
compressional disturbances than are the Pennant Measures.
•
The normal faults have throws between <1m and >100m, and commonly strike NW-SE
(these are known as “ cross faults” in South Wales). The larger normal faults are named,
and are significant mining boundaries. The Glyncorrwg Fault has a westerly-downthrow
probably >300m in the resource sequence, and forms the effective western boundary to
the present mining area. The Pentreclwydau South mining licence lies beyond, to the west.
•
The Fernhill Slide is a W-E striking normal fault in higher seams, probably with a
progressively lower fault plane dip to depth. It appears to eliminate otherwise-relevant
areas of coal in the Six Feet and Nine Feet seams, in the area south of Tower No. 4 shaft.
•
Thrust faults and associated folds commonly strike SW-NE in western areas, and more WE in eastern areas. They have “ throws” between <1m and >100m, commonly <5m. They
are particularly prominent between the Two Feet Nine and Nine Feet seams.
•
The larger thrusts are thought to terminate laterally at the larger cross faults.
•
Bedding dips are typically 50 to 100 to the south, with some steepening near larger faults;
in the west, and across the Pentreclwydau South area beyond, westerly dips are present.
•
The seams are intensely cleated, and further fractured by full-seam slips.
Surface instabilities include landslips/scree slopes, and potentially unstable crags. Most of
these features lie along the Pennant Measures scarp, including the slopes above the Rhondda
Fawr. A detailed account is beyond the scope of this report; surface constraints are, however,
well understood at the mine, and accommodated in the mine planning process.
4.13.3.3
Reserves, Resources, and Mineral Potential
Introduction; licenced areas
The Tower licence area is bounded on the east by the Hirwaun No. 2A Fault, on the south by
Northing 199400, and on the west by a line sub-parallel to, but >500m west of, the likely
position of the Glyncorrwg Fault in the resource seam sequence. To the north lie various
worked opencast sites, and old workings from the closed Rhigos and Cwmgwrach collieries.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 198
The Pentreclwydau South licence area (which is not, at the time of writing, applicable to
Tower) is west of the Glyncorrwg Fault. Its northern boundary is parallel to the Neath
Disturbance, a major fault zone that strikes SW-NE along the axis of the Neath Valley. The
licence area extends west between 2km and 4km from the Glyncorrwg Fault; the N-S extent is
locally >5km. Various seams, particularly in the Pennant Measures, have been mined. The
Pentreclwydau South drift mine was developed from the north during the 1990’ s, and worked
limited areas of the Six Feet Seam by partial extraction, prior to closure. The licence area
contains the largest potential resource that could be available to Tower, key seams being the
Six Feet and Nine Feet. It is very poorly proved, other than by extensive over-workings in the
No. 2 Rhondda Seam, 100’ s of metres above the key seams. Access from Tower would
require cross-measures drifts through the Glyncorrwg Fault. The throw of this fault in the
Pennant Series is >300m in places; at depths applicable to the resource seams, the throw is not
known. On the assumption that it is at least as large as in the near-surface, the drivages would
be major, both in length, and in the width of deformed ground that would be traversed. It
should be noted that throws of 300m or more would juxtapose water-bearing Carboniferous
Limestone with the resource sequence, and details would be required for mine planning.
Seams of Interest
The following are considered valid for reserve, resource, and mineral potential zones.
•
Six Feet
•
Nine Feet
•
Seven Feet/Five Feet (the presently-mined seam)
These are now described in descending order, with comments on seam quality and thickness,
roof and floor, and outline assessments of their varying reserve status.
Six Feet Seam
This seam has been worked very locally at Tower, and more extensively in neighbouring
mines. The seam splits into two main coalbeds (the Upper Six Feet, and the Middle/Lower
Six Feet of the standard South Wales nomenclature) in the area south and east of Tower. A
full Six Feet Seam, typically mainly coal, >2.0m to >3.0m thick, is present in the area that has
been mined in recent years in the Seven Feet/Five Feet, and there is also a united seam in the
Pentreclwydau South area. The seam-less-dirt ash is around 2.5% to 7.5%, and sulphur
around 0.60% to 0.75%. The seam rank is NCB Coal Rank Code 200 in the east, up-ranking
to anthracite, CRC 100 in the west.
The roof of the united seam has not formally been mapped. It is known to be variable, and to
include local sandstones (as on the single face worked at Tower in the 1980’ s). The key roof
characteristic in all the relevant mines is the “ rashings” : sheared and weak mudstones, locally
with coal streaks, with very variable thickness, reflecting deformation by small thrusts within,
or adjacent to the seam. In neighbouring mines, significant thicknesses of supporting top coal
were locally left, to allow effective mining beneath the rashings. Any inclusion in the worked
section leads to difficult roof control, and excessive dirt in a mined section. The seam was
extensively worked by longwall mining at Cwmgwrach Colliery, northwest of Tower, where
significant thicknesses of top coal appear to have been used. The floor of the Six Feet is also
commonly sheared mudstones.
The Six Feet is not considered sufficiently well-understood at present, for reserves status.
However, the extensive area of united seam across the western parts of the mine suggests that
some Resources should be included at Tower. At Pentreclwydau South, the expected
continuation of a thick united Six Feet suggests that significant Mineral Potential could be
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 199
available to Tower, given major development through the Glyncorrwg Fault, and transfer of
the mining licence. In summary, the Six Feet is considered to offer two main areas of
potential interest, as follows.
•
Six Feet Resources: Tower licence area. Where unworked, between the Glyncorrwg Fault
in the west, and the (generalised) locus of seam splitting in the east. The seam is assumed
absent in the Fernhill Slide area, further constraining the resources on the eastern side.
•
Six Feet Mineral Potential: Pentreclwydau South licence area west from the Glyncorrwg
Fault. This is too poorly-proved to be classed as resources, even if the mining licence
were transferred.
Nine Feet Seam
The Nine Feet Seam is typically 2.0m to 3.0m thick, mainly coal, over most of the Tower
area, and has been very extensively mined. Regionally, the seam has three main coalbeds,
which are united over most of the area under consideration. The Lower and Middle Nine Feet
split southwards along a W-E trend, south of the main worked area at Tower; the combined
Upper/Middle Nine Feet is still c. 2.0m thick beyond this. The split is expected to be present
across the southern parts of the Pentreclwydau South licence area, but there are no details.
The seam has not been formally mapped. The seam-less-dirt ash is expected to be around 3%
to 5% over wide areas, with the sulphur typically 0.7% to 0.8%. Within the Tower area, the
coal rank is marginally lower (NCB Coal Rank Code 200) than at Pentreclwydau South
(anthracite, CRC 100). The Nine Feet roof is thought to be typically a sheared mudstone;
some sandstones are known. The Nine Feet floor is usually a mudstone seatearth, which is
also likely to be sheared.
There are various unmined areas within the Tower licence area, two of which are considered
to provide Mineral Potential, and which could be linked with any future developments into
the Six Feet. One area lies south of the Main West Laterals (which serve the Seven Feet/Five
Feet working districts); the viability of this area depends upon detailed interpretations of the
Fernhill Slide, and would require significant new proving. The other, probably smaller area
lies north of the Main West Laterals. Other unworked areas in the Nine Feet are considered
too small, or definitely inaccessible from modern workings. At Pentreclwydau South, the
Nine Feet could be technically accessed together with the Six Feet.
In summary, the Nine Feet is considered to offer the following areas of interest.
•
Tower licence area: two Mineral Potential zones.
•
Pentreclwydau South licence area: one, possibly large, Mineral Potential zone, subject to
licensing, proving and investment.
Seven Feet/Five Feet Seam
This is a composite seam, with several coalbeds separated by dirt layers, all of which vary
significantly in thickness. The full seam comprises the three coalbeds of the Seven Feet, with
three coalbeds of the underlying Five Feet; the present workings extract only the Upper Five
Feet/Lower Seven Feet combination. Inclusion of the Middle Seven Feet is detrimental
regarding sulphur content. The unknown extent of a viable Upper Five Feet/Lower Seven Feet
combination (in terms of both thickness and coal content) is one constraint on the practical
limit of reserves at Tower. It is known that this combination ultimately fails to the west, but
data are very sparse; the seam is expected to be split and worthless over most or all of
Pentreclwydau South. It is thought probable, however, that a viable seam does extend north
towards the old Cwmgwrach workings. The roof of this seam combination is typically a
mudstone/siltstone, although sandstones are locally present, and there is a gradation into
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 200
seatearth where the Middle Seven Feet lies close above (in the north of the present reserves).
The floor is typically a seatearth, which locally includes siltstones with some sandstones.
The laid-out panels within the working district are subject to varying geological risk, which
may be summarised as follows.
•
V47’ s (Reserves: working panel). This is blocked out, together with structural cover from
workings above; no significant geological risks are expected.
•
V49’ s (Reserves: blocked out). The seam section is viable. However, the northern c. 250m
is faulted, and a limited panel run is therefore expected. Also, the southern c. 100m
includes steep ground, and some of the panel area is not over-worked in key seams; at the
time of writing, the area north to the known faults is expected to be workable.
•
V44’ s (Reserves: north of the Main West Laterals). This has yet to be developed.
However, it is considered that a viable seam section is likely to persist, and there is
extensive over-working in the Nine Feet Seam, providing some structural cover
•
V46’ s, V51’ s, V53’ s (Resources: west of V44’ s/V49’ s). The seam section requires
proving (by mine drivages). The steep ground proved at the southern end of V49’ s is
expected to cross the southern end of the V51’ s. Normal faults proved in the northern part
of V49’ s may also be present within the northern part of V51’ s. Parts of the laid-out area
are not overworked in any relevant seam, giving a higher fault risk. The V51’ s and V53’ s
encroach into the old Glyncorrwg shaft area. The V51’ s straddles the present Tower
licence boundary and V46’ s/V53’ s lie beyond it (it is understood that a licence extension
has been applied for). Classification as a Resource, rather than reserves, reflects the
uncertain seam section, fault dispositions etc.
•
Other unworked ground north of the Main West Laterals (Resources). It is considered that
there is scope for two other Resources panels to the north, subject to detailed planning.
•
“ Motorways” area (Reserves). Subject to viability appraisals there maybe scope for partial
extraction of thick, multi-bed Seven Feet/Five Feet just southwest from the shaft. This
could be the final extraction, as mining here could destroy accesses to the west.
•
South of V29’ s (Mineral Potential). Subject to a detailed geological appraisal there maybe
scope for limited partial extraction in an unworked area some 2km south of the shaft.
Other Seams of Interest
A recent review of mining prospects across the Tower area has led to the conclusion that no
other seams are relevant to future deep mining.
4.13.3.4
Summary of Reserves, Resources and Mineral Potential
Table 2 summarises IMC’ s evaluation of the present reserve base at Tower. Pentreclwydau
South is included as it is technically accessible from Tower. However, note that a major
ownership and strategy review would be necessary regarding any incorporation of the
Pentreclwydau tonnages into Tower. The strategy review would necessarily be far-reaching,
involving long-term marketing, surface facilities including tipping and coal disposal, and
underground infrastructure and ventilation. Obviously, very considerable investment is
implied, and this should include significant investment in geological exploration, see 4.13.3.5.
4.13.3.5
Exploration
Historical exploration at Tower has been almost exclusively by underground boreholes. This
mainly reflects the availability of underground workings, and the difficulties of drilling from
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 201
the surface (uplands, extensive forests, etc). There are common old workings that would
further add to the costs of surface borehole exploration. The surface topography is difficult for
seismic acquisition.
The surface is also mainly forested uplands across the Pentreclwydau South area, where there
is a need for essentially primary exploration, as structural proving is largely limited to
information from shallow workings, which would be only marginally relevant to any
proposals involving the Six Feet and Nine Feet seams. Even the largest faults are not
constrained at depth, and some seismic acquisition would be necessary, despite surface
limitations.
The following notes summarise likely exploration scenarios for the two licence areas.
Tower licence area
•
Structural proving. This is expected to be limited largely to mine drivages with occasional
in-seam geophysical surveys.
•
Six Feet and Nine Feet seams. Underground drilling would be recommended for these,
wherever underground sites (in the Seven Feet/Five Feet) became available. Such drilling
would substantiate seam sections and qualities, and determine roof and floor character, as
well as adding to the structural knowledge. Regarding the Nine Feet area south of the
Main West Laterals, this could only be drilled from a new drivage in the Seven Feet/Five
Feet, south into the area suggested for potential partial extraction, south of the shaft.
•
Seven Feet/Five Feet Seam. Both seam section and detailed structure would be best
determined by mine drivages. There is scope for continuing underground geophysical
surveys for detailed fault determinations.
Pentreclwydau South licence area
Detailed assessments are beyond the scope of this report; the following notes are only first
indications of the work that would be required to up-rate the licence area for a dependable
mining proposal.
Structural proving.
•
The full licence area requires an initial desk study of existing data.
•
This should be followed by an initial, targeted exploration programme involving drilling
(to at least 100m below the Nine Feet Seam) and some 2D seismic. The exploration
should include coverage of the Glyncorrwg Fault (see earlier).
•
More detailed exploration, following this initial phase, would be inevitable.
•
On the assumption that any mining proposals would involve re-instatement of the
Pentreclwydau South mine entries and Six Feet workings, it should be noted that the most
valuable exploration method would be significant southerly extensions of the main
drivages.
Six Feet and Nine Feet seams
These seams are barely proved, apart from the area immediately around the Pentreclwydau
South accesses. On regional grounds, the Six Feet is expected to be a single united seam
across the area, but this requires substantiation by drilling. Further, the Nine Feet (which may
be the seam of choice, in terms of structural deformation), is expected to split in the southern
part of the area, and this requires targeted drilling.
Other seams
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 202
There are unlikely to be other seams of mining interest, but given the lack of exploration this
must remain uncertain.
4.13.3.6
Geological and Reserve/ Resource Conclusions
The following conclusions are drawn.
Five Year Plan
•
The blocked-out V47’ s and V49’ s are expected to be worked according to plan.
•
The planned V44’ s, together with another as-yet unplanned panel north of the Main West
Laterals, are likely to provide continuing production from the Seven Feet/Five Feet, albeit
at greater geological risk. Detailed risk reduction procedures (optimum development
drivage timings and locations, in-seam geophysical surveys) are essential for successful
extraction.
•
The V51’ s, V46’ s and V53’ s units are not considered in any way dependable, on present
evidence.
Beyond the Five Year Plan
•
It may well be that the three Reserves panels identified above (V47’ s, V49’ s and V44’ s)
are the only workable longwall units left in the Seven Feet/Five Feet Seam. (although it is
possible that at least one other longwall will be available between V44’ s and V40’ s, after
detailed planning and development proving). Therefore, if Tower is to continue
production at or around present output levels, new accesses into different seams will need
to be made sooner, rather than later.
•
Within the Tower licence area, it may be possible to replace Seven Feet/Five Feet output
from the Six Feet, possibly supplemented by residual Nine Feet. An in-depth study of the
Six Feet, in terms of its varying geological and mining settings, optimum extraction
method and equipment, etc, would be necessary prior to detailed planning.
•
The only longer-term resource available to Tower is the adjacent Pentreclwydau South
licence area, in the Six Feet and Nine Feet seams. This would require a licence transfer,
and very substantial study and investment.
•
A trial working of the Six Feet within the Tower licence area could inform workability in
the larger Pentreclwydau area.
The following table is a summary of Table 2 below in this section. The appendices and plans
are shown at the end of this section on Tower Colliery:
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Table 4-72
PAGE 203
IMC Re-assessment of Tower Reserve/ Resource: Summary (01/12/02)
Million Tonnes
Seam
Six Feet (Tower licence area)
Six Feet (Pentreclwydau South
licence area)
Nine Feet (Tower licence area)
Nine
Feet
(Pentreclwydau
South licence area)
Seven Feet / Five Feet (Tower
licence area)
Total
4.13.4
Reserve
Resource
Total
Mineral Potential
-
< 5.0
-
< 5.0
-
9.0
-
-
-
< 3.0
7.0
2.6
1.3
3.9
Not quantified.
2.6
<6.3
< 8.9
c. 19.0
MINE CHARACTERISTICS AND CONSTRAINTS
Tower works a single retreat longwall and the rate of extraction is primarily market driven.
Roadway drivages are supported on steel arches throughout the mine. Significantly, Tower
has maintained drivage rates that compare favourably with the best being achieved elsewhere
in the UK. This important factor has enabled the mine to retain sufficient lead-time between
developments and replacement faces, to ensure continuity of production. Underground
transport of materials is by rope haulage on steeper gradients and Free Steered Vehicles
elsewhere.
Access to the mine is via the No.4 shaft and manriding on conveyors is extensive throughout.
These manriding systems are an essential factor in maintaining acceptable machine available
times as production areas extend further westwards. Planned annual outputs have regularly
been achieved since privatisation. This is set against a background of limited resources and in
some areas, difficult mining conditions. Outside the effects of previous seam workings, gas
emission rates at Tower can be high and effectively constrain output for lengthy periods. In
other areas water logged old workings are also a constraint. Precautions will need to be taken
against inrushes from these old workings, and are a continuing statutory requirement prior to
extending the working areas.
Over the last few years, Tower, like all other UK deep mines, has come under increasing
commercial pressure from reducing proceeds within a highly competitive market. The mine is
aware of the present situation and is reviewing its forward planning to minimise risk and
where ever possible have flexibility to react to changing circumstances, both in the market
and operationally within the mine.
Under the present plan, developments for face replacements are based around a westerly
extension to the existing area, and continuing with the present mine infrastructure. The latter
was observed to be of a good standard throughout, with the exception of a section of roadway
some 100m in length. This section in the Main Intake was under repair and enlargement.
Maintaining two-way manriding facilities throughout the main intake is a prime objective for
the mine.
It is recognised that the production plan is subject to geological risk through seam splits and
faults within the development area. As the workings extend to the limits of this area, viability
will certainly be constrained by substantially increased distances and associated travelling
times. These increased distances will also make it more difficult to adequately ventilate the
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 204
working districts. At present ventilation requirements are limited to two or three
developments and a production face.
Outside the present plans for workings in the Seven Feet/Nine Feet Seam the mine is carrying
out longer-term strategic planning. This work is aimed at examining potential options that
might be available within other seams, and accessible by drivages from the present
infrastructure.
4.13.4.1
Ventilation
Ventilation at this mine is by a combination of main and booster fans. The booster fan being
installed at the outbye end of M2 Motorway Return. The faces are retreat longwalls utilising a
back-airway system of ventilation. Whilst there is from necessity sufficient ventilation for the
production unit, this does reduce the ventilation available for the main laterals and gate road
development. This has resulted in the use of series ventilation for many developments, which
is not good practice.
Back-rips (roadway enlargements) are taking place to increase the cross-section of the
roadway and therefore reduce the ventilation resistance. This is unlikely to allow the booster
fan duty to increase sufficiently to improve the ventilation airflows significantly. There may
be a requirement to introduce additional fans at the booster fan site. In addition, there is a
short length of parallel roadway, which is to be driven near the shaft bottom area to reduce
pressure loss and improve ventilation and environmental conditions. The main problem is that
any extra working developments cannot be ventilated including developments to other seams.
There is a requirement for a ventilation pressure/quantity survey to enable a new ventilation
network to be formulated for future ventilation planning.
The methane drainage system is operationally efficient and as long as the standards are
maintained then this should assist in the removal of methane. The surface gas extraction plant
utilises a number of Nash H10G gas extraction pumps which are towards the end of their
operational lives (these are no longer manufactured and are becoming unsupportable) and
need replacing with CL 3002 pumps.
4.13.4.2
Subsidence
Seven Feet/Five Feet Seam Panels V44 and V46’s:
Panels V44’ s and V46’ s
are scheduled to start production in 2005 and 2007 respectively. These panels are presently
planned to stop working at a plan distance equivalent to half the depth of the seam from a
high-pressure gas pipeline. Transco may insist in preventive measures being undertaken
under the shared cost agreement. The mine management is considering stopping these faces
short in order that no costs are incurred in respect of the gas main. Panel V46’ s may come
within influencing distance of a landslip and the Rivers Corrwg Fechan and Corrwg will be
affected. The remaining affected area is mainly forestry with no built-up areas.
Subsidence damage costs are likely to be low at less than 10 pence/t but the colliery
management is concerned about land-slippage and have commenced a study. The Licensing
Authority will also be concerned about the possibility of landslips and if a landslip occurs,
subsidence damage costs and remedial works could be very expensive. The Licensing
Authority may be sufficiently concerned about landslipping such that security required would
preclude viable mining.
Seven Feet/Five Feet Seam Panels Panels V49’s, V51’s and V53’s:
All these panels
would also work under a rural area, much of it forest. Streams will be affected as will a
number of colliery waste disposal tips. There are a number of former landslips in the area.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 205
The potential for re-activation is currently being assessed on behalf of the colliery
management.
Seven Feet/five Feet Seam (Area to the North of Panels V45’s and V47’s):
predominantly woodland but there are some landslips.
The area is
Seven Feet/five Feet Seam (Area to the North of Panel V27’s): This area would be
worked by partial extraction. The Llyn Fawr reservoir would be affected and there is a
landslip adjacent to the reservoir. There are several landslips in the area. The area is also
crossed by a high-pressure gas pipeline.
Nine Feet Seam (area east of Rhigos Fault):
This area is largely forest and although
there are no landslips, a high-pressure gas main could be affected.
Nine Feet Seam (area west if Dinas Fault):
contains several landslips.
This is predominately-wooded area but
Nine Feet Seam (Pentreclwydau South Licence Area):
contain a high-pressure gas main and several landslips.
This is mainly woodland but does
Six Feet Seam (Pentreclwydau South Licence Area):
As for Nine Feet Seam.
Area between Glyncorrwg Fault and Cwmgwrach Fault:
gas main and landslips in this area.
There is a high-pressure
Subsidence Damage Costs in Tower Colliery Reserves Area: The Coal Authority has a
duty to ensure that sufficient funds are available for the mine operator to remedy subsidence
damage. In the event of landslip occurring there is a potential for considerable costs. The Coal
Authority may well ask for, as noted earlier, amounts of such a high magnitude to be bonded
that areas of coal around known landslips would in effect become sterilised. Many of the
reserve areas are large, however, and extensive mining may be possible.
In the absence of landslips, subsidence damage costs are likely to be less than 10 pence/t.
4.13.4.3
Coal Preparation Facilities
The current Coal Preparation Plant was commissioned in 1988, at 300t/h capacity. Dry fines
extraction was added in 1992 increasing the feed capacity to 450t/h of ROM. If the need
arises the potential plant capacity is around 45,000t/w equating to 2.16Mt/a.
The coal arrives at the washing site from the No.3 drift, discharging into a 500t bunker with
overspill facilities to ground. The feed to the plant is from the base of the bunker via a
variable speed weigh feeder onto a dry fines extraction screen, the underflow being the dry
constituent of a PSF. The oversize is conveyed to a grizzly screen to remove the +175mm.
The 175mm – 0 is the feed to the washing plant, the oversize is put to ground, hand sorted
with the coal being broken to rejoin the washing plant feed.
Feed to the CPP, now reduced to 300t/h, is passed over pre-wet screens to remove the
25mm-0; the oversize 175mm-0 is fed into a two Product Dense Medium Bath. This
producing a cleaned coal, which is classified into standard domestic, grades and ground
stocked in dedicated bays. The screen undersize flows to desliming screens, the overflow
from which is pump fed into a single Dense Medium Cyclone, again producing cleaned coal
of a smaller size fraction, washed smalls; this is centrifuged and ground stocked.
Underflow from the desliming screen, a mixture of fine solids and water, is fed to a froth
flotation plant. The recovered is dewatered on a Vacuum Horizontal Belt Filter, which
discharges onto the dewatered washed smalls conveyor. The tailings from the cells are
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 206
recovered and dewater in a Multi-Roll Filter, allowing the water to be re-circulated for further
use within the washing process.
The product processed from the ROM is classified as “ Low Grade” anthracite. The current
vend is around 50% in the ratio of 25:75, Domestic to PSF. The PSF blend is a mixture of
washed smalls and dry fines in variable proportions to suit the market requirements. Some of
the washed fines are sold for briquetting. The domestic grades are re-screened, wet, before
despatch to ensure a top quality product.
There is about 70,000 tonnes of ROM on stock, which will be pulled back during the winter
period without detriment to the current plant capacity.
4.13.5
HISTORIC PERFORMANCE
4.13.5.1
Production
Table 4-73
Historical Production Performance at Tower
Tower
1999
2000
2001
2002
(9 months)
Actual Output
million tonnes – saleable
0.464
0.598
0.642
0.502
Budgeted Output
million tonnes - saleable
0.610
0.630
0.630
0.486
Difference
million tonnes - saleable
-0.146
-0.032
+0.012
+0.016
Production in 1999 was badly affected by adverse geology causing difficulty in completing
the development of V40’ s. Shortly after the face was brought into production a significant
inflow of mine gas occurred that resulted in a cessation of mining operations for a period of
two months.
4.13.6
FUTURE MINING PROJECTION
The strategy is to continue production from a single retreat face concentrated in the Seven
Feet/Five Feet Seam in an area to the South West of, and some 6.5km from, the mine entries
at a depth of around 600m. Two sets of face equipment are utilised to avoid production gaps.
Production in 2002 is expected to be in-line with budget at around 650,000t. It is planned to
continue production at or slightly above this level.
4.13.7
4.13.7.1
PRODUCTION AND DEVELOPMENT FORECASTS
Production
Face design has been standardised at 303m wide with an extracted height of 1.70m. The
faces have been laid out parallel to each other separated by suitable pillars (around 80m
wide).
