technical report - Canada Zinc Metals Corp.

TECHNICAL REPORT:
GEOLOGY, DIAMOND DRILLING AND
PRELIMINARY RESOURCE
ESTIMATION, AKIE ZINC-LEADSILVER PROPERTY, NORTHEAST
BRITISH COLUMBIA, CANADA
Omenica Mining Division
NTS 94F/7W
Latitude 57o22’ N
Longitude 124o51’ W
Submitted to:
Mantle Resources Inc.
May 31, 2008
Effective Date: March 29, 2008
Qualified Persons:
Donald G. MacIntyre, P.Eng.
Robert C. Sim, P.Geo
TABLE OF CONTENTS
Table of Contents...........................................................................................................................2
List of Figures ................................................................................................................................4
List of Tables .................................................................................................................................5
List of Photos .................................................................................................................................6
1.0 Summary ..................................................................................................................................7
2.0 Introduction and Terms of Reference ......................................................................................9
3.0 Reliance on other Experts ......................................................................................................10
4.0 Property Description and Location ........................................................................................10
5.0 Accessibility, Climate, Local Resources, Infrastructure and Physiography..........................15
6.0 History....................................................................................................................................15
6.1 Gataga District ...................................................................................................................15
6.2 Akie Property .....................................................................................................................17
7.0 Geological Setting..................................................................................................................21
7.1 Lithostratigraphic Units .....................................................................................................22
7.1.1 Proterozoic to Early Cambrian - Windermere Supergroup.........................................22
7.1.2 Early to Late Cambrian - Gog Group .........................................................................22
7.1.3 Cambrian to Ordovician - Kechika Group..................................................................23
7.1.4 Early to Late Ordovician - Skoki limestone ...