V47’ s is currently in production and is planned to reach exhaustion by the beginning of
March 2003 when it will be replaced by V49’ s, which has been blocked out and is currently
being equipped. V49’ s has a face run that is restricted by faulting to 1170m and is planned to
continue in production until March 2004.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 207
Based on past performance the faces are phased at around 30 strips/w, which yielding around
483t/m is equivalent to over 11,000t/w. This is supplemented by coal generated within the
development drivages and the ability to blend raw fines back into the product.
V49’ s is to be replaced by V44’ s that has a planned run of around 1,040m. The face has in
part been overworked in the Nine Feet seam and is relatively secure. Assuming that the full
planned run of the panel is developed then it will have a life of around 11 months, taking
production to February 2005.
Three further faces are shown as being potentially available to the west, V51’ s and V53’ s to
the south and V46’ s to the north of the extension of the colliery infrastructure. These faces,
particularly V51’ s and V53’ s are at significant risk from faulting, steep gradients and seam
thinning.
4.13.7.2
Development
Two development teams manned by outside contractors are shown deployed throughout the
plan. As alluded to above the development of V49’ s has been completed and the face is
currently being installed. The development of the laterals to access the gate roads for V44’ s
have commenced and are ongoing phased at 30m/w setting steel arches. It is anticipated that
the gate roads will be established during February and March 2003. Once fully established
the gate roads are phased at 60m/w setting flat top steel arches. These rates are firmly based
on historic performances.
4.13.7.3
Risk
Face production is at risk from minor faulting particularly to the south, which is in a virgin
area.
The planned faces to the west beyond V49’ s and V44’ s are at significant geological risk
particularly with regards to minor faulting, steep gradients (to the south) and seam thinning.
The utilisation of retreat mining with the pre-driving of the gate roads will assist in reducing
this risk.
Tower Colliery is recognised as being a ‘gassy mine’ with relatively high levels of methane
emissions. However, the mine management has extensive experience of the control of
methane and significant improvements have been made to the mine extraction systems in
recent years. The further improvements recently undertaken should minimise impact on
production still further.
As the mine continues to extend west the workings are becoming more remote. Man
available time will become increasingly restrictive and the inbye workings more difficult to
ventilate.
4.13.7.4
Longer Term Plans
At present the mine has no firm plans beyond the extension of the current working area to the
west. However, Tower Colliery Limited are currently undertaking a strategic review of the
remaining reserve/resources at the mine. It is recognised that the current area is nearing
exhaustion and the feasibility of extending the mine’ s life beyond this time is being examined.
However, it must be borne in mind that access to other seams would represent a major capital
investment and such expenditure would be difficult to substantiate in regard to the current
state of the market.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.13.8
PAGE 208
OPPORTUNITIES FOR FURTHER INVESTMENT
It is important to note that at present a large proportion of Tower’ s production goes to both
the industrial and domestic market sectors. As such this production would be excluded from
Investment Aid being subject to EU Regulations. Over the next few years the proportion of
output to power generation may increase; loss in demand for domestic concessionary fuel.
Potentially this would result in an improved proportion of production being subject to
investment aid under the new scheme should it be implemented. Unfortunately, increased
sales to power generation may well reduce the overall proceeds at the mine and conversely
limit the prospects for the generation of cash at the mine being directed into possible
investment schemes. Therefore it would appear that at present the mine would find it difficult
to support any future major schemes. It is more likely to be faced with the situation of
procuring funds from external sources.
The current working area is reaching exhaustion, production beyond February 2005 being at
significant risk from faulting, steep gradients and seam thinning. The opportunity for
investment in this area is therefore limited, although a proving heading to the north, outbye of
the current faces may be considered. The only major anticipated expenditure is the
refurbishment of roof supports that would be regarded as a Category 1 Project.
Outside the present plans for workings in the Seven Feet/Nine Feet Seam the mine is carrying
out longer-term strategic planning. This work is aimed at examining potential options that
might be available within other seams and accessible by drivages from the present
infrastructure. These feasibility studies need to be completed prior to evolving any potential
investment plans.
The mine is developing a scheme for a Briquetting Plant that will increase proceeds.
Improvements to the methane drainage and utilisation plant are also required. These schemes
could potentially fall into Category 2.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 209
205000
204000
rth Thrust Zone
Projected Tower No
ult
Fa
Tower
Licence Area
Six Feet Resources
ed
ork
w
6ft
Fernhill Slide Area
Six
to s Feet s
out plit
he s
ast
201000
Fernhill S
lide
t
aul
gF
rrw
nco
Gly
Pentreclwydau South
Licence Area
Six Feet Mineral Potential
Si
to x Fe
so et
uth sp
ea lits
st
lt
Fau
ch
wra
mg
Cw
202000
ed
ork
w
6ft
s
igo
Rh
203000
Di
na
sF
au
lt
200000
TOWER LICENCE BOUNDARY
Note: Only old workings from Glyncorrwg Colliery are shown
1000m
0m
Scale
Figure 4-26
I5104C
295000
294000
293000
292000
291000
290000
289000
288000
287000
286000
285000
284000
199000
TOWER COLLIERY
SIX FEET SEAM
RESERVES AND RESOURCES
Tower Colliery: Six Feet Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 210
205000
204000
rth Thrust Zone
Projected Tower No
s
igo
Rh
ult
Fa
203000
Nine Feet
Mineral Potential
Full Nine Feet Seam
residual unworked area
lt
Fau
ch
wra
mg
Cw
202000
t
aul
gF
rrw
nco
Gly
Pentreclwydau South
Licence Area
Nine Feet Mineral Potential
Full Nine Feet
Seam
residual area
between faults
(inaccessible)
Fernhill Slid
e
Di
na
sF
au
lt
201000
Fernhill Slide area
Nine Feet
Mineral Potential
Full Nine Feet Seam/
dependent on structural interpretation
200000
Thru
st Zo
ne fr
om
Seam split to the South (Details unknown)
1980’s
interp
retat
ions
TOWER LICENCE BOUNDARY
Note: Only old workings from Glyncorrwg Colliery are shown
1000m
0m
Scale
Figure 4-27
I5104C
295000
294000
293000
292000
291000
290000
289000
288000
287000
286000
285000
284000
199000
TOWER COLLIERY
NINE FEET SEAM
RESERVES AND RESOURCES
Tower Colliery: Nine Feet Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 211
205000
204000
rth Thrust Zone
Projected Tower No
s
igo
Rh
Motorway Area
Possible Partial
Extraction Area
203000
ult
Fa
lt
Fau
ch
wra
mg
Cw
202000
t
aul
gF
rrw
nco
Gly
)
pth
de
alf r.
x h pilla
o
r
p n
(ap ctio
0m ote
30 pr
ne
Zo
st
u
r
Th
st
We
er
w
To
Area based on
7ft/5ft possible extension
to the south of panels
(further investigation required)
(Mineral Potential)
Lower 7 ft/Upper 5ft
V44
201000
V46
V47’s and V49’s unworked areas
V45
Resources: V46’s, V51’s and V53’s
200000
Reserves: V44’s
Di
na
sF
au
lt
V47
V49
Reserves and Resources: Area
Glyncorrwg Colliery
(Closed)
Shaft Pillar
Reserves: Motorways Area
V51
V53
Tower Licence Boundary
1000m
0m
Scale
Figure 4-28
I5104C
295000
294000
293000
292000
291000
290000
289000
288000
287000
286000
285000
284000
199000
TOWER COLLIERY
SEVEN FEET/FIVE FEET SEAM
RESERVES AND RESOURCES
Tower Colliery: Seven Feet/Five Feet Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 212
TOWER COLLIERY: APPENDIX
TABLES 1 & 2
TOWER TABLE 1: SEAM SEQUENCE, LOWER & MIDDLE COAL MEASURES
MAIN SEAMS
COMMENTS
TYPICAL INTER-SEAM
INTERVAL (m)
(potential reserves/resources seams in BOLD)
Note that lower seams outcrop progressively to the north (and to the south, within the Rhondda Fawr valley); seams of the Four
Feet/Six Feet succession have been extensively opencasted just north of the shaft area. Seams of the Pennant Measures, particularly the
No. 2 Rhondda, are present across the more southerly areas, and have been locally mined in the near-surface.
Gorllwyn
Extensively mined.
55m to 60m
Two Feet Nine
Extensively mined where not split.
12m to 15m
Four Feet
Extensively mined where not split.
25m to 30m
SIX FEET
Locally mined; potential resources.
35m to 40m
NINE FEET
Extensively mined; mineral potential.
15m
Bute
Locally mined; common washouts.
40m to 50m
SEVEN FEET/FIVE FEET
Extensively mined, with remaining reserves
and resources.
Only thin seams (including the Gellideg) are expected below the Seven Feet/Five Feet.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 213
TOWER TABLE 2: RESERVES, RESOURCES, AND MINERAL POTENTIAL (IMC, 2002)
SEAM &
LICENCE
AREA
ZONE/MINING
BLOCK
RESERVES
Net Mt,
see notes
RESOURCES
Net Mt,
see notes
MINERAL
POTENTIAL
Net Mt, see notes
SIX FEET
(Tower)
Unworked areas west of
the seam split/Fernhill
Slide.
-
Not yet
quantifiable, see
Comments.
See comments
SIX FEET
(Pentreclwydau)
Pentreclwydau licence
area.
-
-
9Mt, assuming 75%
deduction from
gross.
Based on:
2.00m coal.
Deduction: 75%
NINE FEET
(Tower)
South of the Main West
Laterals.
-
-
Not yet quantifiable.
-
North of the Main West
Laterals)
-
-
Not yet quantifiable.
-
NINE FEET
(Pentreclwydau)
Pentreclwydau licence
area, north of Northings
200 (seam may be split
to the south).
-
-
7Mt, assuming 75%
deduction from
gross.
Based on:
2.00m coal.
Deduction: 75%
SEVEN/FIVE
FEET
(Tower)
V47’ s, V49’ s
0.8
-
-
Based on:
0.90m – 1.20m coal
Deduction: 5%
V44’ s
0.4
-
-
Based on:
1.20m coal
Deduction: 30%
North of Main W.
Laterals, not yet laid out,
assume two longwalls.
-
0.7draft
-
Based on:
1.20m coal
Deduction: 40%
Nominal layout west of
V44’ s/V49’ s
-
0.6draft
-
Based on:
0.85m coal
Deduction: 60%
Motorways area: partial
extraction
1.4 draft
-
-
Based on:
2.00m coal
Deduction:60%
-
-
Not yet quantifiable.
Potential partial
extraction area c. 2km
south of shaft.
COMMENTS
(see notes)
Quantification will be
largely dependent upon
mining constraints.
-
TOTALS (Reserves & Resources)
Reserves:
Seven Feet/Five Feet
2.6Mt including the partial extraction Motorways area.
Resources:
Seven Feet/Five Feet
1.3Mt
Resources:
Six Feet
(not yet quantifiable.)
NOTES. 1. The thicknesses (centimetres) refer to an expected (reserves) or potential mined section, seam-less-dirt.
2. The deductions refer to an assessment of coal lost through geological and other factors, that are not otherwise discounted
through the mine planning process.
3. The quoted tonnages are net, after applying the above deductions.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 214
SMALL MINES
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.14
ABERPERGWM COLLIERY
4.14.1
BRIEF DESCRIPTION OF SITE
PAGE 215
Aberpergwm is located in the Neath Valley, South Wales near to the villages of Glyn Neath
and Blaengwrach just off the A465 trunk road.
Coal mining in the area of Aberpergwm Colliery has taken place for several centuries,
Quakers working the area immediately to the west of the current mine entries which consist of
two inclined roadways. The mine was closed by British Coal in April 1986, the entries being
sealed and the surface infrastructure demolished. The underground workings were allowed to
flood.
The mine remained closed for 10 years, until April 1996, when Signal Fern Ltd (a subsidiary
of Consolidated Coal plc) re-opened it. The mine was de-watered and ventilation restored. A
systematic recovery of the mine infrastructure was then undertaken.
During the re-development of the mine in the Six Feet (Eighteen Feet) Seam, it had been
intended to work remnant pieces of anthracite to help offset the high costs. Unfortunately, the
‘pillar’ areas that were to have been exploited were found to have been extensively worked by
Quakers, these early workings being unrecorded. Signal Fern went into receivership in
September 1999 and mining temporarily ceased.
The mine was then kept open on a “ care and maintenance” basis until July 2000 when Dragon
Coal Corporation started to work the mine as a sole contractor appointed by Anthracite
Mining Limited (AML), which had been formed in December 1999. The mine remained in
production until December when Dragon Coal Corporation (who subsequently went into
liquidation) left the mine site. Anthracite Mining Limited (AML) took over the operation of
the mine and it recommenced production in January 2001. AML has a surface land holding of
some 200 acres and an option of an area of coal between Aberpergwm and Treforgan.
Surface buildings at the drift site consist of a limited number of ‘portacabin’ type buildings.
There is a coal preparation plant located some 3km south of the mine site at the Rheola Works
which also has substantial undercover stocking facilities. The mine has access to a railhead
with grading facilities (at Pentreclwydau South on the opposite side of the Neath Valley) and
stock pads which is located within 1km of the main mine site.
4.14.2
MINE BOUNDARIES, OTHER SURFACE CONSTRAINTS AND ISSUES
The licence boundary is aligned to abandoned mines, Severn Sisters to the north, Treforgan in
the west, old workings in the east and geological disturbances together with several small
abandoned mines in the south.
4.14.3
4.14.3.1
GEOLOGICAL ASSESSMENT OF THE MINE
Introduction
In this section, the geology of the mine and reserve zones are discussed for Aberpergwm.
Note that the mine is independent of the main producers: geological data and recent
interpretations have not been readily available. This report is therefore relatively wideranging. The following is based partly upon historical documents received from the mine
operators, and partly upon selected data held by the British Geological Survey. Full data
access, and therefore a more definitive account of the geology, is beyond the scope of this
report.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 216
The report text describes the geological setting of the mine and its reserve base. It is
supported by Appendix tables, summarising the seam sequence, geological data for the Six
Feet and Nine Feet seams, and reserves.
The mine is in the western half of the South Wales Coalfield. The drift entrances dip
northwesterly from the western side of the valley, south of Glynneath. Other now-closed drift
mines lie close by, notably Pentreclwydau, just to the southwest. (Note: the 1990’ s
Pentreclwydau South drift mine lies on the opposite side of the Neath Valley, the drivages
extending southeasterly.) The succession is typical for South Wales: Lower and Middle Coal
Measures, with many seams, are overlain by Upper (Pennant) Coal Measures, dominated by
sandstones with fewer and thinner seams. All coals are anthracite. Table 1 summarises the
main seam sequence.
There are no overlying Permian or later solid formations. There are no significant igneous
features. Superficial deposits, and local landslip material, overlie the Coal Measures in places.
Some areas have been opencasted. The cover to surface increases to the west, under the high,
largely forested ground between the Neath and Dulais valleys. A wide area of interest extends
between these valleys, incorporating resources that were accessed by the NCB’ s Treforgan
Colliery, in the Dulais Valley. Present production is from the Six Feet Seam (locally known
as the Eighteen Feet).
4.14.3.2
Structure and Landslips
The mine lies just northwest of a large geological feature, the SW-NE Neath Disturbance.
This complex fault zone is a major boundary between mines on the two sides of the Neath
Valley. Aberpergwm Colliery is sufficiently distant from this, and none of the faults in the
mine area are directly assigned to the Neath Disturbance.
The Coal Measures are disturbed by both “ cross faults” , essentially normal in style, and
numerous compressional structures (thrusts, some large, with associated folds). The interval
variations of Table 1 partly reflect these structural disurbances.
•
Cross faults typically strike NNW-ESE, with throws between <10m and >100m. Larger
cross faults have similar dispositions throughout the Coal Measures.
•
Thrusts and folds commonly strike NW-SE, and have a much greater density in the Lower
and Middle Coal Measures.
•
The thrusts and folds tend to be compartmentalised by the larger cross faults, each intercross fault area having its own density of compressional structures. Thrust deformation
tends to increase where the distance between cross faults is reducing.
•
Following from this, attention is drawn to an extensive area, centred on Treforgan No. 4
Borehole, where there is likely to be 2km or more ground between significant NNW-SSE
normal faults. The only proving here is the borehole, which records significantly fewer
faults than other Treforgan and Dulais Valley boreholes.
•
Regarding practical mining in thrust areas, NCB reports suggest that seams in which
thrusts tend to be discrete, rather than in wide belts, are more suitable. An NCB report
dated 1983 further suggested that the Red Seam and perhaps the Four Feet, both in the
area east of the Pentreclwydau Fault between Aberpergwm and Onllwyn workings, were
the most likely reserve zones to test this.
Landslips occur at many elevations on valley sides, and were formally catalogued by the
Institute of Geological Sciences (now British Geological Survey: South Wales Coalfield
Landslip Survey 1980). Updating is probably required. The main features are on the lower
southeast-facing side of the Neath Valley, southwest of Aberpergwm, and on higher ground
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 217
between Aberpergwm and the Neath-Dulais watershed. The landslip areas, and associated
crag instabilities, would require detailed desk studies prior to mine design. Landslip 40
(related to large crags, at c. E283000/N206400), and its smaller neighbours, is in an area of
Nine Feet Seam interest. Layout limitations related to landslips applied to possible re-opening
of Pentreclwydau in 1989. Note that other surface instabilities, not formally catalogued, are
also present, for example where forestry access roads have been made across topographical
spurs.
4.14.3.3
Reserve Seams
Introduction
The mine’ s only present reserves seam is the Six Feet, in a restricted area close to the
Aberpergwm access. However, the operators consider that a wider area, particularly in the
Nine Feet, could be accessed from Aberpergwm, possibly with a connection through to the
(presently closed) Treforgan drivages from the Dulais Valley. IMC is advised that land
ownership is established, and that the Treforgan entrances are expected to be technically
recoverable; a definitive view on this is beyond the present scope. The operators have also
considered other entries into the wider resources, especially south into the Nine Feet from the
outcrop near Onllwyn, and northwest into the Six Feet just north along the Neath Valley from
Aberpergwm.
Appraisals since 1983 have been limited to the Four Feet, Six Feet, Red, Nine Feet and Bute
seams. Only the Six Feet (mainly within the present mining area) and the Nine Feet are
consistently thick enough for the present mining system, and only the Nine Feet is relevant to
the wider area between Aberpergwm and Treforgan. Development into this area will therefore
depend upon geological variations in the Nine Feet. Tables 2 and 3 summarise seam data for
the main seams. Tables 4, 5 and 6 summarise recent reserves appraisals, including (Table 6)
IMC’ s present evaluation. The following seams are noted on the mine’ s Five Year
Development Plan (No. 2, ref. DTI-DEH-5000). Geological variations in the key seams are
now summarised.
Four Feet Seam
On the Development Plan, this is included pictorially as Coal 1.30m. The seam was worked to
c.1km down-dip from the eastern outcrop, the NCB identifying further reserves west to the
Pentreclwydau Fault, in 1983 (Zone “ A” ). These workings included longwall units. Seam
analyses nearby recorded thickness ranges from 0.91m to 1.14m, ash (seam-less-dirt) 3.4% to
4.3%, and sulphur 0.8%. It is assumed that the seam would have similar thickness and quality
in the remnant Zone “ A” . The seam splits to the west, and the thicker coalbed of the Four Feet
group is only 1.00m thick, and commonly <0.6m thick, in most of the Treforgan and Dulais
Valley boreholes. It is concluded that the only area of interest would be east of the
Pentreclwydau Fault. In this area, the workability of the seam would be very variable, because
of extensive and thick extractions in the underlying Six Feet and Nine Feet seams.
Six Feet Seam (present production seam, locally known as Eighteen Feet)
Introduction. This seam has been extensively worked at Aberpergwm, and from
neighbouring mines/entries. These include Pentreclwydau, Penstar and Ladysmith, (Neath
Valley) and mines along the northern outcrop northwest from Glynneath. In Aberpergwm
itself, workings have extended west of the Pentreclwydau Fault: the 1983 NCB reserve plan
showed a residual reserve zone (“ C” ) there, west to a seam split (see below). Table 3
summarises seam data from key provings.
Roof. The roof is thought to be a reasonably competent mudstone over most of the present
mine area. Top coal is not normally left for support, and the very weak “ rashings” which
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 218
characterise the roof on the southeast side of the Neath Valley (Pentreclwydau South) are only
rarely relevant to mine workings, according to the operator. In the wider area, some sandstone
roof is expected (for example, see Treforgan 4 and 6 boreholes), with the potential for local
seam washouts.
Seam. At Aberpergwm, the Six Feet is known as the Eighteen Feet, in recognition of its
significant thickening, which is very local. It is the prime seam of the upper Neath Valley, in
terms both of thickness and quality. The seam thickness partly reflects original deposition,
and partly thickening through thrust deformation. The seam is reported as generally less prone
to shear deformation, compared with Pentreclwydau South. However, the seam splits rapidly
west of Aberpergwm, and is not relevant to reserves or resources in the wider Aberpergwm –
Treforgan area, except perhaps locally towards Seven Sisters (in the north: this mine worked
both main coalbeds of the Six Feet, individually). It is thought that the western limit of the
earlier NCB workings approximated to the incoming Six Feet split, and planned workings in
the mine (west of the Pentreclwydau Fault) are also likely to encounter it, see later. In the
earlier workings, NCB analyses indicate that seam-less-dirt ash is typically 3% to 6%, with
sulphur around 0.75%. In the boreholes, the seam is typically 3.5% to 9.0% ash (seam-lessdirt) and between 0.80% and 1.00% sulphur.
Floor. The floor is typically mudstone and siltstone seatearth, reported to be sufficiently
strong for free steered vehicles in the mine.
Red (= Caerau) Seam
On the Development Plan, this is shown pictorially as 1.12m thick, coal with cannel. The
seam was worked east of the Pentreclwydau Fault at Aberpergwm (longwall units), further
north at Onllwyn (longwalls), and extensively at Seven Sisters to the northwest. On the 1983
NCB reserve plan, Zones “ B” and “ C” lay east of the Pentreclwydau Fault, between
Aberpergwm and Onllwyn workings. In Aberpergwm workings, the seam was typically
1.10m to 1.50m thick, with some inferior coal and/or cannel at the base and top. The seam
was thicker at Onllwyn. In the drifts through the Pentreclwydau Fault from Aberpergwm, the
seam had thinned to 0.78m.
East of the Pentreclwydau Fault, any new working of the seam would be variable, reflecting
extensive extractions in the Six Feet and Nine Feet. To the west of the Pentreclwydau Fault,
the seam is known to be split, with the lower coalbed typically <1.00m thick, with the upper
coalbed <1.00m, and is locally eroded.
Nine Feet Seam
Introduction. This seam has been extensively worked from mines in the Neath Valley,
including Aberpergwm and Pentreclwydau, and along the northern outcrop northwest from
Glynneath. It has been effectively mined out east of the Pentreclwydau Fault, and around
Seven Sisters. The 1983 NCB reserve plan showed a residual area at Aberpergwm (Zone “ A” )
between the Pentreclwydau Fault and Seven Sisters workings, the main part of the unworked
area to the west being assigned to Treforgan. Table 4 summarises seam data from key
locations. Prior to the mine’ s previous closure by the NCB, Aberpergwm was longwallmining the Nine Feet.
Roof (of the Upper Nine Feet). This appears rather variable across the AberpergwmTreforgan area. There are local thick sandstones in the near-roof, which would require
detailed mapping prior to any development. A local sandstone roof with washouts was
recorded on the Aberpergwm N.2 longwall unit in the 1980’ s.
Seam. The seam is united in parts of the Aberpergwm/Treforgan area, but widely split in
several borehole provings. Seam deterioration and splitting is defined through the worked
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 219
areas north from Pentreclwydau to Seven Sisters, but detailed mapping of the seam split,
including all existing mining and outcrop data, would be necessary prior to any major
investment. The seam is probably united, and 2.00m to 3.00m thick, over much of the
immediate Aberpergwm area, plus those parts of the wider area just to the west (Treforgan
boreholes 4 and 5). Where the Nine Feet is split into the Upper and Lower Nine Feet seams,
both of these coalbeds are very locally >2.00m thick. Thickness varies with structural
deformation. Seam-less-dirt ash ranges between 4% and 7%, away from seam splitting.
Sulphur (seam-less-dirt) is typically 0.75% to 1.00%.
Floor. The floor is typically weak sheared mudstones.
Bute Seam
On the mine’ s Development Plan, the Bute (Peacock) is shown pictorially as 1.10m coal. The
Bute was worked more extensively than the Nine Feet at several local mines, presumably for
quality considerations, but there are no readily available details. At Aberpergwm, there are
large unworked areas where the seam is expected to be around 1.00m thick. However,
workability would be variable, reflecting the proximity of extensive workings in the Nine
Feet. In the Treforgan boreholes, the seam is typically 0.90m to 1.00m thick.
Cover Issues: All Seams
The only significant issue relates to old workings, an assessment of which is beyond the scope
of this exercise. Workings in the Six Feet Seam are known to intersect uncharted/other older
workings: these do not seem to be a significant problem. However, any new mining proposal
should be accompanied by a desk study on potential old workings that might contain water in
quantity. It should also be noted that some of the larger cross faults could transmit water from
higher levels, particularly if placed in tension by mining.
4.14.3.4
Reserve/Resource Assessment
Aberpergwm has limited geographical scope, but relatively large potential resources. These
are difficult to quantify; the following comments apply.
•
For the purposes of this exercise, all the area between Aberpergwm and Treforgan is
assessed, although not all is licensed to the present Aberpergwm operators.
•
Six Feet, present mining area. Multiple horizon extractions are possible in thicker areas,
but conservative evaluations are recommended, assuming only one extraction in any one
location.
•
The mining system uses drivages 3.50m high, which are mainly in coal, within the present
workings. Due to the method of work, it is therefore appropriate to limit reserves to seams
of a minimum thickness of >2.00m over significant areas. This should allow drivage
flexibility where minor disturbances are met. It is also considered appropriate to limit
resources to seams with a minimum thickness of 1.50m. These minima reduce the
reserve/resource seams to the Six Feet and Nine Feet, any other seams contributing only to
mineral potential.
•
Changes in working methods would affect the categorisation of reserves and resources.
For example, it may be that longer-term working could involve shortwall faces, and it is
considered that these would necessitate a minimum height of 1.50m.
The mine operators have access to two relatively recent evaluations done in 1992 and 2001.
The following notes (see also Tables 4, 5, and 6) summarise the two existing reserve/resource
studies, and IMC’ s evaluation.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 220
Comments on the Reserve/Resource Tables
The following comments summarise IMC’ s interpretation of the existing assessments.
•
1992 assessment. This is not considered a sufficiently rigorous assessment, in terms of
data, interpretation, and quantification; the study was very generalised (not even
specifying if the quoted tonnage totals were gross, or net after allowing for layout or
geological considerations).
•
2001 assessment. The 2001 study was comprehensive, including all seams with a
minimum thickness of 1m; deductions of 20% and 30% were applied, to allow for
“ geological loss” , and the net tonnages appear to have been based upon room-and-pillar
extractions, with some allowance for secondary pillar extraction. This assessment is
considered to have been largely speculative beyond the Six Feet proposals. In particular,
the deductions for “ geological loss” are unrealistic at only 20% to 30%, even in the Nine
Feet, because of structural uncertainties; inclusion of the Bute by auger mining is also
considered unrealistic.
IMC’ s assessment of the individual reserve panels (Six Feet) and other reserve/resource areas
are as follows (Table 6 summarises these, with quantifications).
Six Feet: Reserve Panels and Areas
•
Residual area east of E285000, south of N207000. This area is essentially worked out.
•
South Companion Road district (centred c. E284800/N206200): re-entry into a previously
worked district. No significant geological problems are anticipated, although minor
disturbances are known.
•
Room and pillar Panel 181. This lies between the Pentreclwydau Fault and a parallel,
west-downthrowing normal fault (throw c. 12m on the mine plan). This panel is shown
extending north from the Main Intake and Return drivages which, it is understood, would
be re-established for any long-term development into the Nine Feet to the west.
Obviously, the detailed siting of Six Feet workings hereabouts would need to protect these
main drivages. Geological difficulties are expected, as the records of the main drivages
note a series of faults between the Pentreclwydau Fault, and the “ 12m” fault noted above.
These may not be large; the panel’ s northern limit is worked across in the Six Feet,
without significant faults being recorded.
•
Panel 182. This lies west of a fault, parallel to the Pentreclwydau Fault, that is projected
south from the Main Intake and Return drivages. A NW-SE striking thrust is known in the
nearby Nine Feet workings, and some discount should be made to the tonnage
calculations, to allow for some geological disturbance.
•
Panels 183 and 184, west of the Pentreclwydau Fault, adjacent to the Main Intake and
Return drivages. Nine Feet workings, hereabouts, recorded NW-SE striking thrusts, which
are expected to have their equivalents in the Six Feet. Some tonnage loss should be built
into the reserve assessment.
•
Panel 185 is at high risk of fault disturbance:
1. It lies immediately west of the Pentreclwydau Fault, with a risk of associated faults
and seam bedding dip variations;
2. An array of NW-SE thrusts is known, from Nine Feet workings, and from the Main
Intake and Return drivages.
•
Panels north from 184/185. These proposed workings extend northwesterly, parallel to the
overall Pentreclwydau faulted zone. Some structural coverage is available from the N2’ s
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 221
longwall unit worked in the Nine Feet; however, small thrusts known in the Nine Feet
workings west of N2’ s are expected to have their equivalents in the Six Feet area. The
area immediately NNW of Panel 184 is expected to be affected by the incoming Six Feet
seam split, and old workings in the neighbourhood record thickening dirt. Details are
uncertain, but on present evidence, the western third of the area should probably be
discounted for thickening dirt. The mining plan shows the North Intake and North Return
being driven progressively to the NNW. At present, the final cut-off for evaluation is
taken to be Northings 208, as the seam section north of this may deteriorate with the incoming split in the Six Feet Seam. For this exercise, the reserves are taken to the inbye
limit of the N. 2 longwall unit worked in the Nine Feet.
•
Area centred on E284000/N206500: this is a part-worked area; some thrusts are known
from the previous workings, but these do not appear to have inhibited extractions. This
area is not identified for extraction on the present mining plan, but IMC considers that it
could be included as reserves.
Beyond the Six Feet reserve panels.
The Resources identified by this study are in the Six Feet, to the southwest of existing
workings, in the Nine Feet in the area of present and recent Six Feet workings, and in the
Nine Feet to the west (the Hirfynydd block, see earlier).
•
Area southwest of Aberpergwm/northwest of Pentreclwydau (c. E283500/N206500). This
unworked area, defined as extending west to the Six Feet seam split, is considered suitable
for inclusion as resources.
•
Nine Feet: a large resources area is considered to lie west of Aberpergwm, in the
Hirfynydd (Treforgan No. 4) borehole area, see discussion on Structure, above. For
present evaluation, it is considered suitable to define this by Eastings and Northings, see
Table 6.
•
Further resources are considered to lie between this block and the Six Feet mining area,
but these have not been quantified (see Table 6).
None of the Resources, particularly in the Nine Feet to the west, are sufficiently well-proved
for realistic mine planning, and would require modern desk studies, with significant
exploration, see next.
4.14.3.5
Exploration
Exploration, other than by mine drivages, is not appropriate to present workings or plans in
the Six Feet, but longer-term plans would require significant investment in exploration, and
re-establishment of closed facilities. Regarding exploration:
•
Nine Feet. An exploration programme should be preceded by a detailed desk study on
existing structural data from all sources. (Although the NCB 1980’ s maps are reasonably
based for the time, understandings of local structural geology, and of interpretations of
faults in boreholes, have developed.) A number of boreholes, sited following a desk study,
would be required to complement the Treforgan No. 4 hole in the “ Hirfynydd” block.
These would further investigate the seam splitting, the potential for sandstone in the roof
(relevant to seam washouts), and the incidence of faults. The sequence between the Four
Feet and Bute should be cored. Seismic surveys should be considered, although much of
the high ground is forested, and costs would be high.
•
Re-establishment of existing entries (especially Treforgan), and newly planned accesses
(e.g. from the northern outcrop) would also require detailed desk studies, with follow-up
exploration (probably selected drilling) if appropriate.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.14.3.6
PAGE 222
Geological and Reserve/Resource Conclusions
The following conclusions are drawn.
•
Six Feet, working and laid-out areas. The immediate working areas are considered
reasonably secure, and reserves can be readily assessed. However, the planned workings
adjacent to, and west of the Pentreclwydau Fault are expected to have varied geological
difficulties, notably normal faults parallel to this main structure, and (generally small)
thrusts that are known locally in the Nine Feet. The split in the Six Feet Seam is expected
to become significant in the more westerly areas, restricting flexibility in the working
horizon (although some extractions <3.5m height should be locally achievable). It is also
possible that the “ rashings” , apparently little problem in the present workings, could
become more prominent in the roof, west of the Pentreclwydau Fault. Overall, it is
concluded that geological risk will increase significantly, to the west of this fault. All
panels are considered to constitute Reserves, but with variable geological risk.
•
Six Feet, beyond the laid-out areas. An area of part-worked Six Feet, southwest of present
workings, is available. There may be further (unworked) Six Feet to the west of this, to
the seam split limit. The mine operator has not formally identified these areas on the
present mining plan.
•
Nine Feet, Aberpergwm. There are residual areas of united Nine Feet that could feature in
a reserves assessment, but these have not been identified by the mine operator, and are
therefore not considered here.
•
Nine Feet: wider area. The main area of interest is in the “ Hirfynydd” block, west of the
present accessible area, and entry into this would require significant exploration and
investment. This block is considered suitable for Resources. Beyond this block, the
remaining Nine Feet is considered Mineral Potential.
•
Other seams. Possible areas of interest in the Four Feet, Red, and Bute are considered to
have only Mineral Potential value.
The following table summarises Table 6 of this section which is shown along with the plans
and other tables at the end of this section on Aberpergwm Colliery:
Table 4-74
IMC Re-assessment of Aberpergwm Reserve/Resource: Summary
(01/12/02)
Million Tonnes
Seam
Six Feet (Eighteen Feet)
Nine Feet
Total
Reserve
Resource
Total
Mineral Potential
0.48
0.20
0.68
Possible (not quantified)
-
3.60
3.60
Possible (not quantified)
0.48
3.80
4.28
-
Note: some reserve and resource areas have not been quantified.
A more detailed geological assessment, beyond the scope of this report, would probably result
in substantially increasing the category of resources and highlighting areas of coal covered by
mineral potential.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.14.4
4.14.4.1
PAGE 223
MINE CHARACTERISTICS AND CONSTRAINTS
Infrastructure
The mine is accessed via two inclined roadways (Drifts) from the surface. The main intake
drift dips at 1 in 3 and the return drift at 1 in 8. The mine infrastructure that is currently being
recovered and restored was originally driven by British Coal and is quite extensive. The mine
having been abandoned and closed by British Coal in 1986 had been sealed off and allowed to
flood. Having been re-opened in 1996 a succession of operators moving in a westerly
direction has progressively re-established the infrastructure by a combination of de-watering,
roadway repair and new drivage.
The roadways are supported by steel arches of various size and design, ranging from 12’ x 10’
to 18’ x 12’ . The mine is currently working in an area some 1,800m to the west of the mine
entries and continues to advance west. Where the original roadways were driven in crossmeasure their main fabric has in general found to be in good condition, with only minor
repairs necessary. However, where the roadways were in seam, conditions have varied
greatly and some major repairs have been necessary with the setting of new arches and the
ripping out of the old. In some, more geologically disturbed areas, it has been found
impracticably to repair the old roadways and new roadways have been driven adjacent to
those existing. This has resulted in a fairly complex network of roadways, that in general are
standing well, however, there are some areas which have been affected by movement due to
geological disturbance and the volume of old workings in their close proximity.
4.14.4.2
Layouts
The mine has traditionally extracted coal by partial extraction, driving roadways leaving
narrow pillars. The uncertain geology including a high incident of thrust faulting results in
variable and weak roof conditions, this necessitates the need to use passive steel supports.
The layout of the current working consists of extracting remnant pillars of coal by driving
roadways in them utilising either roadheaders or boring and firing and loading out with Eimco
mechanical shovels. In some areas of thrust faulting the seam has been found to thicken to
over 6.0m. In these areas large arches have been set and then arch leg extensions fitted as the
floor is subsequently removed.
4.14.4.3
Roadways Conditions
As described above, the main infrastructure roadways that have been recovered to date is
generally in reasonable condition, albeit that there are areas in high-stressed zones that are
subject to deformation. In the working areas where remnant pillars are being extracted
conditions vary and in all instances the arches are subject to distortion and cannot be
withdrawn for future use once the working area has become exhausted.
4.14.4.4
Coal Clearance
Coal clearance is by belt conveyor. 36” belting is normally used mounted on 42” structure.
Capacity ratings have not been supplied, but the system is capable of transporting the
relatively modest outputs that are currently produced and planned.
4.14.4.5
Manriding and Materials Transport
There are currently no manriding facilities. Men walk to and from the workplace directly
from the surface via the return drift.
Materials transport is by diesel powered free steered vehicle, which travel directly from the
surface materials compound into the mine via the return drift.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.14.4.6
PAGE 224
Other Services
The mine has compressed air, water pumping and electrical supplies. Methane drainage is not
practised.
4.14.4.7
Ventilation
The mine has two surface drifts, the intake dip at 1 in 3 and contains the forcing ventilation
fans (two Woods 48JS-D200/40 single stage axial flow fans in parallel). Roadway cross
section is quite small being some 6–9m2; airflow available within the intake drift is
approximately 53m3/sec. The forcing system was adopted to keep the mine pressurised to
reduce the effect of the gas in the old mine workings as the mine was recovered. The return
drift (main transport roadway) is inclined down at a gradient of 1 in 8.
The problems of working remnant coal, is that from time to time old workings are breached,
some of which are not recorded. This can cause sudden emissions of gas, which can be
methane or blackdamp (oxygen deficient atmosphere). Whilst a forcing system reduces the
effect on personnel working within the drivage that connects with the old roadways/workings
it can still cause problems within the mine. As the area contacted has connections back into
the mine at some point, this allows this displaced mine gas to emerge elsewhere, probably
unnoticed initially.
Considerable work is required on the main infrastructure to reduce the pressure losses within
the ventilation system particularly as there will be a requirement to increase airflows
significantly when accessing reserves through the Pentreclwydau Fault.
Ventilation network calculations that were completed December 1998 will at some point need
to be re-assessed due to the probable changes in the mining plan.
4.14.4.8
Subsidence
The main subsidence constraint is that from landslips. A detailed assessment of the risk is
required, particularity those that may be reactivated, taking into account proposed areas of
working, depth of cover and methods of working.
Six Feet Seam
The Six Feet Seam is to be worked by a partial extraction system, which will cause smaller
amounts of subsidence than would be expected from longwall working. The areas considered
for mining are under woodland, with a number of streams.
It may be difficult to plan any mining in areas 1 (Panel 181), 2 (South Companion Drivage
area), 3a (Panel 182) which would not have an effect on known landslips. Area 5 (SW
District) and 6 (SW District Reserves) also include landslips but some mining will be possible
in these areas which does not affect stability.
In the absence of landslip re-activation, subsidence damage costs would be negligible. The
mine operation, however, will need to demonstrate (to the Coal Authority) that mining will
not disturb existing landslips. It is possible that the level of bonding required may preclude
viable mining in some areas.
Nine Feet Seam
These reserves lie under a mixture of wooded and hill farming areas. The south-west part is
free from known landslips, they occur over the remainder of the area. It should be possible to
carry out extensive mining avoiding landslips.
Subsidence damage costs will be low unless a landslip occurs.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.14.4.9
PAGE 225
Coal Preparation Facilities
The plant is a 200t/h handling / 100t/h washing module, and was commissioned in 1997.
Around 60% of the ROM is extracted as dry fines with the remaining 40% being washed. If
the need arises the potential plant capacity is around 10,000t/w equating to 0.48Mt/a.
ROM exits the drift and is transferred to road transport and taken to a railhead disposal point
at Pentreclwydau South. Here the ROM is dry screened, with the aid of mobile plant onto a
storage pad. The oversize is then transported by road to the Rheola Works site, stored
undercover and batch processed as and when stock permits a sensible operational period
(bearing in mind the mine is producing between 1,200t/w and1,500t/w). The feed to the plant
is via a hopper with a controllable outlet feeding a 100t/h Dense Medium Drum via a pre-wet
screen. The drum reclaims a cleaned coal fraction, which is classified in various sizes to suit a
domestic and on site retail market. The undersize from the pre-wet is pumped to a pair of
slurry cyclones. The coarse fraction together with the undersize from the classifying screens is
fed to a dewatering centrifuge, this either added to the PSF blend as required with the balance
if any being sold to the briquetting market. Fines from the cyclones are recovered in a small
clarifier, the top water is re-used in the process, and the recovered sludge is dewatered and
added to the discard for disposal system.
The mine is currently producing a medium grade of anthracite from a ROM feed varying
between 1,200 and 2,500t/w. Current vend is between 80% and 85% with a ratio of domestic
to PSF around 20:75
Stocking facilities at Pentreclwydau are around 7,000 tonnes with a further 15,000 tonnes at
the Rheola Works which can also hold around 10,000 tonnes of domestic grades, all under
cover at the works.
All of the domestic grades are re-screened before sale. Apart from bulk domestic sales and the
provision of concessionary coal, there is a pre-packed fuel retail facility on the Rheola site.
4.14.5
4.14.5.1
HISTORIC PERFORMANCE
Production
Table 4-75
Historical Production Performance at Aberpergwm
Aberpergwm
1999
2000
2001
2002
(estimated)
Actual Output
million tonnes – saleable
0.052
0.015
0.043
0.057
Budgeted Output
million tonnes - saleable
N/A
N/A
0.072
0.076
Difference
million tonnes - saleable
N/A
N/A
-0.029
-0.019
The mine was held in a period of ‘care and maintenance’ from September 1999 to June 2000,
Signal Fern, the company who had re-opened the mine in 1996, having gone into
receivership. Production in 2001 and 2002 has been restricted by the difficulties that have
been encountered in re-opening and restoring the mine infrastructure to the west. Output has
been confined to extracting very limited pillars to the east of the Pentreclwydau fault.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.14.6
PAGE 226
FUTURE MINING PROJECTION
The strategy is to continue to concentrate output within the Six Feet and extend the
infrastructure roadways to the west at the earliest opportunity by a combination of roadway
recovery and new drivage. It is intended to extend into the reserves west of the
Pentreclwydau Fault. However, it is believed that a relatively substantial pillar is available
just to the east of the fault zone. The exploitation of this area is crucial to maintaining output
during 2003.
Contractors are being utilised to assist in the development of the main infrastructure. In 2002
the contractors installed an LH1300 heading machine in the Main A5 Return and are
demonstrating a long-term commitment to the mine. It is intended that the contractors will
also supplement the mine’ s workforce in the exploitation of the pillar and stall units, possibly
providing dint header machines to maximise production.
The geological nature of the seam does not lend itself to longwall mining and it has been
traditionally worked by partial extraction using various pillar and stall methods. The strategy
takes cognisance of this and a semi mechanised pillar and stall system is planned using diesel
powered load haul dumps for initial mineral clearance. Roof bolting has also been included
within the plans. However, if this proves unsuccessful then given suitable geological
conditions roof support may be able to be salvaged for re-use to minimise materials costs.
Longer-term secondary partial pillar extraction has been included within the plans with the
possible use of an auger.
With the establishment of the semi-mechanised room and pillar systems in previously
unworked areas coupled with secondary partial pillar extraction, it is intended to raise annual
output to around 280,000 tonnes by 2004. This is mainly as the result of the involvement of
contractors who are provisioning dint heading machines for the production stalls. It is also
intended to maximise large coal production to diversify markets and enhance proceeds.
4.14.7
4.14.7.1
PRODUCTION AND DEVELOPMENT FORECASTS
Production
Production in 2001 and 2002 has been badly affected by the difficulties in extending the
infrastructure to the west and the inability to maintain production from the small pillars of
coal left to the east a thrust fault north of the Main Intake. The mine has received Operational
Aid through this period.
The extension of the main infrastructure through this thrust fault is complete and a circuit has
now been established to provide a platform for exploiting remaining coal that lies to the east
of the Pentreclwydau Fault.
The bulk of the production for the immediate future will come from the development of the
main intake and return utilising the LH1300 and Dosco Mk2A heading machines. These will
be supplemented by a pillar and stall team exploiting thick remnant pillar coal close to the
thrust fault.
Production is expected to rise to around 12,000 tonnes per month, as the
heading machines become established in areas free of old roadways.
Production in 2003 will be mainly concentrated in the pillar area between the thrust fault and
the Pentreclwydau Fault. Zones are available both to the north and south of the main access
roads. Contractors are to concentrate on expanding north into the main pillar whilst AML’ s
own production teams extract remnant pillars to the south. Output is projected to be around
150,000 tonnes. The introduction of additional Dosco Dint Headers to further mechanise the
pillar and stall system will greatly enhance the ability to achieve the planned levels of
production.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 227
Production is planned to increase further during 2004 with the introduction of secondary
partial pillar extraction by auger or other means. The ability to safely introduce the partial
removal of the pillars will be dependent on finding the best pillar size and direction of work to
establish optimum roof control. Good geological conditions will be essential. The
introduction of partial pillar extraction will also give the advantage of maximising recovery of
reserves.
In the longer term when accessing virgin areas consideration is being given to the possible
introduction of single entry shortwall panels.
4.14.7.2
Development
The key to success of the development programme is to access replacement virgin reserves
that lie west of the current working area. The Main West Intake has been extended through
the thrust fault area. The works were much more difficult than anticipated and have taken
significantly longer than planned.
The West Return has been extended by deviating back into the old road, re-ripping forward
and then turning and grading back out, before thirling into the inbye cross cut that has been
formed from the Main West Intake.
The Main Return (A5) has been repaired to its forward position and contractors have installed
an LH1300 Heading Machine. This will have some cross-measure drivage to do before being
re-established in-seam.
It is now intended to develop the infrastructure within the area between the thrust fault and the
Pentreclwydau Fault utilising the LH1300 (AMCO) and a Dosco Mk2A (AML) before
reclaiming the Main West Intake and Return Roadways west through the Pentreclwydau
Fault. The bulk of the roadways through the fault are in cross-measures and from past
experience it is expected that these roadways should, for the main part, be in reasonable
condition.
4.14.7.3
Risk
The continued development of the mine to the west relies on the refurbishment of old
roadways, the conditions of which are unknown. Roof control problems may occur with
cavities forming and as demonstrated by the difficulties experienced during the recent past
progress may be inhibited threatening continuity of production.
The immediate working area is located adjacent to and between the Pentreclwydau Fault and
the thrust fault and is consequently at risk from faulting. However, the adoption of pillar and
stall techniques will give some flexibility in negotiating faulting.
Most future workings are in virgin areas and are therefore more at risk from faulting. As
stated above the proposed method of work provides mining flexibility.
In the short term, production will continue to be limited, and costs relatively high. The mine
has already experienced problems in maintaining financial support. The main concern and
issue therefore is whether AML can continue to adequately finance the immediate period until
they have fully established production in their new working area at the beginning of 2003.
4.14.7.4
Longer Term Plans
Longer term plans are likely to be based on short term development proving viable areas of
coal. Favourable results from proving viable areas of coal would then facilitate changes in the
production strategy. This could involve the assessment of the following:
•
Continuation of the blocking out of areas of thick coal
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 228
•
Operating coal headings utilising load haul dump methods
•
Multi-entry headings driven using waffler chains (undercutting machines) and bore / fire
methods
•
The introduction of roof bolting as the primary means of support
•
The introduction of shortwall faces
4.14.8
OPPORTUNITIES FOR FURTHER INVESTMENT
With relatively simple access available to a new seam within an unproven area of ground, this
mine has a project that would qualify under the proposed scheme. However, IMC understand
that cash is extremely restricted at present. In addition, this mine also has restrictions on its
overall grant benefit due to the lower level of qualifying coal from the mine.
Future profits are planned on an almost unprecedented increase in output that drives down
cost of production. There are some potential partners to become involved in the scheme.
There is hope for a major scheme to build a power station combined with the underground
developments and there is a possibility that either mining contractors and/or equipment
manufacturers could participate in a joint venture. The realisation of these ideas will depend
upon the overall stability of the company. Unfortunately as previously stated cash is severely
restricted at present, as is general throughout the coal industry.
All of these problems are over and above the general risks associated with mining.
The mine is recovering the old infrastructure and progressively developing west. It is
intended to access and prove some secure areas of coal. Once such areas have been
established then there could be potential for generating schemes to improve extraction
techniques as previously described. There is also potential for the capitalisation of strategic
proving headings.
I5104C
IMC GROUP CONSULTING LIMITED
4
NORTH
INTAKE
AND
RETURN
DISTRICT
5
L 18
ANE
3a P
207000
Pr
ov
ed
)
(P
oo
rly
SE
AM
FE
ET
SI
X
IN
SP
LI
T
TREFORGAN WORKINGS TO WEST
NINE FEET SEAM
RESOURCES AREA
("HIRFYNYDD BLOCK")
1
PANEL
181
3a
PANEL 182
6
SW DISTRICT
(RESOURCES)
2
SOUTH
COMPANION
ROAD AREA
(PART WORKED)
T
AUL
AU F
WYD
ECL
NTR
H/PE
BAC
LAU
PWL
206000
SIX FEET
WORKINGS
(Generalised)
3b
PANELS
183/184
5
SW DISTRICT
(PART WORKED)
286000
285000
SEVEN SISTERS
WORKINGS
284000
283000
PAGE 229
282000
281000
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PENTRECLWYDAU
COLLIERY
PENSTAR
ABERPERGWM
COLLIERY
H
AT
NE
EY
LL
A
V
500m
0m
Scale
205000
Anthracite Mining Limited
ABERPERGWM COLLIERY
SIX FEET (EIGHTEEN FEET) AND NINE FEET SEAMS
RESERVES AND RESOURCES
December 2002
(Note: Most worked areas not shown for clarity)
Figure 4-29
I5104C
Aberpergwm Colliery: Six Feet and Nine Feet Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 230
ABERPERGWM COLLIERY: APPENDIX
TABLES 1-6
ABERPERGWM TABLE 1: SEAM SEQUENCE
(generalised, from Treforgan & Dulais Valley boreholes)
MAIN SEAMS OF THE LOWER & MIDDLE COAL
LOCAL
MEASURES: STANDARD NAMES (Key seams in BOLD)
NAMES
Note: generally thin seams above the Four Feet.
White
FOUR FEET
SIX FEET
Eighteen Feet
CAERAU (= RED)
Red, Cornish
Lower Red
Harnlo
NINE FEET
Nine Feet
BUTE
Peacock; Yard
Yard
Lower Peacock
Lower Seven Feet
Upper Bluers
Upper Five Feet
Lower Bluers
Lower Five Feet
Rhyd
Upper Gellideg
Grey
Lower Gellideg
Lower Gellideg
Typical inter-seam intervals
(see section on Structure)
15m to 25m
10m to 25m
5m to 15m
5m to 25m
10m to 25m
20m to 30m
20m to 25m
10m to 20m
15m to 20m
<10m
10m to 15m
50m to 60m
Garw
I5104C
Cnapiog
Seams below the Garw are expected to be very thin.
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
Borehole
or Seam
Report.
Aberpergwm
6
Dulais
Valley 1
Dulais
Valley 2
Pentreclwydau
5
Pentreclwydau
6
Seven
Sisters
No. 1
Shaft
Treforgan 1
Treforgan 2
Treforgan 3
Treforgan 4
Treforgan 5
Treforgan 6
Ynisarwed
PAGE 231
ABERPERGWM TABLE 2: SIX FEET (= EIGHTEEN FEET) SEAM
SELECTED LOCATIONS
Easting
Northing
Splits and
Thicknesses (cm)
Ash
s-l-d %
Sulphur
s-l-d %
Rank
CRC
Roof
(U6Ft)
Floor
(L6Ft)
Notes
285294
205895
Coal 330
Mudstone
(<3m +)
Seatearth
280237
206633
279670
205275
283979
205904
Six Feet widely split:
Upper 6Ft = c+d 97
C 69 (U6Ft)
Mudstone
Seatearth
Mudstone
Seatearth
Coal 335
c. 3.5m to
sandstone
Seatearth
>3m
283689
205613
Coal 444
c. 1.5m to
sandstone
Seatearth
United seam.
C 99 (U6Ft)
D+c 213
C 38 (L6Ft)
Mudstone
Mudstone
Seatearth
U6Ft – L6Ft c.
17m.
c. 5m to
sandstone
Mudstone &
siltstone
Sandstone
close above
Mudstone
Seatearth
281253
207419
279480
207894
279902
206962
281807
206722
280741
205506
280516
207125
282355
203087
5.7
0.98
100
C56 (U6Ft)
3.5
0.87
Coal + dirt 112 (U6Ft)
14.1
0.91
Vols.
6.6%
101
Coal = dirt 72 (U6Ft)
8.9
0.81
102
C 49 (U6Ft)
13.2
0.79
C + d 90 (U6Ft)
6.5
1.02
Vols.
7.2%
102
Seatearth
Seatearth
Seatearth
Coal 86 with c+d 9cm
above (total =U6Ft)
4.9
0.97
102
Sandstone
Seatearth
(clean
(clean
coal)
coal)
Treforgan underground boreholes not accessed (mainly Nine Feet succession)
Obscure: thick, united
seam.
U6Ft – L6Ft c.
18m
U6Ft – L6Ft c.
18m split
United seam.
U6Ft – L6Ft 18m
split.
U6Ft – L6Ft c.
16m split
U6Ft – L6Ft c.
19m split
U6Ft-L6Ft c. 17m
split
ABERPERGWM TABLE 3: TREFORGAN SURFACE BOREHOLES: NINE FEET SEAM
Borehole
or Seam
Report.
Treforgan
1
Treforgan
2
Easting
Northing
Treforgan
3
279902
206962
Treforgan
4
281807
206722
Treforgan
5
280741
205506
Treforgan
6
280516
207125
I5104C
281253
207419
279480
207894
Splits and
Thicknesses (cm)
Ash
s-l-d %
Sulphur
s-l-d %
Rank
CRC
Roof
(U9Ft)
Floor
(U9Ft)
Notes
Seam splitting into Upper and Lower Nine Feet seams; section partly sheared.
C
20)
Dirt
17)U9
Coal
108)Ft*
Inferior c + dirt 78)
C 144)
Dirt 3) Upper 9 Ft
C 92)
Full Nine Feet Seam:
Inferior c + dirt 127
C
44
D
5
C
44
Inferior c + dirt 44
C, minor dirt 248*
Dirt & coal
43
Full Nine Feet Seam:
Coal & dirt
56
Dirt
106
Coal
293*
U. Nine Feet Seam:
Coal 207 (top 6
inferior)
9.0 (clean
coal)
0.78 (clean
coal)
102
Mudstones,
faulted
Mudstone
& sheared
seatearth
*Disturbed
section
4.1
0.78
101
Mudstones
& siltstones
Seatearth,
soft
Disturbed
and sheared
*Main
bed: 10.9
*Main bed:
0.89
102
Sandstone
close above
seam.
Floor of
L9Ft: Mudstone
seatearth.
*Main
bed: 11.9
*Main bed:
1.06
102
Sandstone
close above.
6.6
0.76
102
Mudstones
Floor of L.
9Ft:
mudstone
seatearth
Seatearth,
sheared.
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 232
ABERPERGWM TABLE 4: RESERVES ASSESSMENT 1992
Tonnage Assessed (Mt)
Comments
SEAM
Not
assessed
Four Feet
Not
assessed
Six Feet
Not
assessed
Red (Caerau)
Estimated c. 15Mt
Five blocks of coal, A-E, were assessed, between Pentreclwydau
Nine Feet
Bute
SEAM
Four Feet
Six Feet
Estimated c. 7Mt
ABERPERGWM TABLE 5 : RESERVES ASSESSMENT 2001
Red (Caerau)
Nine Feet
Bute
I5104C
workings west to the Treforgan drivages, as follows.
A: a central zone centred on Treforgan 4.
B: just NW of the old Pentreclwydau workings.
C: NW from Treforgan 1 and 6 boreholes.
D: a southerly zone between Pentreclwydau and Ynisarwed
(Neath Valley).
E: a southwestern zone between Treforgan 5 and Dulais Valley
No. 1 boreholes.
Note, there is no guidance as to whether the quoted tonnages
were gross (“ in place” ), or net following risk assessment.
These resources are thought to have been in the same zones as
described above for the Nine Feet, but no map is available.
Again, it is uncertain whether the tonnages were gross, or net.
Zones
Tonnages/mining method (tonnages are “ROM”)
Aberpergwm A*
0.58Mt, based on auger extraction.
Aberpergwm A*
Aberpergwm B*
Aberpergwm C*
Aberpergwm D*
Aberpergwm A*
0.67Mt, based on auger extraction.
0.69Mt, based on auger extraction.
1.10Mt, based on room-and-pillar extraction.
0.35Mt, based on room-and-pillar extraction.
0.62Mt, based on auger extraction.
Aberpergwm A*
Treforgan A*
Treforgan B*
Treforgan C*
Treforgan 1*
Treforgan 2*
Treforgan 3*
Aberpergwm A*
Treforgan A-E*
*NB: the available report does not
include a map showing zone location.
Total, 11.79Mt, based mainly on room-and-pillar
extraction (Treforgan 1 & 2 auger zones).
Note: Treforgan 1, 2 & 3: Lower Nine Feet only.
Total 3.16Mt, based on auger mining.
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 233
ABERPERGWM TABLE 6: RESERVES/RESOURCES ASSESSMENT 2002 (this study)
Zone/location
Outline tonnages/Comments
SEAM
East
of
the
Pentreclwydau
Fault
only.
Possible
mineral
potential; not quantified.
Four Feet
Zone
1.
East
of
the
Pentreclwydau
Fault:
panel
181.
Reserves.
Est.
net
tonnage c. 0.05Mt
Six Feet
Zone 2. East of the Pentreclwydau Fault: part-worked
“ South Companion Road” area, centred c. E284800
N206200.
Zone 3 a-c. West of the Pentreclwydau Fault: panels
182 to 185.
Zone 4. West of the Pentreclwydau Fault: North Intake
& Return panels, north to inbye limit of N. 2 (Nine
Feet) and west to the seam split. (Note also: seam
section risk beyond Northings 208.)
Zone 5. West of the Pentreclwydau Fault, part-worked
area SW of the NW Intake & Return drivages, centred
on E. 284000 N. 206500.
Zone 6. West of the Pentreclwydau Fault, southwest of
Aberpergwm/northwest of Pentreclwydau, c. E.283500
N. 206500.
Red (Caerau)
Nine Feet
Re-entry in Penstar area
East of the Pentreclwydau Fault only.
“Hirfynydd” block: provisionally de-fined by
Eastings 281 to 283, Northings 205 to 207.
Residual areas east of Eastings 283, accessible from
Six Feet workings.
Other areas, west of Eastings 281, south of Northings
205, and north of Northings 207.
All areas.
Bute
Reserves. Est. net tonnage c. 0.05Mt
Reserves. Est. net tonnage c. 0.18Mt
Reserves. Est. net tonnage c. 0.14Mt
Reserves. Est. net tonnage c. 0.06Mt (not identified on
present mining plan)
Resources, assuming a united Six Feet Seam, or with
an acceptable dirt thickness, giving a working section
comparable to present districts. Assessed at 0.20Mt,
area gross discounted at 75%.
Not assessed: speculative only.
Possible mineral potential; not quantified.
Resource area. Based on a potentially less-disturbed
structural block, within which the Nine Feet Seam is
expected to be mainly a united seam.
•
Potential working thickness: 2.5m coal saleable.
•
Net tonnage (75% deduction on area gross) of
3.6Mt.
Resource areas. Based on a united Nine Feet Seam, or
with an acceptable dirt thickness. Unquantified, subject
to mining evaluation.
Not assessed: speculative only at this stage. Assumes
re-establishment of the Treforgan entries and drivages.
Not assessed: highly speculative at this stage.
TOTALS
Reserves: (estimated)
Six Feet
0.48Mt minimum (see notes below)
Resources:
Six Feet
Nine Feet
NOTES.:
1.
2.
3.
4.
I5104C
0.20Mt
3.60Mt
(at 75% discount on gross).
(at 75% discount on gross), plus unquantified
tonnages adjacent to Six Feet reserve areas.
Only one extracted height assumed, with 3.00m coal, all districts.
Pillar and stall extraction: assumed at c.25m pillar centre spacings throughout.
Coal in some development roadways has not been included.
There is obviously considerable potential for local pillar extraction prior to final mine
abandonment; these possibilities are not covered by this assessment.
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.15
BETWS COLLIERY
4.15.1
BRIEF DESCRIPTION OF SITE
PAGE 234
Betws is a modern drift mine that is situated on the slopes of the Betws Mountain above the
town of Ammanford in Carmarthenshire, South Wales. The mine site has ready access to the
A474 and A483 main roads, the latter of which connects directly to Junction 49 of the M4
Motorway that is only some 8km distant.
The main mine entries consist of two drifts some 3,200m long dipping at an average gradient
of 1 in 7 and were developed by British Coal in the 1970’ s to exploit the Red Vein seam,
enabling production to commence in 1978.
The mine ceased operations in early 1993 and was kept on a period of ‘care and maintenance’
until May 1994 when it was purchased on a lease/licence agreement by a management buyout
by the present owners, Betws Anthracite Limited.
4.15.2
MINE BOUNDARIES, OTHER SURFACE CONSTRAINTS AND ISSUES
The mine is bounded by old workings from adjacent closed collieries and major fault
structures. The mine works beneath in a rural area beneath a mountainside and is not
constrained by surface features.
4.15.3
GEOLOGICAL ASSESSMENT OF THE MINE
4.15.3.1
Introduction
In this section the general and more detailed geology of the mine and reserve zones are
discussed for Betws. The mine’ s overall resources, including the seams described below, are
not thought to have been assessed (other than for privatisation purposes) since the 1980’ s, the
mine having been working only limited areas, by partial extraction, since then. This report is
therefore relatively wide-ranging, and five tables (Betws Appendix) supplement the text:
•
Table 1: seam sequence.
•
Tables 2 and 3: summaries of key geological data for the main seams.
•
Table 4: summaries of changes in reserve/resource assessments
•
Table 5: summary of IMC’ s reserve/resource assessment, 2002.
Betws lies on the northwest margin of the South Wales Coalfield, southeast of Ammanford.
The mine entrances are in the Amman Valley, the surface access drifts extending southeast
beneath the rising ground of Mynydd Betws. The succession is typical for South Wales:
Lower and Middle Coal Measures, characterised by many seams, are overlain by the Upper
(Pennant) Coal Measures, which are dominated by sandstones with fewer, and generally
thinner seams. All coal seams are of anthracite rank. There are no overlying Permian or later
solid geological formations. Superficial deposits are present throughout much of the area; peat
is common on the higher ground. There are no major cover problems; probable water-bearing
sandstones, brought closer to reserve seams adjacent to large faults, are noted later. There are
no igneous features of mining significance. Table 1 summarises the seam sequence.
4.15.4
STRUCTURE AND LANDSLIPS
The Coal Measures are disturbed by thrust faults, which have a characteristically greater
density in the main seam sequence (especially between the Six Feet and Bute seams) than in
higher seams. The key disturbances are large NNW-SSE normal fault zones, particularly the
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 235
Betws Fault to the west, and the Gardeners Fault to the east, with throws around 200m and
300m respectively. There are some small normal faults, typically striking N-S. The Coal
Measures dip southerly. The cover to surface increases rapidly south, beneath Mynydd Betws.
A mapped landslip (LG22F, on the high ground in the south of the area) is relevant to the
reserves. This is small; monitoring is planned, and no problems are anticipated. A full
appraisal of surface geological features is beyond the scope of this report.
4.15.4.1
Reserves Seams
Introduction
The mine, divided west and east by the Gardeners Fault, was originally developed to exploit
the Red Vein in the western area. Subsequent developments east through the Gardeners Fault
were originally to access the Upper Nine Feet and Bute seams, the plans being changed to
work the Four Feet. Tables 2 and 3, below, summarise key seam data for the Four Feet and
Upper Nine Feet seams. Tables 4 and 5 summarise progressive changes in reserves
assessments, and IMC’ s views on the reserve base. The following seams are considered to
contribute to the reserves and resources.
•
Red Vein (western block). Note that most of the 1980’ s reserves are not relevant; these lie
at considerable depth to the south, are thin, and now inaccessible.
•
Four Feet (present workings/reserves, eastern block; possible areas in western block)
•
Upper Nine Feet (eastern block)
Note that the Bute Seam (eastern block) may contribute to resources, following any access
into the Upper Nine Feet. At present, it is poorly proved, but could be explored by
underground boreholes from the Upper Nine Feet. In this report, the Bute is considered as
having mineral potential, see later. Note also that there may be a combined Five
Feet/Gellideg Seam in the eastern block (suggested by Abernant No. 8 Borehole
[E270752/N206540] to the southeast). The seam has not been considered for reserve purposes
by Betws Anthracite Ltd, and is not discussed further; the data is inadequate for mapping.
Red Vein
The remaining area, for partial extraction, is adjacent to the main drivages and would be the
final reserve for the mine.
Roof. The roof is variable, with common thin sandstones.
Seam. There are two seam splits within the Red Vein. The residual partial extraction reserves
are in a thicker, unsplit area, wherein a seam section is likely to approximate to:
Coal 0.45, Dirt <0.15, Coal 0.40, Dirt c. 0.15, Coal 0.50
This gives a total around 1.60m. Seam-less-dirt ash is expected to be around 6.0%, and seamless-dirt sulphur around 1.0%.
Floor. The immediate floor is typically mudstone seatearth, with stronger material a variable
depth below. The stronger beds usually lie below a thin floor coal.
Red Vein: Cover. There are no anticipated cover problems. Underground water ponds in
earlier Red Vein workings are known, and noted on the mining plan.
Four Feet Seam
Present production is by partial extraction in the eastern block. Table 2 summarises key data.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 236
Roof. The roof is typically “ competent” , with local weaknesses from flat-lying plant remains
and local large ironstone concretions. These weaknesses give only occasional problems on the
partial extraction system. Some of the borehole logs in the eastern reserves suggest that the
sequence between the Four Feet and the overlying minor seam (the Stwrin) may include a
small channel sandstone belt, but the data is too scattered to allow mapping. No washouts of
the Four Feet are known in the eastern block.
Seam. The seam deteriorates and thins northeast towards the outcrop, but Betws 15 Borehole
proves continuity of the seam’ s mining value to the northern limit of planned extraction. The
seam is typically between 1.10m and 1.60m thick. Seam-less-dirt ash varies between 3.5%
and 6.0%; seam-less-dirt sulphur varies between 0.75% and 0.90%.
Floor. The floor is typically soft to 0.60m below the seam, with stronger material beneath.
Cover. There are no significant problems. Water ponds in earlier Four Feet workings are
known, and noted on the mining plan. Various significant beds of sandstone (Llynfi Rock
succession, above the Red Vein) are brought close to the Four Feet by the Gardeners Fault,
and it is understood that this will be catered for, when planning workings close to this fault.
Upper Nine Feet Seam (= Big Seam, as named locally).
Access into the Upper Nine Feet, in the eastern block, is being actively considered. Table 3
summarises key data.
Roof. The roof is mudstone, with some siltstones and thin sandstones above, in the limited
provings. Shearing, with local minor thrust repeats of parts of the seam, is also noted.
Seam. Seam thickness is expected to be between 1.20m and 2.00m over most of the area and
is likely therefore to be thicker overall than the Four Feet. A definitive thickness trend cannot
be established, because the seam is affected by minor thrust deformation at some of the
boreholes. However, the Upper Nine Feet can be considered for partial extraction reserves
evaluation. Seam-less-dirt ash varies between 4.0% and 9.3% (the higher figures probably
reflecting minor dirts introduced by thrust repeats); seam-less-dirt sulphur varies between
0.70% and 0.80%.
Floor. This is mudstone seatearth in all relevant borehole provings. It is commonly sheared.
Cover. The cover issues will be similar to those of the Four Feet (q.v.).
Bute Seam
This seam lies some 40m to 50m below the Upper Nine Feet. There are no present mining
intentions, and the Bute has not been investigated in any detail for this exercise. It is likely to
have a quality and rank similar to the Four Feet and Upper Nine Feet seams (the sulphur
content may be higher). Its thickness in the following eastern block boreholes is as follows:
Abernant No.9, coal 1.10m; Betws No.13, coal 1.03m; Betws No.14, 1.01m; and Betws
No.15, coal 1.18m. At Betws No.12, correlation is necessary to establish the seam horizon.
The roof is typically mudstone, and the floor includes stronger siltstones and sandstones.
4.15.4.2
Reserve/Resource Assessment
Reserve Areas: Overview of Geological and Related Risk
Given that seam continuity (in terms of thickness, splitting, quality attributes and rank) for the
Four Feet and Upper Nine Feet seams are established in the eastern block, the main concerns
regarding geological risk are (typically small) thrust faults in the Four Feet, and especially in
the Upper Nine Feet. The existing Four Feet workings have proved a generally favourable
structural environment, which is likely to continue through much of the identified reserve
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 237
area. However, this structural continuity is less secure for the Upper Nine Feet given that it
has yet to be developed.
•
There are no modern mine workings in the neighbourhood, to give local experience.
However, it has been worked extensively in the past at adjacent collieries in the 1920’ s
and 1940’ s.
•
The seam is known, from regional evidence, and from the local boreholes, to be in that
part of the succession that is more prone to small thrust faults.
•
These thrusts are likely to have low bedding dips, and extrapolation even from the Four
Feet would be difficult.
The later section on Exploration discusses geological risk reduction. For the present exercise,
it is considered that the Upper Nine Feet remains a valid seam for inclusion in a reserves/
resources statement, but the tonnages require some reductions from those assessed simply
from the idealised partial extraction layout.
Assessment
The last full NCB/British Coal assessments (available to IMC) of both the western and eastern
blocks are dated 1984 (modified in 1987) and 1990. Also, Betws Anthracite Ltd. has made an
assessment of the eastern reserves/resources in the Four Feet and Upper Nine Feet (Big)
seams, dated November 2002.
•
The reserves statement of 1984/1987 included Red Vein reserves (and resources expressed
as “ Unclassified Reserves” ) south to c.1km depth (estimated from the outcrop of the
Graigola Seam, see Table 1) in the western block, and an area of (Upper) Nine Feet and
Bute in the eastern block.
•
The reserves statement of 1990 showed only one panel (S5’ s) in the Red Vein reserves,
some reserves in the eastern block Four Feet, and no reserves/resources in the Upper Nine
Feet or Bute seams.
•
The mine operator’ s 2002 assessment comprises Four Feet and Upper Nine Feet (Big)
tonnages for the eastern block, and recognises that only one small area of Red Vein
remains on the western side, prior to final withdrawal of eastern access and mine closure.
Table 4 summarises main changes between assessments. These are interpreted as follows.
•
In the mid 1980’ s, the mine was extracting > 0.5Mt of Red Vein annually, with peak
production of c. 0.7Mt, accounting for c. 3.0Mt changes in Red Vein reserves to 1990.
•
By 1990, it was evident that the more southerly Red Vein reserves/resources were
unlikely to be economic, mainly because of working a thinner seam at increasing depths.
•
The eastern side Nine Feet and Bute proposals were discounted in favour of the Four Feet,
which was deemed to have a more secure structural environment.
IMC’ s comments on these changes, and on the November 2002 assessments, are as follows.
•
The reduction in Red Vein tonnages has been compatible with extraction (mainly pre1990) combined with the inevitable discounting of the southern zones.
•
The continuing inclusion of Four Feet reserves reflects:
1
The access infrastructure already in place before privatisation;
2
The successful implementation of the partial extraction system (as developed in the
Red Vein);
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
3
PAGE 238
The generally favourable geological environment of the Four Feet Seam.
•
It is accepted that the re-inclusion of the Upper Nine Feet (Big) Seam is logical, inasmuch
as the seam is technically accessible c. 65m below the Four Feet, and seam continuity,
acceptable thickness and quality have been proved by the key boreholes. However, it must
be recognised that the Upper Nine Feet may have a more disturbed geological
environment than the Four Feet (see section on Exploration, later) but this will only be
substantiated by further development.
•
The 2002 Four Feet tonnages are based upon the mining plan for the Four Feet dated
September 2002. The partial extraction panels north of the Lower East Return are laid out
to take account of faults where possible. It is noted that an existing Four Feet panel has
worked to within 70m of the Gardeners Fault (the limit was determined by the conveyor
system). It is also noted that the present working district (F.14) is subject to minor faults
(and the adjacent Betws No.13 Borehole may record a c. 10m normal fault, some 42m
below the seam). South of the Lower East Intake, the layout is more idealised, as existing
workings are less extensive, and fewer faults are therefore known.
•
The 2002 tonnage estimates, see Table 4, require some discounting for geological
uncertainties. The mine seems typically to extract c. 40% of the partial extraction panel
areas (as gross plan areas) but this varies between c. 75% (F.1 district) to probably c. 30%
on the present F.14 district. For the Four Feet, a generalised 50% discount (on panel
gross) is recommended, whereas 60% is recommended for the Upper Nine Feet on present
evidence. Red Vein tonnage estimates probably require only nominal discounting, if any.
Table 5 re-states the operator’ s 2002 assessment, and includes IMC’ s assessment of the
identified reserves/resources, including the suggested discounts for geological risk. It also
summarises IMC’ s view of other areas, not formally assessed by the operator.
4.15.4.3
Exploration
Recent workings in the Four Feet Seam have, from the operator’ s point of view, cast some
doubt on the value of earlier surface seismic surveys, although the last surveys were
undertaken in the 1980’ s, and techniques have improved. It is possible that modern reprocessing of the 1980’ s lines could enhance structural understanding. However, seismic
surveys (surface and in-seam) are more suitable for imaging steep normal faults (which are
thought to be rare, based on present Four Feet workings, and extensive over-working in the
Red Vein), rather than thrusts. Overall, the partial extraction system is relatively flexible with
respect to unexpected faults, and large-scale surface seismic surveys may be inappropriate.
Regarding the Upper Nine Feet, the density of expected small, but significant thrust
disturbances can not be assessed from Four Feet workings. The most suitable form of
exploration for the Upper Nine Feet would be a series of underground boreholes (drilled also
to intersect the Bute, below the Upper Nine Feet). A sufficient number of these would confirm
seam thickness trends, and allow some early estimate of any significant thrusts between the
Four Feet, Upper Nine Feet, and Bute seams. It might also be possible to undertake
underground seismic reflection surveys looking down from the main Four Feet and access
drivages. Such a survey was undertaken in the 1980’ s at Abernant, just southeast of Betws,
the resulting images benefiting from the reduced distance to target seams, and the elimination
of near-surface problems.
Surface boreholes would be very expensive, the cost of each being many times that of an
underground hole, with a resulting very low data density.
Exploration recommendations are summarised as follows.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 239
•
Seismic surveys. The possibilities of re-processing the 1980’ s 2D seismic surveys
should be considered, particularly with respect to identification of thrusts in the Nine
Feet and Bute succession.
•
Existing borehole logs. A modern structural analysis (desk study) of these holes would
be cheap and particularly valuable if the 1980'
s seismic were re-processed.
•
Upper Nine Feet and Bute seams. A series of inexpensive underground boreholes,
from the Four Feet workings, is strongly recommended, see discussion above. Some
of these could usefully extend to the Gellideg, to investigate any regional extent of the
thick seam proved at Abernant No. 8 Borehole.
4.15.4.4
Geological and Reserve/Resource Conclusions
The following conclusions are drawn.
•
The partial extraction system in both the Red Vein (western block, residual panel) and
the Four Feet (eastern block) is established, and the remaining areas are valid
Reserves. Some discounting of quoted tonnages (Four Feet) is necessary, for
geological risk.
•
The partial extraction system is also expected to be valid for the Upper Nine Feet, the
identified area constituting Resources. Some discounting (which should be greater
than that for the Four Feet) is necessary, for geological risk.
•
There is scope for extending the Four Feet assessment, particularly to the south and
east of the presently defined area, see Table 5.
•
At present, there is no potential, realistic extension to Upper Nine Feet reserves.
•
The Bute is considered to provide Mineral Potential only.
The following table summarises Table 5 of this section below
Table 4-76
IMC Summary Re-assessment of Betws Reserve/Resource: (01/12/02)
Million Tonnes
Seam
Reserve
Resource
Total
Mineral Potential
Red Vein
0.25
-
0.25
Possible (not
quantified)
Four Feet
0.32
Not
quantified
0.32
-
-
1.40
1.40
-
0.57
1.40
1.97
-
Upper Nine Feet (Big)
Total
4.15.5
4.15.5.1
MINE CHARACTERISTICS AND CONSTRAINTS
Infrastructure
The mine has a large and well-maintained infrastructure. The main intake and return drifts
are 3,200m long and dip at a gradient of 1 in 7. Two further 1,000m long Drifts rising at
about 1 in 15 access the Four Feet seam to the east of the Gardners Fault. The roadways are
supported by 17’ x 12’ steel arches.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.15.5.2
PAGE 240
Layouts
Production is from hand-filled stalls, a traditional method of mining that has been extensively
used throughout the anthracite mines of South Wales. 5m wide roadways are driven in-seam
for about 80m, and then retreated back by breasting out on one side. The headings are bored
and fired and then loaded out by hand onto mini chain conveyors.
The stalls are accessed by a number of roadways that are driven off the main infrastructure
roadways, both to the north and south. These roadways, which are also driven by hand, are
generally restricted to around 500m in length by the auxiliary ventilation. These roadways are
driven at about 7’ 0” high and supported by props and bars. Floor dirt has to be excavated to
make the additional height.
4.15.5.3
Roadways and face conditions
Main infrastructure roadways are generally in very good condition. The district access roads
are also generally satisfactory. The seam has a strong roof, however, it is prone to floor lift
that can restrict the operations within the stalls, limiting the amount of coal that can be
extracted by widening and retreating back.
4.15.5.4
Manriding and materials transport
The main return drift has a major rope haulage system that is complete with manriding
carriages and facilities. Rope haulages are used throughout for the transportation of materials.
Inbye manriding is by means of a double-deck manriding conveyor installed in the Four Feet
Intake Drift.
4.15.5.5
Ventilation
Four fans for the mine are constructed into a bulkhead in the fan drift, which produces
sufficient ventilation to ventilate the main infrastructure roadways. There are two surface
drifts, the main intake and conveyor road and the main return and manrider roadway.
These roadways provide a down dip access and connections through the large Gardeners fault
provide access to the Four Feet Seam. These connections are some 3000m from the adit
entrance and passing through the connection to the Red Vein Seam, which has been worked
out and sealed.
The coal in the main working areas is worked by drilling and firing and loading out by hand.
These are all auxiliary ventilated and there is sufficient ventilation within the main circuits to
satisfy the fan requirements. There is also sufficient ventilation to develop the Upper Nine
Feet Seam below the Four Feet Seam.
4.15.5.6
Subsidence
Four Feet Seam
Very few buildings exist in this area but a few streams will be affected by mining. The F8
development, in which mining has started under-works a small landslip area. Mining is by a
partial extraction method, which should result in smaller amounts of subsidence than for
longwall working, nevertheless, landslip re-activation must be considered a possibility until a
study demonstrates otherwise.
Subsidence damage costs will be negligible unless landslip occurs.
Upper Nine Feet Seam (Big Seam)
It is also planned to work this seam by a partial extraction method. As for the Four Feet Seam
area, few buildings would be affected by mining in this seam. The landslip area, which is
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 241
undermined by the Four Feet Seam, will also be affected by mining in the areas of B10 and
B11.
Subsidence damage cost will be negligible unless landslip occurs.
Red Vein
Mining in this seam will work under farmland on a hilltop. The only features of any
significance is the Penlle’ s Castel which is a Roman earthworks. This may be an ancient
monument but damage as a result of mining would be most unlikely. A power line crosses
the area of proposed mining but again, damage is unlikely. There are no known landslips in
the area.
Subsidence damage costs are likely to be negligible.
4.15.5.7
Coal Preparation Facilities
The present day coal preparation facilities at Betws, consists of a Large Coal Washing plant
incorporating dry fines extraction, commissioned in 1991. To this a Dense Medium Cyclone
plant was added in 1994, giving a washing capacity of 160t/h. The potential plant capacity is
around 16,000t/w equating to 0.77Mt/a.
The mine produces around 2000t/w, which is far less than the potential capacity of the
preparation plant. ROM comes to the surface in batches of around 200 tonnes from an
underground storage bunker. ROM exits the drift feeding into a 20 tonne surge hopper with
overspill facilities to ground, there is a ground stock recovery system in place via the surge
hopper; this allows the plant around 4hrs continuous processing per day.
From the surge hopper the feed is extracted at a controlled rate feeding to a dry fines/scalping
screen. The undersize can either be diverted to a stock or fed to the DM Cyclone Plant. The
intermediate fraction represents the feed to the DM Drum Plant with the screen oversize being
hand-picked with the coal crushed and fed back to the screen feed. The large coal DM plant is
a two-product unit, coal and discard. The cleaned coal produced is classified to suit the market
requirements and stocked in loading bays. Prior to despatch it is wet-screened to provide top
quality products. The discard is sent to the tip.
The fines from both the pre-wet and the classifying screen are recovered in a spiral classifier
and put to stock. When drained sufficiently it is added to the feed to the DM Cyclone section.
The overflow from the clarifier is pumped to a small clarifier, the overflow, cleaned water is
reused as process water, and the thickened underflow from the clarifier is dewatered on a
Multi Roll Filter producing a filter cake.
Under normal circumstances the dry fines are fed to a desliming screen, separating at 1mm,
prior to being pumped in a DM Cyclone, this produces a cleaned coal fraction and a discard.
The discard joins the large discard for disposal, the cleaned coal is dewatered in a centrifuge
and ground stocked or bypassed directly to ground as the feedstock for the “ filter media”
plant.
Underflow from the desliming screen is pumped into a slurry cyclone; the recover solids are
initially dewatered on a slurry screen feeding into the centrifuge feed system. The overflow
gravitates into the clarifier associated with the large coal plant.
Because of the quality of the anthracite it has specialised uses other than heating, primarily as
a graded “ filter media” in the water industry. Betws has shown that there has been a
significant increase in this market, which if continued as planned would greatly enhance
proceeds.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.15.6
PAGE 242
HISTORIC PERFORMANCE
4.15.6.1
Production
Table 4-77
Historical Production Performance at Betws
Betws
1999
2000
2001
2002
(estimated)
Actual Output
million tonnes – saleable
0.106
0.066
0.072
0.072
Budgeted Output
million tonnes - saleable
0.114
0.079
0.076
0.072
Difference
million tonnes - saleable
-0.008
-0.015
-0.004
0
Since October 1999 output has been solely from the Four Feet seam. Prior to this production
was concentrated in the Red Vein seam at around 110,000t/a. Output in 2000 dropped to
66,000t, insufficient development having been completed in the Four Feet area to maintain
production at the former level. Efforts through the period have been directed towards fully
establishing the Four Feet area to enable annual output to be raised back to +110,000t. 2002
has been a particularly difficult year for the company, and in spite of interruptions to
production regarding supply of explosives and a short period of non-production whilst
insurance was secured output for the year has met planned expectations.
4.15.7
FUTURE MINING PROJECTION
The strategy for the mine is to continue exploiting the Four Feet Seam reserve with the
emphasis placed on development drivage to fully establish 5 stalls on three shift working.
This will enable output to build back to the former levels of over 100,000t/a. It was
envisaged that this would be achieved by 2002, however, due to a series of problems
including the loss of F6’ s this has now been delayed to 2003.
Present plans are for the Four Feet only. However the mine has outline plans for accessing the
Upper Nine Feet Seam that lies some 65m below the Four Feet Seam. This quality anthracite
could provide replacement capacity when the Four Feet reaches exhaustion. The mine
management has indicated that they are actively reviewing possible methods of access and
their investment costs.
Betws Anthracite report that the proportion of house coal that can be produced from the Four
Feet is higher than that from the Red Vein. The strategy therefore remains to maximise house
coal production improving prospects for financial viability. The varied products that the mine
produces, including the Pura-cite water filter medium, and the higher proceeds that they
command is the key to the mine’ s future viability.
4.15.8
4.15.8.1
PRODUCTION AND DEVELOPMENT FORECASTS
Production
In the period 1995 to 1999 production was maintained at around 110,000t/a, working remnant
Red Vein coal mainly in pillar areas close to the bottom of the Access Drifts. In the late
1990’ s the mine re-opened the infrastructure into the Four Feet Seam to the east of the
Gardeners Fault. In the period October 1998 to October 1999 production was from a
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 243
combination of Red Vein and Four Feet workings. From October 1999 production has been
exclusively from the Four Feet Seam, the Red Vein having reached exhaustion.
Output in 2000 dropped to 67,000 tonnes, insufficient development having been completed in
the Four Feet area to maintain production at the former level. In 2001 output was restricted to
72,450t as the mine recovered its development position. Difficulties continued in 2002 with
the loss of F6’ s development through adverse geology, interruptions to production because of
national problems with explosives and a period of ‘care and maintenance’ whilst replacement
insurance cover was sought. It is anticipated that output for 2002 will therefore also be
restricted to only 72,200 tonnes. Throughout this period the mine has received Operational
Aid.
As noted five stalls are planned to be established in early 2003 and then maintained
throughout the remainder of the five-year plan. This will enable annual production to be
sustained at around 115,000t.
Productivity is planned at 10 tonne per manshift, which is firmly based on historic
performance levels. In recent years stall work has been planned at 1,200t/w (24 men @ 10
tonnes per manshift. From 2003 onwards this increases to 2,240t/w (45 men @ 10 tonnes per
manshift with the establishment of five stalls.
4.15.8.2
Development
Emphasis has been placed on replacement development drivages; 1,299m were completed in
2001 against a plan of 1,262m (+37m). However, F6 development has had to be abandoned
due to interaction that resulted in excessive floor heave. This effectively resulted in 320m of
abortive drivage being completed. The development schedule has therefore been re-planned
and projected drivage increased in 2002 from 1,165m to 1,860m.
F2’ s northern drivage has been developed as planned but with a greater roadway height. This
has improved ventilation, enabling the drivage to be extended further north giving the
opportunity to access two additional working areas, namely F15 and F17. This will enable
production from the northern area to be maximised whilst the south is fully developed.
To cover the loss of F6’ s area, F8’ s development has been brought forward. Similarly as F2’ s
is now extended, F10’ s to the south has been brought forward ensuring that adequate
production areas are opened out whilst the north is being fully developed.
Development manpower had been employed through a sub-contractor, but is now directly
employed by the mine. This has been done to ensure long-term continuity of specialised
labour that gives flexibility between development and production.
4.15.8.3
Risk
Betws Colliery is planned to increase production over a five year period from 72,000t/a to
115,000t/a. All production is from hand filled stalls, a method traditionally employed in
South Wales anthracite collieries. The mining method is flexible and capable of overcoming
minor in-seam faults and anomalies. However the Four Feet Seam is prone to severe
problems associated with floor lift which can constrain both output from the stall workings
and the distance they advance from the main access roads.
The method of work at Betws relies on the use of explosives to prepare the coal before it is
handfilled onto chain conveyors. The supply of suitable mining explosives is becoming
increasingly difficult as suppliers withdraw from a shrinking market. Unless this problem can
be overcome, it poses a very real threat to continued production from small mines.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 244
Insurance premiums have increased to levels that are having a significant impact on overall
production costs. This is an area of concern throughout the independent mine producers.
4.15.8.4
Long Term Plans
The layout plans within the Four Feet Seam would indicate that production could be sustained
at the planned levels until around 2008. However in recognising geological risk IMC have
discounted the tonnages by 50% indicating that the area could reach exhaustion by the end of
2005.
To maintain continuity of production following the depletion of the Four Feet, the mine is
currently looking at the feasibility of accessing and working the Upper Nine Feet Seam.
In addition there are reserves of remnant Red Vein that lie in the proximity of the main access
drifts. These could be exploited as the final working prior to mine closure.
4.15.9
OPPORTUNITIES FOR FURTHER INVESTMENT
Betws suffers from the problem of only qualifying for a grant of about 8%, and this is a
severe limitation for the mine. However, one of their biggest problems is the current cash
situation at the mine. The likelihood of receiving any speculative investment is extremely
remote.
Current operations are barely profitable and recently costs have increased especially due to
insurance cover. Mine management has a scheme to develop into a new seam and this
certainly qualifies under the investment scheme. However, funding for the project is unlikely
to be generated at the mine. The management at the mine have suggested that that an
extension of the current operations scheme would be more beneficial especially since the
mine has, over the years, operated on a revenue basis with no underground activity
capitalised.
Betws is planned to produce around 115,000t/a utilising traditional hand filled stalls. The
methods are low cost and require minimal capital investment.
Present plans are for the continuation of Four Feet only. However the mine has outline plans
for accessing the Upper Nine Feet Seam that lies some 65m below the Four Feet Seam. This
quality anthracite could provide replacement capacity when the Four Feet reaches exhaustion.
The mine management has indicated that they are actively reviewing possible methods of
access and their investment costs. It is anticipated that the cost should be restricted to below
£1M. It is considered that any potential scheme would be Category 2.
It is important to note that Betws supplies niche markets producing industrial, domestic and
water filtration products. It does not supply the power generation and coking markets and
may therefore be excluded from an Investment Aid Scheme under EU Regulations.
Realising the potential for increased outputs in the future could result in a portion of the
additional production being sold into the power generation market. Some 200m of sidings
would require refurbishment to establish a connection to the rail network.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 245
Betws Colliery
N
Red Vein and Four Feet
worked to the North
ift
Dr
ift
Dr
In
ta
ke
Re
tu
rn
NE
NE
ift
Dr
250m
Phasing
F2 SUPPLY DEV A F5 DEV.
210000
Lower East Return
10m
7m
Proposed Drifts
into Big Seam
Underground Water
F6 DEV
F6 DEV
F9 DEV
Surface Borehole No.14
F9 reserves lost due to
3 week lay at the end of July.
37m
Surface Borehole No.12
SOUTHERN
RESERVES
2004
2005
209000
Betws Anthracite Limited
Generalised limit of possible resources
BETWS COLLIERY
RED VEIN AND
FOUR FEET RESERVES
268000
267000
208000
266000
265000
500
Figure 4-30
I5104C
F4 DEV
F7 DEV
Red Vein worked
14m
F8 DEV
8m
35m
F10 DEV
Surface Borehole No.3
8m
F11 DEV
6m
15m
15m
2002
0
F1 G DEV
Lower East Intake
2003
100
F1 RET
270000
Peacock Seam
DEV
F12
269000
Upper Nine Feet (Big) Seam
F14 DEV
F18 DEV
F19 DEV
Upper Soap Seam
Lower Soap Seam
Penny Pieces Seam
Stwrin Seam
Four Feet Seam
Upper Six Feet Seam
Lower Six Feet Seam
Lower Red Seam
Surface Borehole No.13
s
ce
ur
so
re
Graigog Seam
F15 DEV
F17 DEV
F13 DEV
ift
Dr
ke
ta
In
Red Vein
F16 DEV
le
ib
ss
po
of
it
lim
rn
tu
Re
Diagramatic Section
NORTHERN
RESERVES
d
ise
al
er
en
G
E
ZON
AULT
RS F
DNE
GAR
Downcast Shaft
Upper East Intake (closed off)
F1 GATE
211000
F1 SUPPLY
ke
ta
In
rn
tu
Re
Surface Borehole No.15
Betws Colliery: Four Feet Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
268500
268000
267500
04
PT
SE
N
SEPT 02
DE
C0
3
04
SE
PT
03
C
DE
F16 DEV
DEC 02
F15 DEV
AU
G0
4
05
PT
SE
F17 DEV
DE
C0
5
SE
PT
05
2
C0
DE
F14 DEV
F18 DEV
03
PT
SE
Betws Colliery: Four Feet Seam Plan
GARDNERS FAULT ZONE
Figure 4-31
2
G0
AU
JUL 03
210500
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
I5104C
211000
NORTHERN
RESERVES
F13 DEV
F12 DEV
F1 SUPPLY
F2 SUPPLY DEV A
F1 GATE
F5 DEV.
210000
F1 RET
F1 G DEV
Proposed Drifts to
access Big Seam
Lower East Return
Lower East Intake
SOUTHERN
RESERVES
F9 reserves lost due to
3 week lay at the end of July.
F9 DEV
OCT 03
JUN 05
MAY 05
F4 DEV
F19 DEV
F11 DEV
F10 DEV
DEC 04
F8 DEV
DEC 03
F6 DEV
F7 DEV
DEC 04
BETWS COLLIERY
FOUR FEET DISTRICT LAYOUT
209500
RESERVES PLAN
DEC 05
AUG 03
Planned Developments
DEC 05
Stalls Completed
Phasing
DEC 03
DEC 03
2002
2003
2004
2005
JULY 05
APR 05
AUG 03
OCT 03
PAGE 246
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 247
Betws Colliery
Ammanford Colliery
Old Workings in the Big Seam
Abandonment Plan No.SW67
Gellyceidrim Colliery
Old Workings in the Big Seam
Abandonment Plan No.9399B
Raven Colliery
Old Workings in the Big Seam
Abandonment Plan No.11943
Probable Underground Water
Probable Underground Water
Maerdy Colliery
Garnant Colliery
Old Workings in the Big Seam
Old Workings in the Big Seam
Abandonment Plan No.
Abandonment Plan No.
Probable Underground Water
Probable Underground Water
Probable Underground Water
rn
tu
Re
ault
ers F
ardn
the G
Peacock Seam
210000
B8 DEV
B6 DEV
B7 DEV
Surface Borehole No.13
B2 DEV
7m
Carmarthen CC
Planning Permission
C6/149
B3 DEV
B1 DEV
Proposed Drifts
into Big Seam
Lower East Return
10m
B5 DEV
B4 DEV
Intake Lateral
Re
tu
rn
NE
NE
In
ta
ke
of
sition
al Po
ectur
Conj
Upper Nine Feet (Big) Seam
ift
Dr
250m
ift
Dr
ke
ta
In
Red Vein
Upper Soap Seam
Lower Soap Seam
Penny Pieces Seam
Stwrin Seam
Four Feet Seam
Upper Six Feet Seam
Lower Six Feet Seam
Lower Red Seam
B9 DEV
rn
tu
Re
Diagramatic Section
Graigog Seam
Upper East Intake(closed off)
Return Lateral
ift
Dr
Downcast Shaft
Surface Borehole No.15
ult
h Fa
moc
Glyn
ift
Dr
ke
ta
In
211000
N
Underground Water
Lower East Intake
6m
15m
15m
8m
Surface Borehole No.3
B11 DEV
B10 DEV
8m
35m
14m
B12 DEV
37m
Surface Borehole No.12
B13 DEV
B15 DEV
B14 DEV
Swansea/Neath PT
Permission Required
B17 DEV
B16 DEV
209000
Surface Borehole No.14
B19 DEV
Betws Anthracite Limited
Figure 4-32
I5104C
270000
269000
268000
267000
208000
266000
265000
BETWS COLLIERY
UPPER NINE FEET
(BIG) SEAM RESOURCES
Betws Colliery: Upper Nine Feet (Big) Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 248
BETWS COLLIERY: APPENDIX
TABLES 1-5
BETWS TABLE 1: SEAM SEQUENCE
PENNANT
MEASURES
MIDDLE
COAL
MEASURES
LOWER
COAL
MEASURES
Borehole
or Seam
Report.
Abernant 6
Abernant 8
Abernant 9
Ammanford 1
Betws 1 &
2
Betws 7 U
Betws 9 U
Betws 12
Betws 13
Betws 14
Betws 15
I5104C
MAIN SEAMS: STANDARD
LOCAL NAMES
Typical interval (m)
NAMES (key seams in BOLD)
The Graigola Seam, some 1000m above the Red Vein, outcrops across the southern part of the area.
No. 1 Rhondda
Duke
130m
No. 2 Rhondda
Ynisarwed
60m
Upper Pinchin
Upper Pinchin
235m
Red Vein
RED VEIN
260m
Rock Vein; Wigan
FOUR FEET
5m – 15m
Six Feet, various coalbeds
Chester; Little; Green
10m – 30m
Caerau/Red
Ddugaled
10m
Lower Red
Rocket
15m
Big; Stanllyd
UPPER NINE FEET
30m
Lower Nine Feet
Gras Uchaf
10m – 15m
Peacock; Trigloin; Braslyd
BUTE
30m
Yard
Brynlloi; Gwendraeth
30m – 50m
Five Feet
Usually thin seams, un-named
Possibly united (as at Abernant
No. 8 Borehole, just SE of the
Four Feet reserves block).
Trichwart & Pumpquart
GELLIDEG
Only thin seams are expected below the Gellideg.
BETWS TABLE 2: FOUR FEET SEAM, EASTERN RESERVES, KEY DATA
Easting
Northing
268857
207055
270752
206540
269442
207400
264665
212230
267203
210494
267869
211015
267911
211015
267873
209348
267863
210494
268981
209722
268518
211078
Splits and
Thicknesses (cm)
Roof
Floor
Mudstone
Seatearth
C 183
(United seam)
Seatearth
C 170
Channel margin
Seatearth
Mudstone
Mudstone
Presumed
seatearth
Seatearth
Mudstone (3m+)
Seatearth
C + dirt 232 (d = 18)
C
+
dirt
(?thrusted)
Coal 121
Ash
s-l-d
%
Sulphur
s-l-d %
Rank
NCB
CRC
196
C + dirt 91, disturbed.
Coal 137
C + dirt 172 (d = 13)
3.6
0.76
101
Possible channel system
Seatearth
C+d 23
C 79
IC 6
C 34
C 117
4.7
0.81
101
Mudstone/Siltstone
Seatearth
5.8
0.73
101
5.2
0.88
101
Channel system in
higher roof.
Mudstone
Probably
seatearth
Seatearth
C + dirt 1.22 (dirt =
10.5)
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 249
BETWS TABLE 3: UPPER NINE FEET SEAM, EASTERN AREA, KEY DATA
Borehole
or Seam
Report.
Betws 12
Betws 13
Easting
Northing
Splits and
Thicknesses (cm)
Ash
s-l-d %
Sulphur
s-l-d %
267873
209348
267863
210494
C + dirt 102 (dirt =
1)*
Coal + dirt 219 (dirt
= 3) (54 lost, poor
recovery*)**
Coal 121
9.3
0.69
Rank
(NCB
CRC)
101
3.8*
0.81*
101
4.3
0.78
101
3.3% to
5.5%
(recovered
coal)
0.75% to
0.86%
(recovered
coal)
101
Betws 14
268981
209722
Betws 15
268518
211078
Coal 214, mainly
clean, based upon
BRD logs
Roof
Floor
Mudstones
**Mudstones &
seatearth
Mudstones
Seatearth
Mudstones
**Mudstones &
seatearth
Mudstone;
silts 0.22
below
seam
Seatearth
Notes
*Disturbed;
recumbent fold.
**Disturbed
section
Poor recovery
BETWS TABLE 4: CHANGES IN RESERVES AND RESOURCES ASSESSMENTS
SEAM/MINING
BLOCK
1984/1987
(British Coal)
1990
(British Coal)
2002
(Betws
Anthracite Ltd)
0.2Mt*
RED VEIN
(west)
13.8Mt
0.1Mt
FOUR FEET
(east)
2.9Mt
UPPER NINE FEET
(east)
2.2Mt
None
1.5Mt*
BUTE
(east)
1.9Mt
None
None
Comments
1.
2.
1.5Mt
0.6Mt*
3.
1.
2.
3.
1.
2.
3.
1.
2.
3.
1984: 10.6Mt classified as reserves,
remainder resources (“ unclassified” ).
1990: Remaining panel only: other
reserves worked in intervening period, or
discounted (depth, distance etc) in favour
of Four Feet development.
2002: Residual partial extraction area.
1984: 1.2Mt classified as reserves,
remainder unclassified.
1990: 0.8Mt classified as reserves,
remainder unclassified.
2002: 0.6Mt* assessed, partial extraction.
1984: All classed as reserves.
1990: Upper Nine Feet deleted.
2002: 1.5Mt* assessed, partial extraction
1984: All classed as reserves.
1990: Bute deleted.
2002: Not included.
*Note: the tonnages as assessed by Betws Anthracite Ltd do not include any deductions for geological risk.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
SEAM/MINING
BLOCK
RED VEIN
(west: final partial
extraction panel)
RED VEIN
(west: south of the
existing longwall
workings)
PAGE 250
BETWS TABLE 5: IMC’s RESERVE/RESOURCE ASSESSMENT, 2002
2002
(Betws
Anthracite Ltd)
0.25Mt
2002
(IMC
assessment)
0.25 Mt
Reserves
Not assessed
Not assessed;
possible local
future
Mineral
Potential.
Discounted.
RED VEIN
(between the
Gardeners &
Glynmoch faults)
FOUR FEET
(East: Laid out
Areas)
FOUR FEET
(East: beyond the
Laid out Areas)
Not assessed.
Not assessed
Possible
Resources,
not
quantified;
see
Comments.
FOUR FEET
(west)
UPPER NINE
FEET (east; laid
out)
Discounted
Discounted.
1.55Mt
UPPER NINE
FEET (east: beyond
present layouts)
BUTE
(east)
Not assessed
1.40Mt
Resources;
see
Comments.
Not assessed.
Not assessed
Not assessed.
0.64Mt
0.32Mt
Reserves
Comments
Tonnages: see main text, nominal discounting only, for geological risk.
The area south of existing workings was originally in NCB reserves. Some
of this could provide Mineral Potential, depending on practical depth limits
(probably 650m BOD), and the detailed seam splitting pattern, which is not
established. A minimum mined section c.1.2m would be necessary. Any
new access would require de-watering of the older workings.
A triangular area of Red Vein has been considered at the mine, the
Glynmoch Fault having a throw of only c. 25m thereabouts. However, IMC
considers that this area would be very disturbed, and almost certainly
unworkable.
Tonnages: discounting necessary, to reflect geological risk; see main text.
The original NCB proposals for the east block were more extensive than
shown on the present operator’ s plans. On geological grounds, it would be
possible to include extensions to the present planned limits, as follows:
•
South, to 1km south of the Lower East Intake, and possibly beyond to
c. N208500.
•
East to a line from c. E270000 (ahead of the Lower East Intake) to the
eastern limit of the Upper East Intake.
•
There may also be (more local) scope north of the Upper East Intake.
The seam is likely to maintain an acceptable thickness within these limits.
These extensions could be classed as Resources.
There is probably an acceptable seam section west of the Gardeners Fault,
but access would be very difficult and costly.
Tonnages: discounting necessary, to reflect geological risk; see main text.
It may be possible to extend the laid-out area to the south and east, but this
would be subject to new exploration, probably by underground drilling
from the Four Feet.
Beneath the Upper Nine Feet, eastern block. Possible future Mineral
Potential.
TOTALS
Reserves:
Red Vein
Four Feet
0.25Mt
0.32Mt
Resources:
Upper Nine Feet
Four Feet
I5104C
(50% discounted for geological risk)
1.40Mt
(not quantified)
(60% discounted for geological risk)
(area east and south of layout)
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.16
ECKINGTON COLLIERY
4.16.1
BRIEF DESCRIPTION OF SITE
PAGE 251
Eckington Colliery is a small drift mine that is located close to Eckington village northeast of
Chesterfield and south east of Sheffield. The mine site is within a small industrial estate just
off the main A616 highway some 6km from Junction 30 of the M1 Motorway.
The underground workings are accessed via two short inclined surface drifts. The mine is
relatively new, the drivage of the Drifts having commenced in 1993. The mine exploits the
Flockton Seam (locally known as the Eckington Deep Soft) in a residual area between the
former National Coal Board Renishaw Park and West Thorpe Collieries. The Drift portals are
located to the east of and close to the River Rother and have been established on raised
ground, the level of which has been established above the level of the ‘100 year flood plain’ .
The main colliery site is located to the west of the River Rother and access to the Drift
Portals, which are sited some 110m away, is by raised gantry across the river. The main
mineral conveyor and the supply haulage both use the gantry. The main colliery site is
confined to an area of around 4,400m2 and has a screening plant, stock pad, out-loading
facility and weighbridge. In addition there are workshops, lamproom and materials stocking
areas. The main rope haulage for the intake drift is located on the west bank of the gantry.
An explosives store is located remotely in a field on the east side of the river.
The main management and administration offices are located on a separate site within the
adjacent industrial estate.
The mine, in common with other operators, found it difficult in 2002 to obtain insurance
without having to pay prohibitive premiums. The mine ceased operations for a short period
and was kept open on a ‘care and maintenance’ basis. The issue was eventually resolved,
those involved operating as a Partnership, negating the need for employees’ liability
insurance.
4.16.2
MINE BOUNDARIES, OTHER SURFACE CONSTRAINTS AND ISSUES
The mine licence area is triangular in shape and to some extent is controlled by Parish
Boundaries. The mine is bounded to the west by the seam outcrop, to the north by faulting
and old workings from West Thorpe Colliery (abandoned 1973) and the south by old
workings from Renishaw Park Colliery (abandoned 1957).
4.16.3
4.16.3.1
GEOLOGICAL ASSESSMENT OF THE MINE
Introduction
In this section, the geology of the mine and the reserves are discussed for Eckington. Note
that the mine is independent of the main producers: geological data and interpretations are not
readily available. This account is based largely upon selected data held in-house by IMC. Full
data access, and a more definitive account of the geology, is beyond the scope of this report.
The report text describes the geological setting of the mine and its reserves, and is supported
by Appendix tables, summarising the seam sequence, geological data and reserves (Tables 1,
2, and 3 respectively).
The drift mine dates from the 1990’ s, and lies in the exposed part of the eastern Pennine Basin
Coalfield, northeast of Chesterfield. The main seams outcropping across the mine area range
from the Flockton (locally known as the Eckington Deep Soft) up to the Second Waterloo.
The seams (Appendix Table 1) dip gently eastwards, beneath ground that rises east from the
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 252
valley of the River Rother. The Flockton Seam outcrops close to, and locally beneath the
River Rother and associated alluvial deposits (see later). The outcropping strata also include
prominent sandstones, including a thick sandstone that lies below the Lidget Seam.
The area surrounding the mine has been worked in various seams. A detailed appraisal of old
workings, and the locations of any old mine entries, is beyond the scope of this report: it is
assumed that such a study has been undertaken prior to granting the mining licence. The
larger local NCB collieries closed in the 1980’ s (Westthorpe to the north, and Renishaw Park
to the south). The northeastern boundary (see next) of Eckington Colliery lies parallel to a
significant fault zone (the Park Hall Fault, see next); two drifts cross this zone from
Westthorpe Flockton, to intersect the Parkgate and Thorncliffe seams within the area of
Eckington Colliery. These seams are part worked beneath the reserve block.
The mine boundary on the southern side is drawn conservatively north of a cautionary zone
against old workings in the Flockton Seam from the closed Renishaw Park Colliery. The
western boundary is in part a support limit (assumed for railway protection) and in part a
stand-off distance from the limit of the Rother alluvial deposits as depicted on the colliery
map. The northerly/northeasterly boundary is a proved fault, and (it is assumed) a stand-off
distance from Westthorpe old workings (including the Chavery Seam) and the Park Hall
Fault, which is roughly co-incident with a civil boundary. The northeastern and southerly
boundaries converge southeastwards.
The Rother alluvial deposits, and other surface features with mining cover significance, are
discussed later. No other superficial deposits are considered significant. The local succession
is typical of the Lower Coal Measures of this part of the coalfield. There are no igneous
features of any mining significance.
4.16.3.2
Structure
The mine lies in a generally un-faulted area southwest of the Park Hall Fault, one of the
coalfield’ s major NW-SE fault zones. This downthrows southwesterly, Westthorpe shaft lying
on the upthrown side, northeast of the mine boundary. The throw of the Park Hall Fault
hereabouts is not large, but the zone is nevertheless significant, and minor fault splays may be
expected in the more northerly parts of the unworked areas at Eckington, such as the fault that
forms part of the northerly boundary. The general easterly dip of the seam may swing, close
to such faults. Within the worked area to date, only minor faults have been intersected.
4.16.3.3
Reserves/Resource Assessment
Introduction
The mined seam is known locally as the (Eckington) Deep Soft. It is correctly known as the
Flockton; this term applies to the available geological data set at Renishaw Park and
Westthorpe collieries. The seam is a combination of the Roof Soft and Top Soft of the area
further southeast (e.g. Clipstone). The true Deep Soft Seam lies 5m to 10m below.
The Flockton is the only reserve seam. Other seams are discussed later. The operator’ s
assessment of tonnages is given in Appendix Table 3.
Roof Variations
The interval between the Flockton and Chavery seams is typically 15m or more, in the mine
area, and comprises mudstones and siltstones with local sandstones. A NW-SE oriented
sandstone roof belt, details unknown, is expected (from regional mapping) to overlie the
Flockton in the extreme southwest of the mine area. It is proved at Renishaw Station Shaft,
see Appendix Table 1. Another similar roof belt is present close to Westthorpe Shaft,
extending SE, but this is not expected to cross into the Eckington mine area.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 253
Seam Variations
Appendix Table 2 summarises readily available seam data from Renishaw Park and
Westthorpe collieries. The full seam is c. 1.60m to >2.00m thick in the Eckington area. An
upper coalbed (the Flockton Top Coal), c.0.25m thick, is thought to split from the Flockton
Main Leaf to the west, across existing Eckington present workings. The remaining Main Leaf
gradually thickens eastwards and – beyond the mine’ s eastern limit – significantly deteriorates
in terms both of ash and sulphur content.
Floor Variations
In the Renishaw Park and Westthorpe areas, the floor of the Flockton Seam is typically a
mudstone seatearth with stronger siltstones, and locally sandstones, close below.
Cover Variations and Ground Water
As noted in the Introduction, a full old workings investigation is beyond the scope of this
report, and it is assumed that this has been undertaken. It is noted however, that within the
area of the mine, no old shafts are recorded on the relevant Quarter Sheets of the British
Geological Survey (SK 47NW, 47NE); presumably because there are few coal outcrops of
any note in the area.
The mine entries lie within the Rother alluvial tract, as mapped on the published Quarter
Sheet SK47NW, with the surface outsets only 30m and 50m from the river itself. It is
assumed that the drifts were constructed after sufficient site investigations, with suitable
lining in the near-surface lengths. It is known, from investigations to the south (for Renishaw
Park Colliery in the 1970’ s) that the Rother alluvial deposits include gravels, thickness
uncertain, but possibly >8m in places.
A small lake, impounded by the Chapelwheel Dam, overlies part of the southwestern
extremity of the mine area. The lake is shown on the mining plan, with a SW-NE extent of c.
220m, and a width varying around 40m to 80m. The Flockton Seam is some 55m deep below
the central part of this feature. The strata between the seam and the surface are expected to be
largely claystones, although it is just possible that the interval between the Flockton and the
Chavery is largely sandstone (see Roof discussion, above). The present mining plan shows
that this area is excluded, together with an adjacent support area for a pylon. Any future plans
to work beneath the Chapelwheel Dam area should be preceded by a detailed assessment,
including consideration of any faults proved in the workings.
A fishpond, with adjacent marshy land, straddles the northeastern boundary of the mine at
approximately E445200/N379300. Its maximum mapped NNW-ESE length is c. 120m, and
its maximum W-E extent is c. 100m. The cover between the Flockton Seam and the surface is
expected to be >100m hereabouts. Note however that significant thicknesses of sandstone are
present in the strata between the seam and the surface. The area is shown as planned for
extraction in March 2004. A detailed study of the cover situation, particularly with respect to
any faults, is suggested.
Cover issues would also be a concern with respect to workings in a proposed reserves
extension to the southwest (Birley Farm area) see next.
Reserve Areas: Overview of Geological and Related Risk
Areas within the Mine Boundary
Appendix Table 3 summarises the reserve situation. Note that all these areas given below are
part under-worked in the Parkgate and Thorncliffe seams.
The various aspects of the described geology are now applied to the mining plan provided by
the mine operator, dated September 2002 (Plan A.O.R./2).
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 254
•
Areas to March 2003 and March 2004 (south of the main drivages). No significant
geological difficulties, relevant to reserves, are anticipated.
•
Areas to March 2003 and March 2004 (north of the main drivages). These may be prone
to NW-SE faults on the northeasterly boundary. Note also the fish pond described in the
section dealing with cover.
•
Area to March 2005, and March 2006. No significant geological difficulties, relevant to
reserves, are anticipated.
Potential Extensions beyond the Mine Boundary
IMC has also been provided with a plan illustrating potential extension of the Flockton
(“ Deep Soft” ) workings.
•
One area (around Birley Farm) lies south of the present mine boundary, in an area updip
from the abandoned Flockton workings from Renishaw Park. The River Rother, and
associated superficial deposits, crosses the southwestern margin of the block. The strata
between the Flockton Seam and the superficial deposits are likely to include significant
thicknesses of permeable sandstone. The southwestern limit is thought to be a fault, west
of which are further old workings. The fault details within the proposed block are
unknown. The area is considered at high risk from water ingresses.
•
A second area (“ Park Hall” ) lies northeast of the present mine boundary, generally
between the boundary and the mapped Flockton position of the Park Hall Fault and
associated fractures. The area is divided by a support pillar in the “ fish pond” area, (see
above). The more northwesterly part is considered to be at significant risk from faults, as
the NW-SE elongation makes it prone to faults on this orientation, as would be expected
to be associated with the Park Hall Fault. The larger part to the southeast is essentially unmined at depth in any seam (there are some Thorncliffe workings nearby) may also be
subject to faults, but at less risk than the northwesterly part, mainly because of the
increasingly available width of the panel, southwest of the Park Hall Fault. The basal part
of the seam progressively deteriorates to the east.
IMC considers that, of the proposed extensions to the mine, only the southeastern part of the
second area should be considered suitable for further investigation.
Assessment
An assessment of tonnages, based on the layout shown on the operator’ s 1:2,500 mine plan, is
given in Appendix Table 3. Note that most of these tonnages have been estimated by IMC for
the present exercise. The operator’ s tonnage assessments have been shown only on the plan
dealing with proposed extensions. IMC’ s tonnage estimates are based on a coal-in-section
average of 1.60m: it is understood that dirt from near the top of the seam (see Table 2) is
largely contained underground. The gross area tonnages have been discounted by 55% to
allow for pillars, with some addition for geological uncertainties, mainly faults (on the
northeastern side).
IMC’ s main comments (see Appendix Table 3 for details) are as follows.
•
The laid-out areas within the mine boundary are considered to constitute reserves.
•
These are generally considered to have a low geological risk, the main concern being
faults associated with the Park Hall Fault, to the northeast.
•
There could be mineral resources within the mine boundary, in the southwestern part of
the mine towards the Chapelwheel Dam (subject to detailed mine planning), and in the
outbye drivages areas (final pillar extractions prior to closure).
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
•
PAGE 255
The operators have identified two areas for possible mine extensions, as noted above. The
proposed extension in the southwest (Birley Farm area) is discounted, because of very
high risks related mainly to cover issues. The northwestern part of the eastern proposal
(“ Park Hall” areas) is also discounted, mainly for fault risk. The main part of this eastern
proposal is considered more secure, and is classed here as Resources, prior to detailed
evaluations, licensing, etc.
The following table summarises Table 3 shown in the Appendix to this mine along with the
plans at the end of this section of the report.
Table 4-78
IMC Re-assessment of Eckington Reserve/Resource: Summary (01/12/02)
Million Tonnes
Seam
Reserve
Resource
Total
Mineral Potential
Flockton (“Deep Soft”)
0.28
0.29
0.57
-
Total
0.28
0.29
0.57
-
4.16.3.4
Other Seams of Interest
All other seams of mineable depth are thin and are therefore of no interest.
4.16.3.5
Exploration
No exploration is expected. The seam is sufficiently known in the mine licence area, and only
minor faults are expected, other than along the northeastern border. However, it is worth
noting here that any developments into areas overlain by bodies of water at the surface, or
within the Rother alluvial belt (see sections on Cover and possible extensions to the mine)
should be investigated, at least by desk studies, prior to commitment.
4.16.4
4.16.4.1
MINE CHARACTERISTICS AND CONSTRAINTS
Infrastructure
The underground workings are accessed via two arched 1 in 3 inclined surface drifts some
60m in length. The mine is relatively new, the drivage of the Drifts having commenced in
1993. The drift portals are on raised ground within the flood plain of the River Rother.
The main infrastructure consists of two roadways driven in line with the surface drifts in an
east-south-easterly direction some 1,200m within the Flockton seam at a gradient of around 1
in 12 dipping. The main roadways were first driven in seam, additional width being extracted
to form room for the stowage of dirt as floor strata was then extracted to provide additional
height and the room to set small section arches. The mine does not have dirt tipping facilities
and it is essential that any dirt extracted is stowed underground. The main roadways are
currently being extended to a point some 1,300m from the drift portals.
4.16.4.2
Layouts
Production is by simple pillar and stall working. The stalls are bored and fired and filled out
utilising a single electric Bobcat LHD machine. The stalls are normally 1.5m high by 5.6m
wide, supported by box-section girders on timber posts. Supporting materials are salvaged
and re-used whenever possible. The stalls are normally worked double shift, days and
afternoons, five days/w. Maintenance and move-ups are done on Saturday. Six stalls are
active at any one time ensuring continuity of production.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 256
The use of explosives in the working method has during 2002 been a problem due to the
difficulty of supply of suitable explosives and the necessary exemptions for their use.
The pillars left are nominally 10m x 10m. The stalls have in the past been driven in a northnorth-east direction but recent working has been in a north-north-west direction as extensively
used at the adjacent Renishaw Park Colliery. This has been found to enhance working
conditions.
4.16.4.3
Roadways and Face Conditions
In general mining conditions are good. The seam has a strong roof and within the working
stalls simple props and bars are used for support that can be withdraw and re-used. However,
the seam is liable to floor lift which is now affecting the main roadways. Conditions
deteriorated in 2000 due to an increase in the ingress of water into the mine during a period of
heavy and sustained rainfall. A programme of repairs is currently being undertaken within the
Main Intake mainly in the form of dinting. A Hausher Dinting machine has been installed to
complete the works.
The Main Return also requires repair. The main fabric of the roadway is in reasonable
condition, however, the sides of the road were not lagged between the arches allowing the
strata to ingress into the roadway. It is therefore planned to dint the roadway and shutter the
loose mineral into the sides. From experience it is anticipated that once the immediate soft
floor has been removed through dinting, future floor lift should be minimal.
Water enters the mine at the northern end of N1’ s, an abandoned working area, and 20m to
50m outbye from N1’ s along the main drifts. Small emissions also take place from a layer of
coarse sandstone that underlies the seam. Water ingress increases 3 to 4 days after any period
of prolonged rain or flooding of the River Rother. In normal circumstances the total quantity
of water is 70gpm or less, rising to 140gpm in adverse circumstances (possibly for 10 – 12
weeks per year). The working stalls are generally kept dry. Water is collected in lodgements
and pumped to surface via three stage pumping. It is estimated that currently some 150 –
200gpm is pumped for around 8 hours each day. The water is allowed to settle in a series of
tanks prior to discharge into the River Rother.
4.16.4.4
Coal Clearance
The main coal clearance is by 36” belt conveyor mounted on 42” structure. Significant
improvements have recently been made to the system including the installation of new belting
throughout. A single FSW drive runs through the main intake. A Lioness Drive is used at the
inbye end delivering onto the main conveyor from the working area. The conveyors run at
around 70t/h. Due to the confines of the surface infrastructure output is restricted to about
200t/d.
4.16.4.5
Manriding and Materials Transport
Materials transport is by rope haulage. There are no manriding facilities.
4.16.4.6
Other services
The mine has electrical and compressed air supply. Methane drainage is not required.
4.16.4.7
Manpower and Safety
Twenty-five men are currently employed at the mine.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.16.4.8
PAGE 257
Ventilation
The main ventilation fan provides sufficient ventilation to satisfy requirements and is
supplemented by auxiliary fan systems.
4.16.4.9
Subsidence
All the working areas shown within the mine boundary in the Flockton Seam are within the
five-year development plan. The potential extension areas are outside the current mine
boundary. The workings will be mainly under agricultural land but will pose no drainage
problems. The Trans Pennine Trail will be marginally affected in 2003/4.
The cost of mining subsidence damage is estimated to be minimal at less than 10 pence/t.
4.16.4.10
Coal Preparation Facilities
The mine has a dry screening plant to size the saleable product, out-loading stocking pad and
lorry weighbridge.
4.16.5
4.16.5.1
HISTORIC PERFORMANCE
Production
Table 4-79
Historical Production Performance at Eckington
Eckington
1999
2000
2001
2002
(estimated)
Actual Output
million tonnes – saleable
0.031
0.032
0.027
N/A
Budgeted Output
million tonnes - saleable
0.030
0.036
0.032
0.036
Difference
million tonnes - saleable
+0.001
-0.004
-0.005
Since the mine’ s inception in 1993, annual production has steadily increased to over 30,000
tonnes (in 1999). The mine continued its upward trend in the early part of 2000 but the latter
part of the year was adversely affected by a combination of poor roof conditions in the
northern working area and floor lift in the main access roadways. Much of the deterioration
had been due to a temporary increase in water ingress due to the inclement weather
experienced throughout autumn 2000. Several weeks’ production was also lost in November
2000 as the mine was closed as a precaution due to it being at risk of flooding from the
adjacent River Rother, which over-flowed. Production in 2001 was also affected by minor
faulting. The mine has subsequently undertaken a roadway repair programme.
Production in 2002 has been affected by the difficulty in obtaining insurance renewal and
several weeks production was lost whilst the situation was resolved.
4.16.6
FUTURE MINING PROJECTION
The Strategy is to continue the development of the Flockton seam to the east and south, albeit
that the southern area has been curtailed prematurely due to geological deterioration and a
small ingress of water from the roof strata. The plan is to develop and maintain two working
areas to provide ready access to alternative working zones, thus giving continuity of
production. Included within the plans is the continuation of extensive repairs to the main
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 258
roadways. This work is necessary to ensure adequate clearances for access to the working
areas.
An intrinsic part of the mine strategy is the acquisition of a second Bobcat LHD machine and
increase in underground manpower from 25 to 30. This will enable output to be lifted to
above 40,000t/a from 2003 onwards. It was originally envisaged that this acquisition would
take place in April 2002. However, due to the protracted repair works to the infrastructure
and interruption to development caused by faults, this expansion has been delayed.
4.16.7
4.16.7.1
PRODUCTION AND DEVELOPMENT FORECASTS
Production
Until the acquisition of a second LHD machine is made and a second working area fully
established, output will continue with the current method of pillar and stall working utilising a
single Bobcat LHD machine for filling out. The stalls are normally 1.5m high by 5.6m wide,
supported by box-section girders on timber posts. Supporting materials are salvaged and reused whenever possible. The stalls are normally worked double shift, days and afternoons,
five days/w. A full team is deployed during day shift and a loading-out team during noon
shift. Maintenance and move-ups are done on Saturday. Six stalls are active at any one time
ensuring continuity of production.
From proving by the past Thorncliffe and Parkgate seam workings the proposed area should
generally be free of geological disturbance, although minor faulting and variable seam and
roof conditions cannot be discounted. Pillar edges left by the workings below will have to be
negotiated but have been traversed successfully before, problems being confined to the north
area only. Diversifying into more than one area will give security against further problems.
With the introduction of the second LHD machine and with a requisite increase in manpower
it is intended to lift annual output to over 40,000 tonnes from 2003 onwards. The introduction
of the second machine will give increased production capacity and limit losses due to
breakdowns (no production is able to take place currently when the LHD is broken down)
albeit a significant number of spare parts are held at the mine.
The acquisition of a second LHD machine is a key element to ensure the future viability of the
mine. In the first instance it will give valuable cover to the current machine, which has been
in use for a significant time, and at some stage will itself, have to be replaced. This will give
security of production at around 36,000t/a and the option for increasing to above 40,000t/a
from 2003 onwards as planned.
The main spine roadways are in the process of being extended to the east by some 350m. Due
to cash flow constraints work on the development had been delayed. However, upon receipt
of operating aid, work commenced and is now well advanced, although slightly behind
schedule due to minor faulting. The main roadways are arched and coal is removed from their
flanks to provide stowage room for the dirt excavated from the floor (dirt-absorbing
headings).
To ensure that two working areas are maintained, and in light of the difficulties in extending
the workings further to the south, the mine has also been developing a production area to the
north side of the main developments.
Assuming that conditions remain favourable and floor lift remains under control, the
development programme should provide timely access to the working areas planned during
the Five Year period.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 259
It is also important to note that the mine is investigating the possibility of eliminating the use
of explosives by the introduction of mechanised coal cutting. Various heading machines are
being assessed for their suitability for working within the confines of the seam height.
4.16.7.2
Risk
Production at Eckington Colliery is by simple pillar and stall working, which is a flexible
method of work capable of overcoming minor faulting and seam anomalies.
The tectonic structure at Eckington is well understood and is unlikely to pose any severe
constraint on production.
At times of heavy rainfall the mine could sustain losses of output following flooding of the
River Rother, and loss of access to the explosives store. In addition, heavy rainfall does
eventually result in nuisance water in the underground workings.
Output losses have also been associated with the problems of sourcing suitable explosives in
the past. These difficulties are likely to increase into the future as supplies withdraw from this
shrinking market and mine owners become increasingly dependent for supplies from abroad.
4.16.7.3
Long Term Plans
Sufficient reserves are available within the current take to sustain production at planned levels
for up to seven years. There is also a possibility that the main infrastructure roadways could
be further extended west assuming that the necessary planning permission and licences can be
obtained. Resources estimated at 0.29Mt would extend the life of the mine for a further seven
years.
4.16.8
OPPORTUNITIES FOR FURTHER INVESTMENT
The colliery works a simple pillar and stall system planned to produce around 40,000t/a. The
mine therefore has only minimal capital requirements. An essential part of the mine strategy
is the introduction of a second load haul dump vehicle to improve the production cycle. A
scheme for the procurement/development of a suitable machine would probably be regarded
as Category 2 investment.
The possibility of eliminating the use of explosives by the introduction of mechanised coal
cutting is also being pursued. As the mine infrastructure progresses to the east it will also be
necessary to extend the electrical system. The development of the main access roadways
could also be regarded as a capital scheme. These schemes would also possibly attract
investment aid.
The mine has however expressed concern over the difficulty that it will have in securing the
additional 70% of costs.
As outline above, the mine also has the possibility of extending its infrastructure outside its
current licence boundary. This could also be considered as a potential for future investment
aid.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 260
380000
s
sit
po
e
D
ial
ll uv
A
Eckington
Colliery
st
We
h
t
r
No
Pa
rk H
all
Fau
lt (a
ppr
oxi
ma
Min
te s
urfa
eB
ce
oun
pos
dar
itio
y
n)
d
e
g
og
l
r
te
Wa
t
c
tri
Dis
Eckington Colliery
FLOCKTON SEAM
RESERVES PLAN
September 2002
Westthorpe
Colliery
ifts
Dr
e
f
clif
rne
o
Th
Cautionary Zone against
no
t
Westthorpe Workings
k
c
Flo
Support
Area
379500
Railway
Eckington Flockton Seam
Potential
Mar
Extension
2003
Area Worked by Partial Extraction
NE
Area
r
the
Ro
er
Riv
Mar
2003
Chapel Wheel
Dam
South West Area
Support
Area
Birley
Farm
Pillar
379000
Mar
2004
Mar
2006
Driv
age
s Ar
ea
South East Area
Eckington Flockton Seam
Potential Extension
"Park Hall"
Mar
2005
Mine Bou
ndary
Approximat
e Edge of
Mar
2004
Renishaw
Park Worki
ngs
Figure 4-33
I5104C
444500
445000
444500
444000
Eckington Flockton
Seam
Potential Extension
"Birley Farm"
Eckington Colliery: Flockton Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 261
ECKINGTON COLLIERY: APPENDIX
TABLES 1 TO 3
ECKINGTON TABLE 1: SEAM SEQUENCE
(based on Renishaw Station Shaft c. E 444500 N. 378100)
MAIN SEAMS: reserve seam
in BOLD
SEAM THICKNESS, approx.
(metres)
INTERVAL, approx
(metres)
Lower seams outcrop progessively to the west
Thin coals above the Second Waterloo (Swallow Wood)
Second Waterloo (part)
1.35
Lidget (First Ell) (part)
0.25
45
48
Chavery
0.75
Flockton
2.00
15
(Eckington Deep Soft)
5
Deep Soft (Sitwell Thin)
0.60
28
Deep Hard (part)
0.70
17
Parkgate (upper bed)
0.35
Typically >2
Parkgate (lower bed)
0.60
15
Thorncliffe (Tupton, part)
0.50
70
Silkstone
2.30
(Yard &Blackshale, part)
4
Silkstone (Blackshale, part)
c. 2.50
Thin coals below Silkstone.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 262
ECKINGTON TABLE 2: FLOCKTON SEAM: DATA FROM NEIGHBOURING COLLIERIES
LOCATION
Eastings
Seam section/splitting (cm)
Seam-lessSeam-less-dirt
Northings
dirt Ash%
Sulphur %
Renishaw Park Dip
Lake No. 2
Borehole (u/g)
E. 444850
N. 378520
Westthorpe
Colliery Shaft
E. 445353
N. 379630
Westthorpe Surface
Drift
Westthorpe Sample
ND/137/68
Base (Flockton) at:
E. 445292
N. 379920
E. 445290
N. 379660
Approx.
445535
379619
Westthorpe Sample
A.1/7.10.48
E. 446060
N. 380330
Section just NW of
Westthorpe Shaft
Coal 25 (Flockton Top Coal)
Dirt 10
Coal 152 (Flockton Main Leaf)
Coal 15, 0.25m below.
Coal 25 (Flockton Top Coal)
Dirt 10
Coal 130 (Flockton Main Leaf)
Coal & dirt 1.65
-
-
-
-
-
-
Coal 25 (Flockton Top Coal)
Dirt 10
Coal 131 (Flockton Main Leaf: part inferior)
Coal 22 (Flockton Top Coal)
Dirt
9
Coal 129 (incl. 3 cm dirt) (Flockton Main Leaf)
Coal 21 (Flockton Top Coal)
Dirt 10
Coal 127 (Flockton Main Leaf)
-
-
-
-
9.2
2.2
ECKINGTON TABLE 3: FLOCKTON SEAM, RESERVES SUMMARY
RESERVES,
Mt
(estimated)
0.06*
RESOURCES,
Mt
(estimated)
-
MINERAL
POTENTIAL,
Mt (estimated)
-
0.12*
-
-
0.05*
-
-
0.05*
-
-
Other potential working
areas within mine
boundary
-
-
Not quantified
Proposed extension,
southwest area around
Birley Farm.
Proposed extension
(“ Park Hall area” ): eastern
area between mine
boundary and the Park Hall
Fault.
-
-
-
-
0.29*
-
AREA
“NE” area, eastern end
north of the main drivages.
“SE” area, eastern end
south of the main drivages.
“SW” area, adjacent to the
pylon pillar.
Drivages area: assumed
extraction after inbye
workings are finished.
TOTALS
I5104C
0.28
0.29
-
IMC COMMENTS
*IMC’ s assessment, based on 1.6m coal in
worked section, the gross area being
discounted by 55% (mainly for pillars).
*IMC’ s assessment, based on 1.6m coal in
worked section, the gross area being
discounted by 55% (mainly for pillars). The
tonnages are nominal, to allow for late-stage
pillar extraction, and are assessed only inbye
from the end of the initial drivage runs.
The area in the southwest of the mine, towards
the Chapelwheel Dam, is not laid out, and
some Mineral Potential is assumed here,
subject to detailed mine planning.
Discounted: high risk of surface-related, and
water problems.
*IMC’ s assessment for the eastern part only.
This part (southeast from Westthorpe Colliery)
could rate as Resources. Tonnage based upon
1.6m coal in the worked section, the gross area
being discounted by 55% (mainly for pillars.
(The operator assesses 0.28Mt for the full
eastern extension area, but the area northwest
from Westthorpe is considered very high risk
from faults, and is discounted here.)
Note that the IMC assessment includes some
tonnages from the Drivages area., to represent
local pillar extraction prior to mine closure.
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.17
HAYROYDS COLLIERY
4.17.1
BRIEF DESCRIPTION OF SITE
PAGE 263
Hayroyds Colliery is a long established drift mine situated on the outcrop of the Whinmoor
seam. The mine site is located on a hillside above the village of Clayton West in Yorkshire,
between Huddersfield and Barnsley. The mine is accessed via steep and narrow country
lanes, however, the main A636 runs close by and junction 38 of the M1 Motorway is only
some 7km distant. It has an extensive surface infrastructure including a coal preparation plant,
workshops, offices and spoil tipping.
4.17.2
MINE BOUNDARIES, OTHER SURFACE CONSTRAINTS AND ISSUES
The working area is bounded to the north by previous workings and to the south, east and
west by major faulting. The geological structure is well known having been proven in other
seams by several adjacent mines. The mine works under mainly agricultural land. The area
has been previously worked in the Wheatley Lime (90m above) and Old Hards (170m above).
Drifts have been driven into the Whinmoor seam and the necessary precautions against
inrushes taken.
4.17.3
4.17.3.1
GEOLOGICAL ASSESSMENT OF THE MINE
Introduction
In this section the geology of the mine and reserve zones are discussed for Hayroyds. Note
that the mine is independent of main producers: geological data and interpretations are not
readily available. The following is based largely upon selected data held by the British
Geological Survey. Full data access, and therefore a more definitive account of the geology, is
beyond the scope of this report.
The report text describes the geological setting of the mine and its reserves, and is supported
by Appendix tables, summarising the seam sequence, geological data and reserves (Tables 1,
2, and 3, respectively).
The mine is in the exposed part of the eastern Pennine Basin Coalfield, west of Barnsley. The
main seams outcropping across the licence area range from the Blocking up to the Flockton
group (see Appendix Table 1, based upon the NCB Hoyland Bank Borehole,
E427424/N410550). The seams dip gently southeasterly. The mined Whinmoor Seam
outcrops north and west of the colliery. The deepest unworked Whinmoor areas – to the
southeast – would be at depths >150m below surface.
The outcropping strata include two thick sandstones (above the Flockton group, quarried in
the past near High Hoyland village; and the Lepton Edge Rock, above the Green Lane Seam).
It must be assumed that these sandstones are significantly fractured, and likely to be waterbearing, particularly in undermined areas and in faulted zones. Various mine entries are
present along the outcropping coals (and, locally, ironstones). Some of these are specified on
the published Geological Survey Sheet Yorkshire (West Riding) CCLXI. S.E.). It is beyond
the scope of this report to undertake a full old workings assessment, and it is assumed that this
has been made on behalf of the mine owners.
No significant superficial deposits (other than landslip material, see below) are expected. The
local succession is typical of the Lower Coal Measures of this part of Yorkshire. There are no
igneous features of any mining significance.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.17.3.2
PAGE 264
Structure and Landslips
The main part of the mine, including most worked areas, lies in a generally un-faulted area
between two NW-SE fault zones. These zones are the northwesterly extensions of the
Mapplewell and Cawthorne-Barebones faults, north and south, respectively, of Barnsley (see
the British Geological Survey’ s Barnsley Memoir: Mitchell et al. 1947). The latter fault zone
has been proved as an array of minor faults in the Whinmoor Seam, in the southwest of the
licence area. Between these fault zones, the bedding dip is typically to the southeast. The
High Hoyland Fault trends SW-NE across the southeastern parts of the licence area. All these
faults are probably normal in style, although the main NW-SE named faults may well have
some strike slip attributes.
The Geological Survey County Sheet shows an area of landslip extending 0.7km (SW – NE)
by up to 0.4km (NW-SE) in the southeast of the licence area, just southwest of High Hoyland
village. The details of this landslip have not been investigated, but a full assessment of
possible surface movements would be required should mining proceed into this area.
4.17.3.3
Reserves/Resource Assessment
Introduction
The reserve situation is summarised in Appendix Table 3. Only the Whinmoor Seam has been
included. The seam has been extensively worked near its outcrop. It has been proved downdip
in a number of comparatively recent (1960’ s to 1980’ s) boreholes by the NCB, mainly north
of Hayroyds, for the former Emley Moor and Parkmill collieries. North of Hayroyds, the
seam gradually unites with the overlying Beeston Seam. However, the seams are >10m apart
in the Hayroyds area. Summary data for the Whinmoor coal group, drawn from selected
recent boreholes to the north, are provided in Appendix Table 2.
Roof Variations
The Barnsley Memoir (pages 30 – 31) describes the Whinmoor Seam as typically overlain by
a substantial sandstone. As noted above, the Whinmoor and overlying Beeston Seam unite
north of Hayroyds, and the sandstone, often >10m thick, occupies this interval. It may form
the immediate or close working roof in parts of the mine. At Langley Borehole
[E425164/N411575] to the northwest, the Whinmoor is partly washed out (eroded by the
sandstone-depositing river), and some minor washouts might be expected in the workings.
Seam Variations
The Whinmoor itself is typically in two main coalbeds north of Hayroyds (three coalbeds
according to the Barnsley Memoir), the Top and Low Whinmoor coalbeds splitting
northwesterly across the Hayroyds area. At Hoyland Lane Borehole, these are only 0.16m
apart, the full seam being 1.23m thick. In present working districts (approximately
E426400/N409700) the seam section is understood to average 1.49m at:
Coal 0.20, Dirt 0.10, Coal 0.38, Dirt 0.38, Coal (including inferior coal) 0.43
The thick lower dirt is assumed to be the Top/Low Whinmoor split. A regional appraisal of
the borehole data north of Hayroyds, undertaken for this exercise, shows the split striking
SW-NE, opening to the northwest. It is assumed that the seam thins to the southeast, as this
split decreases, and a seam thinning is known from the Hayroyds workings.
The Top Whinmoor is usually the thicker bed, and Appendix Table 2 shows that, to the north
of the reserves, it typically has a seam-less-dirt ash between 10% and 13%, with seam-lessdirt sulphur c. 2.5% to 5.0%. Rank, based upon the NCB’ s Coal Rank Code, varies between
400 and 500 (high volatile strongly, to very strongly caking bituminous coals). The Low
Whinmoor is typically inferior (ash 15% to >20%; sulphur >5.0%). It is expected that the
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 265
quality of the full Whinmoor improves as the two coalbeds unite: that is, the seam where
worked should be of better quality than the quoted data.
Floor Variations
The floor is thought to be typically a mudstone seatearth.
Cover Variations and Ground Water
The two significant sandstones in the near-surface, in the southeastern parts of the reserves
area, could contain and transmit water (see introductory section). Intermediate sandstones
include those in the interval between the Whinmoor and Beeston. A full mine water
assessment is beyond the scope of this report, particularly as any workings in other seams
have not been investigated. However, the following generalisations may be made.
•
Cover between the Whinmoor and the surface will increase generally to the southeast,
possibly achieving >150m towards the southeastern margins of the reserves area.
•
The near-surface sandstones lie above these deeper parts of the reserves area, and should
be >110m above the Whinmoor thereabouts.
•
Careful assessment of the mine water situation should be made, where workings approach
larger faults that downthrow these sandstones nearer the working seam. This comment
applies mainly to the High Hoyland Fault.
•
As a generality, the pillar-and-stall method of working should minimise ingress of water
from sandstones and fault zones.
In conclusion, it is considered that there should not be a significant limitation to working
areas with respect to natural ground waters, apart from the area adjacent to the High Hoyland
Fault, see below. However, a study, integrated with a full appraisal of the old workings
situation, is recommended.
Reserve Areas: Overview of Geological and Related Risk
The various aspects of the described geology may now be applied to the mining plan, dated
July 2002 (Reference HR/42B). Key issues are as follows.
•
All areas southeast of a line drawn SW-NE between [E426500/N409500] and
[E427000/N410000] are likely to thin progressively to <1.45m, possibly to <1.30m (as at
Hoyland Bank Borehole, see Appendix 2) and therefore will progressively become
unworkable using the present mining method. It is understood that the operator is
addressing the thinning, by considering the use of augers: this is unproved at Hayroyds.
The degree of thinning of the seam is not known at the present time and will be
determined by working.
•
The thinning area is considered to constitute Resources, for the purpose of this exercise.
This is taken as the six southerly blocks of the area shown on the plan.
•
Area planned to March 2003. No significant geological concerns are expected, although it
is noted that an old shaft (possibly to seams of the Flockton group) is located directly
above the planned workings at approximately E426800/N409930 (see Geological Survey
County Sheet).
•
Area planned to August 2003: no significant geological problems are expected.
•
Area planned to March 2004. The inbye (southeasterly) extremities of this area will
approach the Cawthorne and High Hoyland fault zones, with the possibility of first
meeting the former of these, in the Whinmoor. It may be possible to work through some
of the minor faults associated with the Cawthorne Fault. Note, with respect to the High
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 266
Hoyland Fault, the comments in the section above, dealing with cover. The block is also
proximal to the area of landslip noted earlier, and an assessment is recommended,
regarding the possibility of cumulative extractions (including any workings in other
seams) stepping the fault in the landslip area. This block may also be affected by thinning
but for the purposes of this report is included in the reserves
•
Area planned from March 2004 to September 2005. This area is likely to intersect the
Whinmoor position of both the Cawthorne and High Hoyland faults, and (on the east) to
undermine the mapped landslips. See also above, regarding cover/near surface sandstones.
This area is considered to be at significantly greater risk than others. Seam thinning is
also expected to be prevalent in these blocks
•
Area planned to December 2005. This area includes an old shaft, presumably to the
Parkgate Seam (see Geological Survey County Sheet). This block may be affected by
seam thinning but has been included in the reserves.
•
Area planned to April 2006. This area lies beneath the mapped landslips and is likely to
contain a thin seam section.
•
Area planned to May 2007. On the eastern side, this lies close to the mapped landslips.
Note that the County Sheet records an old shaft at approximately E426650/N409730, to
the Parkgate Seam.
•
Area planned to December 2007. This NNW-trending extension would extend beyond the
present licence boundary. It would approach within c. 80m of the old New Inn Colliery
(Bank End), one shaft of which is recorded (on the County Sheet) as extending below the
Green Lane Seam. The mapped outcropping seam in this area is the Parkgate.
Assessment
A tonnage assessment based on laid-out areas shown on the 1:2,500 mine plan, is given in
Appendix Table 3. Note that these tonnages have been estimated by IMC for the present
exercise, and are based on a coal-in-section average of 1m (it is understood that the dirt is
largely contained underground). A discount of 50% has been applied to the gross areas, to
account for pillars, and any geological difficulties, mainly faults. However in the areas
expected to contain a thinner section a discount of 70% has been taken until these areas are
proved at which point the areas can be re-assessed.
IMC’ s main comments (see Appendix Table 3 for some details) are as follows.
•
As discussed earlier, it is considered that thinning to below c. 1.45m may be inappropriate
to the present mining system, and therefore the laid-out areas south and east from present
and recent working areas are at significantly greater risk. The exact cut-off, both in seam
thickness, and in the map positions of successive isopachs, are uncertain.
•
The laid-out panel, extending northwest through the licence boundary, is taken as one
reserves area for convenience. An area immediately west of this block has also been
assessed as reserves as it is expected to be very similar to the areas at present being
worked. It is possible that further areas north of this boundary could be included, as
mineral potential, but this would require further investigation.
•
The inclusion of reserves and resources in this report does not take account of any old
workings issues, particularly with respect to the abandoned shafts discussed earlier.
Again, it must be assumed that these concerns will have been addressed prior to granting
of the mining licence.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.17.3.4
PAGE 267
Other Seams of Interest
The seams below the Whinmoor are probably thin. Seams above are likely to have been
worked in places, or too close to old workings/the surface, for further mining. It is therefore
concluded that there are no other seams of interest.
4.17.3.5
Exploration
No specific exploration is anticipated. However, there are some aspects of the mine’ s
geological and mining setting that are appropriate to more detailed desk studies, particularly
the varied relevance of old workings (it is assumed that this has been done) and any potential
for mobilising landslip ground. It is possible that drilling of specific old shafts may be
required, to ascertain their depths. However, IMC has assumed that relevant shafts recorded
in the proposed mining area have been cleared through licence.
4.17.3.6
Geological And Reserve/Resource Conclusions
The following conclusions are drawn.
•
The main geological constraints are seam thinning and quality, particularly sulphur
content; the latter could marginalise output from Hayroyds. Seam thinning is the key
constraint, as the present mining method depends upon a minimum thickness of c. 1.45m.
On regional grounds, the seam is expected to thin below this over some of the remaining
laid-out areas, south and east of the present working districts.
•
The possible use of auger mining in these thinner areas is un-proved, suggesting that these
areas should be classed as Resources.
•
Apart from seam thinning, the main geological uncertainties are expected to be faults
(areas planned to be worked between May 2004 and April 2006), locally with the added
issue of surface instability in the landslip area. Some discounting of the idealised pillar
and stall layout is indicated for these areas, especially the areas planned between
September 2004 and September 2006.
•
There are various issues relating to old workings, including shafts. Although not detailed
in this exercise, it is emphasised that a full appraisal of these should be available.
Uncertainties regarding old shafts and workings could lead to abandonment of some of the
identified reserves.
The following table summarises Table 3 shown in the appendices to this mine along with the
plans at the end of this section of the report.
Table 4-80
IMC Re-assessment of Hayroyds Reserve/Resource: Summary (01/12/02)
Million Tonnes
Seam
Reserve
Resource
Total
Mineral Potential
Whinmoor
0.18
0.05
0.23
-
Total
0.18
0.05
0.23
-
4.17.4
4.17.4.1
MINE CHARACTERISTICS AND CONSTRAINTS
Infrastructure
The main drift, which is sited at the main colliery surface, is used as the return airway and for
coal clearance (by conveyor) and supplies. An adit, situated remotely, some 950m to the NE
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 268
of the main colliery surface, provides the main intake airway. Three other Adits (two of
which are disused) are located at the main colliery site.
The main roadways are formed as part of the main production system of pillar and stall work.
The main access roadways are now advanced some 1,700m to the east of the mine entries.
Additional height is made by the extraction of floor dirt, which is stowed underground.
Old stalls adjacent to the main roadways sealed by the placing of the washery discard. The
discard gravitates down the main drift and is then pumped into the old workings.
4.17.4.2
Layouts
Production is concentrated in the Whinmoor Seam in an area to the east of the mine entries at
a depth of around 145m. The seam generally dips to the southeast at a gradient of around 1 in
7.
The mine works a simple pillar and stall system, undercutting using an AB15, boring and
firing and loading out with a ‘Bobcat’ type load haul dump machines (LHD) to a central
loading point and then out to the surface via conveyor. The LHD machines, which are
electric and fitted with cable reelers have been developed and manufactured specifically for
the mine by J Flack & Sons Ltd.
The stalls are normally driven in-seam 5.79m wide leaving 14m square pillars, although pillar
size varies with depth. Normally five stalls are advanced simultaneously, the cutting machine
flitting between headings. Removal of mineral is undertaken utilising the LHD machines that
carry the material to a common loading point at the end of the conveyor system. The
conveying system is extended periodically enabling the loading point to be moved forward,
optimising the distance of vehicle travel. Currently two machines with 0.75 tonne capacity
and a prototype machine with 2 tonne capacity are being used.
4.17.4.3
Roadways and face conditions
The main roadways and working stalls are generally in good condition. The seam has a
strong and regular roof and there is little problem with floor lift. The workings are all in-seam
and the extraction of floor dirt is minimised. The height in the main roadways is therefore
quite low, but is designed to accommodate the supply systems.
4.17.4.4
Coal Clearance
Coal clearance is by a 36” belt conveyor system that runs in the main return, delivering via
the main return drift access to the Coal Preparation Plant.
4.17.4.5
Manriding and materials transport
Materials supply is by rope haulage, which shares the Main Return Drift with the conveyor
system. Manriding has recently commenced with the introduction of outbye manriding along
a section of the conveyor system. It is intended to up-rate the entire main trunk belt for
outbye manriding. The possibility of developing a FSV manrider is also being considered.
4.17.4.6
Other services
The Colliery has to deal with water ingress from adjacent old mine workings. The water
make of around 25m3/h, which is high in iron content, is utilised in the coal washing plant,
where much of the iron drops out. The mine water then passes through settling ponds before
being discharged into the local watercourse. It must be noted however, that the working area
is kept generally dry.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.17.4.7
PAGE 269
Manpower and Safety
The mine works two extended shifts and is operational from 05:30 to 20:00 hours, which
requires a compliment of 24 men. At present there are 21 men on books and 3 ‘green labour’
are to be taken on for training.
4.17.4.8
Ventilation
The colliery has low makes of gas and is classified as a non safety lamp mine other than at the
face. It is also of low risk to spontaneous combustion.
4.17.4.9
Subsidence
There are few buildings in this largely agricultural land. Mining is shown planned to work
beneath a hill. A landslip has occurred on the southern flank of this hill and it will be
undermined if mining proceeds as planned. A number of structures have been built over this
landslip. A full study of the present stability of the landslip should be undertaken prior to
mining. If the risk of landslip is found to be unacceptably high then a majority of the planned
panels would be at risk.
Subsidence is currently being monitored and no surface movement has been recorded to-date,
the pillars within the mining system being self-supporting.
In the absence of landslip problems, subsidence damage costs should be low and in the order
of 10 pence/t.
4.17.4.10
Coal Preparation Facilities
All the run of mine product is washed and the dirt segregated primarily through a cyclone.
Whenever possible the discard is pumped back down the mine to seal off old stalls.
4.17.5
HISTORIC PERFORMANCE
4.17.5.1
Production
Table 4-81
Historical Production Performance at Hayroyds
Hayroyds
1999
2000
2001
2002
(9 months)
Actual Output
million tonnes – saleable
0.041
0.034
0.031
0.022
Budgeted Output
million tonnes - saleable
0.043
0.038
0.040
0.031
Difference
million tonnes - saleable
-0.002
-0.004
-0.009
-0.009
In 2000 output was adversely affected by difficulties in accessing and opening out a new
replacement production area to the South. Further problems occurred through the latter part
of 2001, a series of faults badly affecting the new area. This has necessitated switching
production to the east, the establishment of which has further limited output in 2002.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.17.6
PAGE 270
FUTURE MINING PROJECTION
Albeit that in recent years, due to unexpected faulting and seam thinning, production areas
have had to be altered, the strategy has not fundamentally changed. That is that the mine is to
continue extending the working area to the south and east, consolidating production at around
42,000t/a in-line with that achieved in 1999/2000.
The mine has developed a relatively efficient semi-mechanised pillar and stall system, with
custom built LHD electric cable reel machines designed to work within the low working
section. It is expected that the seam section will continue to thin as the workings progress
south and east. An essential part of the mine plan therefore is the development of mining
equipment suitable for thin seam working. The strategy includes for the development of
LHD’ s with lower working height coupled with larger load carrying capacity to improve
productivity. The development of an auger machine for coal extraction is also planned for the
future. If successful this would enable selective mining to be undertaken, leaving the dirt
bands underground, reducing transport and washing costs. It is also intended to develop new
cutting / heading machines to minimise the use of explosives.
4.17.7
4.17.7.1
PRODUCTION AND DEVELOPMENT FORECASTS
Production
In recent years the mine has experienced difficulties and has received operating aid. In 2001
production was severely affected by a series of faults. These faults were unexpected, the area
having been previously worked in other seams without geological disturbance. The
disposition of the faults was such that it was not possible to develop a district to either side of
the main working area, restricting the ability to maintain output and forcing the mine to
develop an alternative area to the east. This resulted in production for 2001 being limited to
less than 31,000t, some 9,000t less than planned.
It was anticipated that the situation would be much improved in 2002 and production was
planned at over 40,000t, however in 2002/03 production is now anticipated to be around
31,400t mainly due to the difficulties in completing the enforced change in working area.
Following 2002/03 it is expected that production will improve to 39,800t in 2003/04 and then
be maintained at around 44,000t/a from 2004/05 onwards.
To enable these forecasted outputs to be achieved the Company is looking to develop an
Auger type machine for coal extraction, the current mining machinery being limited in use
within the anticipated reducing seam section. It is anticipated that the use of an auger will
enable selective mining to be undertaken, greatly reducing the amount of dirt extraction and
therefore substantially reducing coal preparation and dirt handling costs.
4.17.7.2
Development
The future development roadways, which are currently being extended east, will be formed as
an integral part of the production system. The stalls, which are driven 5.79m wide and 14m
apart (albeit that pillar width varies with depth), are supported by steel girders on props. In
the production stalls these supports are salvaged for re-use, the unwanted stalls are, where
possible, filled with discard fed back underground from the surface. The stalls, which are to
be retained for access roadways, are left supported and are fitted out and used for the main
services.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
4.17.7.3
PAGE 271
Risk
The coal has a high sulphur content of 2.8% that restricts its acceptability and price within the
market place.
There is a risk of minor faulting. Due to the relatively thin seam section minor faulting can be
quite disruptive, however, the flexibility of the pillar and stall system of mining is well suited
to minimising the impact on production.
The overall thickness of the seam section is expected to reduce as the workings move south
and east further limiting working height and clearances. The future economic exploitation of
these reserves depends upon the successful development of alternative mining techniques.
4.17.7.4
Long Term Plans
IMC has assessed there to be some 0.18Mt of reserves plus 0.05Mt of resources remaining
within the current planned working area of the Whinmoor Seam potentially supporting four to
five years production at planned levels. No other seams have been identified to maintain
production beyond the exhaustion of the Whinmoor Seam.
4.17.8
OPPORTUNITIES FOR FURTHER INVESTMENT
As in the case of Eckington, the colliery works a simple pillar and stall system planned to
produce around 40,000t/a. The mine therefore has only minimal capital requirements.
However, to enable the forecasted outputs to be achieved the Company is looking to develop
an Auger type machine for coal extraction, the current mining machinery being limited in use
within the anticipated reducing seam section. The mine will therefore be looking towards
Investment Aid to assist in the development and introduction of an auger miner.
There is also potential for further investment schemes associated with the extension of the
mine infrastructure as it progresses east. This may include efficiency schemes such as the
provisioning of manriding facilities and further changes to mining methods with a move to
mechanisation.
As in common with other mine operators concern has been expressed over the difficulty that it
will have in securing the additional 70% of costs should investment aid be available.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 272
410500
2007
Dec
Lic
en
ce
Bo
un
da
ry
Further
Area of
Reserves
410000
2007
May
03
h 20
Marc
Area Worked by Partial Extraction
2003
Aug
Approximate
Landslip Area
2006
July
2007
Jan
03
h 20
Marc
04
h 20
Marc
Hayroyds Colliery
(J. Flack and Sons Ltd)
Whinmoor Seam
Reserves Plan
427000
426500
2004
May
2005
Jan
4
t 200
Sep
426000
(Po Ho
ssi ylan
ble d H
(Po
Su ill
ssi Hoy
rfa Fau
ble lan
ce
Un d H
Po lt
der ill F
siti
gro au
on)
und lt
Po
siti
on)
2005
May
2005
Dec
(Po
ssi Ca
ble wth
Un orn
der e F
gro aul
und t
Po
siti
on
)
5
t 200
Sep
y
ar
nd
ou
eB
nc
ce
Li
(Po Ca
ssi wth
ble or
Su ne F
rfa au
ce
l
Po t
siti
on)
Figure 4-34
I5104C
2006
April
6
t 200
Sep
409500
July 2002
Not to Scale
Hayroyds Colliery: Whinmoor Seam Plan
IMC GROUP CONSULTING LIMITED
DECEMBER 2002
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 273
HAYROYDS COLLIERY APPENDIX
TABLES 1-3
HAYROYDS: TABLE 1.
SEAM SEQUENCE (based upon Hoyland Bank Borehole, see text)
MAIN SEAMS
SEAM THICKNESS
INTERVAL
Note varying interval between the Flockton (and other outcropping coals) and the surface.
Flockton
No details
c. 20m
Fenton (? & Parkgate)
Coal and dirt 2.4m
19m
Green Lane
Coal 0.66m
13m
New Hards
Coal 0.61m
19m
Wheatley Lime
Coal 0.69m
26m
Blocking (Top Silkstone)
Coal 0.46m
38m
Lousey
Coal and dirt 0.39m
4m
Beeston (Black Band)
Coal 0.38m
13m
Whinmoor
Coal and dirt c. 1.20m
The coals below are likely to be thin.
I5104C
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 274
HAYROYDS: TABLE 2
WHINMOOR SEAM: SELECTED NCB BOREHOLES IN SHEET SE21SE
Borehole
or Seam
Report.
Bank
Farm
E.
N.
Bullcliffe
Yard
428502
414846
Clayton
Hall
426668
411778
Dearnlea
426361
411936
426626
414465
Splits and
Thicknesses (cm)
Ash
s-l-d %
Sulphur
s-l-d %
Rank
CRC
Roof
Floor
Notes
Coal
61)
Dirt
43)
Inf. Coal 40) *
Dirt
16)
Coal
60)
Coal
64)
Dirt
35)
Coal
37)*
Dirt
21)
Coal
28)
Coal/Dirt 74 (Top W)
Dirt
165
Coal/Dirt 49 (Low W)
Coal
23)
Dirt
15) (Top W)
Coal
33)
9.9
2.8
401
Sandstone
close
above
Beeston
Sandstone on
Beeston
Mudstone
seatearth
*Beeston/Top
Whinmoor
Seatearth
*Beeston/Top
Whinmoor
Seatearth
Beeston/Top
W 11m split
Seatearth
Seams 2.3m
split; Beeston
c. 8m above
Data not accessed
Mudstone &
siltstone
Sandstone
close
above
Mudstone
Seatearth
Seatearth
Beeston close
above
Data not accessed
Seatearth
Seatearth
Sandstone
Seatearth
Seatearth
Beeston close
above
Seams 2.6m
split
Inf. Coal 28 (Low W)
Emley
Moor 7U
427392
413608
Emley
Moor 9U
Fitting
Shop
426026
412740
425800
411662
427424
410550
Langley
Leisure
Lane
425164
411575
425321
413815
Park Mill
12U
428998
412410
Star Farm
427986
415830
427204
412713
Sycamor
e
I5104C
Data not accessed
11.2
2.7
402
23.4
5.9
-
Coal
28)
Dirt
13) (Top W)
Coal/Dirt 38)
Coal/Dirt 74 (Top W)
Coal/Dirt 66 (Top W)
Coal
Hoyland
Bank
Data not accessed
38 (Low W)
Coal
14)
Dirt
8) (Top W)
Coal
38)
Coal
47 (Low W)
Coal 23 (Top W), part
washed out
Coal
31)
Dirt
2)
Inf Coal 8) Top W
Dirt
22)
Coal
48)
Coal/dirt 79 (Top W)
Dirt
69
Coal/Dirt 56 (Low W)
Coal/Dirt 91 (Top W)
Coal/Dirt 62 (Top W)
10.8
3.9
502
Largely
inferior
10.5
Very
high
3.9
601
16.4
12.6
402
Seatearth
Seatearth
Sandstone
Seatearth
Seatearth
Sandstone
Seatearth
Seatearth
Seatearth
Data not accessed
Siltstones
Seatearth
Data not accessed
Seatearth
Seatearth
Data not accessed
Mudstone
Sandstone
seatearth
5.4
502
Data not accessed
4.8
401
Seatearth
Seams 0.16m
split
Top W/Low
W 2.2m split
Beeston close
above
Beeston close
above
IMC GROUP CONSULTING LIMITED
REVIEW OF THE REMAINING RESERVES AT DEEP MINES FOR
THE DEPARTMENT OF TRADE & INDUSTRY
PAGE 275
HAYROYDS TABLE 3
WHINMOOR SEAM, RESERVES SUMMARY
AREA
RESERVES,
Mt (estimated)
RESOURCES,
Mt (estimated)
MINERAL
POTENTIAL,
Mt (estimated)
IMC COMMENTS
Central area: between
present and recent
workings, limited to the
southeast as detailed in
the text.
0.11*
-
-
*IMC’ s assessment, based on 1m of
coal in the worked section, with a
deduction of c. 50% for pillars and
any geological difficulties.
0.05*-
-
*IMC’ s assessment, as follows.
Thickness, based on 1m of coal in
the worked section (although the
seam is thinning, it is assumed that
this is largely a reduction in the dirt
thickness). Area deduction:
minimum of 70% for pillars and
geological difficulties. Note that this
is notional only, as faults and
possible near-surface features (see
main text) may limit the inbye
extents.
-
-
*IMC’ s assessment, based on 1m of
coal in the worked section, with a
deduction of c. 50% for pillars and
any geological difficulties.
South area: southeast
into the seam-thinning
area. (Six blocks
coloured in light grey
on the plan)
North area: north of
existing workings
(single panel plus area
to west of panel shown
hatched in red).
0.07*
North area extension:
north of the northerly
mine boundary, not laid
out
-
*
-
There is a possibility of Whinmoor
Resources north of the mine
boundary; assessment is beyond the
scope of the present exercise.
TOTALS (estimated)
0.18
0.05*
-
See note above.
Note: no allowance has been made
for local pillar extraction prior to
mine abandonment.
I5104C
Note that the northwestern half of
the panel extends beyond the present
licence boundary: the area beyond is
included here for convenience.
IMC GROUP CONSULTING LIMITED
APPENDIX 1
UK COAL MINING LTD
COLLIERY OPERATIONS
RESERVES ASSESSMENT
PROCEDURE
RESERVES ASSESSMENT PROCEDURE
(OPERATING COLLIERIES)
1.
Introduction
The Reserves Assessment is based on the guidelines proposed by the Institution of
Mining and Metallurgy (IMM) in 1991 and subsequently incorporated into the listing
regulations of the London Stock Exchange.
All reserves are ‘mineable coal reserves’ and are based on in-situ coal sections.
Mining and geological losses are taken into account but not the effects of processing.
In addition to being a statement of recoverable reserves, it also includes an indication
of the perceived geological risk associated with the reserve zones or sub zones.
The Reserves Assessment will be updated on an annual basis, the date of assessment
being the 1st January.
2.
Reserve Plans
Reserve plans will be based on geological structure plans upon which worked areas
and existing roadways have been superimposed.
Where available, projected workings will also be shown on the plans.
In practice the current 5 or preferably 10 year plans are considered suitable as a base
for the reserves plans. The Reserve Plan will show, for each seam, the boundaries of
each reserve zone or sub-zone and their designated identification.
3.
Reserve Zones
Reserves zone are to be based on the tectonic structure of the lease/licence area with
individual zone boundaries being major geological features, lease/licence or planning
consent boundaries.
Each zone will be identified in a logical order, and within a multi-seam situation, each
seam will have the same identification for a specific tectonic block.
Where significant variation in the seam section (e.g. a major split line) occurs within a
reserve zone, the zone can be divided into sub zones with their own identification, that
also makes reference to the full zone identification.
4.
5.
Reserves Area
4.1
For each reserves zone or sub-zone, the gross area (Sqm x 103) of the zone is
to be calculated trigonometrically, planimetered or generated by computer plot.
4.2
A layout factor is then to be applied, dependent on planned methods of
extraction, and subsidence restrictions to give the Net Reserves Area.
4.3
Where a realistic layout can be put in a reserves zone or sub-zone this can be
used as the basis for the calculation.
Base Tonnage
5.1
For each zone and sub-zone:-
5.2
5.3
a)
The average full seam thickness is determined from borehole and, if
available, underground workings data.
b)
The Probable Mined Section (likely working thickness) is estimated,
after discussions with survey, planning and marketing, and the
thickness of coal (including inferior coal) within the Probable Mined
Section is determined and used as a basis for the Gross Tonnage
calculation.
The inherent ash of the coal in the Probable Mined Section is determined from
the borehole and workings data and a standard Specific Gravity (SG) is
assigned to the zone or sub zone as indicated below.
ASH
S.G
Under 6%
1.32
6 to 11%
1.36
Over 11%
1.39
The insitu tonnage (Base Tonnage) for each zone or sub-zone is calculated by:
Net Reserves Area x Coal in probable mined thickness x S.G and is reported to
the nearest ten thousand tonnes (104).
6.
Risk Factor
An assessment of the likely geological losses (e.g. from washouts, steep gradients,
faulting, seam splits) is made based on the intensity and quality of proving of the
tectonic and sedimentary environment of the seam, and each reserves zone or subzone is assigned a tectonic and a sedimentary risk factor.
Each risk factor is assigned a reduction (relaxation) expressed as a percentage, and the
total reduction, being the sum of the tectonic and sedimentary risk factors is applied to
in-situ tonnage to give a recoverable tonnage (relaxed tonnage) expressed to the
nearest ten thousand (104) tonnes.
RISK CATEGORY
REDUCTION %
RISK FACTOR
TECTONIC
SEDIMENTARY
Minimal
1
0
2.5
Slight
2
2.5
5
Moderate
3
7.5
10
Significant
4
15
20
High
5
30+
35+
7.
Reserves Classification
The reserves for each zone or sub-zone are then categorised and placed in the appropriate
reserves classification, which is based on the Institution of Mining and Metallurgy guidelines.
The definitions of Reserves and Resources are shown in Appendix 1.
8.
The resulting reserves are to be reported on form Reserves 1.
This will give risk factor and the rounded tonnages for each reserves zone and reserves
category and also a total reserve for the colliery.
In addition there is a summary of the seam section and the qualities of the probable mined
section which will show:1)
Full seam section (probable mined sections in brackets) including coal, inferior
coal and dirt
2)
Seam thickness
3)
Mined Section Thickness
4)
Thickness of Coal and Inferior Coal in Mined Section
5)
Percentage by weight of dirt in mined section
6)
Percentage of ash in mined section
7)
Clean coal ash %
8)
Clean coal sulphur %
9)
Clean coal chlorine %
The form Reserves 1 will be signed and dated to show when prepared and will also show the
date to which the assessment is assigned.
DEFINITIONS
1.
Reserve
A reserve is the portion of a resource that it is considered can be extracted under
current economic conditions.
Major access development is not generally required or if required, a full evaluation has
been undertaken, and the seam and area are included in the lease/licence and have the
benefit of planning permission.
1a.
Proved Reserve
A reserve zone or sub-zone in which sufficient data is available to predict with
a high degree of confidence, the tectonic and sedimentary environment of the
seam, (risk factors less than or equal to 2) and the seam properties are known
to be of an acceptable quality.
Additionally the proposed method of extraction is known and has been tested
in a comparable geological environment.
1b.
Probable Reserve
A reserve zone or sub-zone in which
a)
Insufficient data is available to predict with a high degree of confidence
the tectonic and/or sedimentary environment of the seam (one or both
risk factors is 3 or above) or the seam properties.
or
b)
2.
Sufficient data is available to normally allow the zone or sub-zone to be
included in the Proved category but the method of extraction has not
been fully tested in a comparable geological environment.
Resource
A resource is an area of mineral in which there is an economic interest, with seam
properties and geological environment known to a specified degree.
Major access development is required and has not been fully investigated or evaluated.
The seam and area are included in the lease/licence area and have the benefit of
planning permission.
2a.
Measured Resource
Sufficient data is available to allow the tectonic and sedimentary environment to be predicted
with a reasonable degree of confidence. (Risk factors are less than or equal to 2)
Sufficient data is also available to predict the seam properties.
2b.
Indicated Resource
A reserve zone or sub-zone in which the sedimentary and tectonic
environment, and seam properties cannot be predicted with the same degree of
certainty as a Measured Resource. (One or both risk factors is 3 or above)
3.
Mineral Potential
a)
Any area of a seam that could fall into a Reserve or Resource category when
planning permission and lease/licence has been obtained.
b)
A reserve zone within which seam continuations at an economic thickness are
interpolated but no direct or very limited proving of the geological
environment and seam properties has been undertaken.
GLOSSARY OF TERMS
Anticline. A fold in the rock volume along which the beds are up-arched.
Arcuate Fault. Normal fault (see Faults, fault throws) bent like a bow.
Aquifer. A rock sequence that contains water in a quantity that has commercial value. The
term is sometimes used loosely in mining, to mean a rock sequence that contains water
sufficient in quantity to cause underground problems.
Bolting; rock bolting, roof bolting. A method of supporting an excavation, in which the
adjacent rock is strengthened by steel bolts and cementing material.
Carboniferous. A geological period that lasted from c. 350 to c. 290 million years ago. It was
characterised by widespread coal formation on continents that are now in the northern
hemisphere.
Cleat. Cleavage in coal: Cleavage is the preferred plane of parting in a rock due to the
alignment of platy minerals by tectonic stress or in a mineral as a result of planes of weakness
due to its atomic structure.
Coal Measures. Geological sequences that are coal-bearing. In the UK, the term applies to
particular sequences of Upper Carboniferous age, individually named as Lower, Middle and
Upper Coal Measures, the Lower being the oldest sequence.
Continuous miner, JCM. A machine which has rotating disks in which there are cutting
tools. These disks are normally rotate on a vertical plane cutting the mineral, normally coal or
soft stone. The machine can in theory continue to advance forward whilst driving the
roadway, normally rectangular cross-section. In practice it has to stop to allow roadway
support to be completed and the extension of conveyor systems. JCM is used to indicate that
it is a continuous miner produced by JOY MANUFACTURING.
Crosscut. A short mine roadway linking two main roadways, allowing travel between the
intake and return ventilation circuits.
Development. The accessing drivages, actual or planned, that open up the reserve areas for
extraction.
Dip; bedding dip, fault plane dip. Dip is the angle, measured from the horizontal, of any
geological surface.
Dirt, dirt layers. In UK coal mining, dirt is any rock that has an ash content >40%.
Displacement. The full distance across which a bed is separated on each side of a fault.
Displacement is to be distinguished from throw (which is simply the vertical component of
the offset): displacement = throw / sine (fault plane dip).
Drift, cross-measures drift. A drift is a mine drivage that crosses from one geological
horizon to another.
Drivage. A main mine roadway.
Face, faceline, advancing face, retreat face. A coal face is the exposed section of coal at the
place of production in a longwall or other mining system. An advancing face travels forwards,
usually closely behind the associated development roadways (see main gate and tail gate), and
therefore proves the ground in detail as it moves forward. A retreating face extracts the coal
between pre-driven roadways, and is therefore at less geological risk.
Faults, fault throws. Faults are planar discontinuities in the rock volume, along which
geological sequences are displaced. The throw of a fault is the generalised elevation
difference of the same bed on the opposing sides of the fault: see displacement. Faults with
throws that are significantly greater than coal seam thickness invariably lead to abandonment
of a coal face. If smaller faults are mined through, this produces excess dirt in the run-of-mine
product, and there may also be support problems.
Fault zone. A complex array of related faults.
FSV. Free-steering vehicle: an independently-powered rubber-tyred vehicle for use
underground for transport of men or materials.
Gate, loader gate, tail gate. A mine roadway associated with a coal face. The loader (or
main) gate is normally used for intake ventilation and coal clearance, and the tail (or supply)
gate for transport of materials and return ventilation.
Goaf. The worked volume, including the immediately collapsed ground, behind a coal face;
also known as the waste.
Horizon, stratigraphical horizon. In a sequence of sedimentary rocks (such as the Coal
Measures), a particular layer of rock, or a particular depositional event, that is consistent
enough to be recognised over a significant area.
IFS (Immediate Forward Support). Face support system that allow the powered supports to
be advanced to support the newly exposed roof immediately behind the shearing disc.
Igneous features. Rocks and structures that result from volcanic or related processes.
Inbye. The direction inwards, or the overall inner areas of a mine.
Intake. The fresh air circuit of a mine ventilation system.
Interaction. The stress effects of one mine excavation upon another.
Interval. In mining, the thickness of the strata between one horizon and another.
JCM. See continuous miner.
Longwall. A coal face with a length usually measured in high 10’ s or low 100’ s metres.
Methane. Methane (CH4) is a gaseous hydrocarbon that occurs naturally in the Coal
Measures. It is liberated from coal seams during the mining process. The methane content of a
coal seam is measured typically in cubic metres per tonne.
Methane drainage. A system whereby methane is drained from the strata via boreholes, and
then piped to the surface for disposal.
Mudstones. A sedimentary rock composed mainly of mineral grains that are of mud size.
Outbye. The direction outwards, or the overall outer areas of a mine.
Panel. A longwall face together with its main gate and tail gate.
Permian. A geological period that lasted from c. 290 to 250 million years ago.
Pillar, pillar edge. (a) A volume of coal left unmined, for the purposes of supporting other
mining infrastructure or features at the surface. A pillar edge is the margin of a pillar. (b) A
small column of coal taken underground for analysis.
Powered Supports. Longwall face supports which are advanced and set utilising hydraulic
power.
Reserves and Resources definitions.
Reserves: measured mineral resources for which detailed technical and economic studies
have demonstrated that extraction can be justified at the time of determination, and under
specific economic conditions. Reserves may be categorised as proven, or probable, depending
upon the degree of assurance of mining characteristics, and the probability that predicted
levels of extraction can be achieved.
Resources: the proportion of the mineral resource that has not been sufficiently appraised to
demonstrate them as proven or probable reserves. They may be defined as measured or
indicated mineral resources, dependent on the degree of certainty on the physical character,
shape, quality and mineral content of the assessed zone.
Return. The used air circuit in a mine ventilation system.
Road, roadway. A mine tunnel, usually applied to one that lies within one seam (see cross
measures drift).
Roadheader. A track-mounted cutter/loading machine with an articulated boom with rotary
cutting head, used for the mechanised drivage of mine roadways.
Roof; higher roof, immediate roof. Roof: a term applied either to the observable rock face
overlying an underground excavation, or to the greater volume of rock lying above that.
Higher roof: a term usually taken to mean the ground above the active caving height.
Immediate roof: a term usually taken to mean the observable rock, or the ground within the
active caving height.
Run-of-mine, ROM. Output from the mine before preparation.
Sandstones, sandstone-filled channel systems. Sandstones are sedimentary rocks in which
the constituent mineral grains are mostly sand-sized. Most sandstones in the Coal Measures
were deposited in river channels and related environments. Rivers invaded during times of
coal (then in the state of peat) accumulation, giving seam splits, and also at other times, when
coal was not accumulating. The sandstones can be mapped to reveal the river system patterns
(usually deltaic). Sandstones contribute many problems to mining, particularly regarding roof
support, and give hard cutting and greater frictional ignition risks where present on a coal
face.
Siltstones. Siltstones are sedimentary rocks in which the constituent mineral grains are mostly
silt-sized.
Seam, coal seam. A coalbed, or a composite group of coalbeds and their intervening dirt
layers, that is regionally recognisable and mappable.
Seam splits. See sandstones, above. Seam splits are where a coal seam divides into two (or
sometimes more) individual coalbeds. They can be mapped from a mininum interval (where
the fill is generally mudstone) through to a maximum (typically around 10m) which will
commonly contain sandstones. The rate of opening of a seam split varies, and may be rapid
(opening to several metres interval, over a distance of a few 10’ s metres). A significant seam
split will mean that face equipment, designed for a united seam, will become unsuitable.
Seismic surveys. These are methods of determining the geological structure (faults, horizon
elevations) using energy sources and receivers, to assess the pathways of acoustic waves
through the rock volume. A 2D surface seismic survey is one where the energy sources and
receivers are arranged along a line, and the interpreted result is a 2D profile through the
ground beneath the line. A 3D surface seismic survey uses a grid of source and receiver lines,
allowing computation of a 3D result. In-seam seismic surveys place the energy sources and
receivers in the coal seam underground.
Shear. A full cut of coal from one end of the face to the other.
Shearer. A machine for cutting coal on a longwall face.
Splay. A lesser fault diverging from a greater fault, and kinematically associated with it.
Spontaneous combustion. Ignition of a substance (such as coal) without an external ignition
source. Oxidation of coal promotes its spontaneous combustion.
Stone, stone drivage. Stone is a general mining term for any rock other than coal. A stone
drivage is one that is made through stone (not necessarily cross-measures, q.v.).
Strata. The overall sequence of sedimentary rocks.
Structure; structural geology; seam structure. (a). Structural geology is that part of the
subject that deals with the geological deformation of the overall rock volume, irrespective of
the type of rock involved. The main features relevant to mining are faults, folds and joints
(cleat in coal). The term “ the structure” is used in a general sense to mean the local pattern of
faults and folds. (b). Seam structure, in coal mining, refers to the layering of different types of
coal and dirt that make up a seam.
Stub. This is a short length of roadway, which is driven to facilitate the commencement of
drivage from this point without causing any un-due delay. The equipment required can be
installed without conflict with any ongoing mining opertions.
Support. In a mine, the term can mean particular hardware items (“ the supports” ), or the
overall extraction and engineering system, whereby the excavation, and its roof, sides, and
floor are effectively maintained.
Triassic. A geological period that lasted from c. 250 to c. 205 million years ago.
Washouts. Washouts occur where a river of Coal Measures times eroded into an underlying
coal (then peat). Washouts are typically elongate in plan, with lengths and widths measuring
metres to 100’ s metres. Within a washout, the coal is partly or entirely replaced by other
sediment, often sandstone. Apart from the problems resulting from loss of coal, washouts
present a higher frictional ignition risk, together with excess wear on machine picks.
Zone, resource zone. An area of coal resources wherein the seam has a similar seam /
coalbed character throughout. Zone boundaries may therefore be seam splits, or lines
denoting significant seam thickness variations. Important faults also form zone boundaries.

Similar documents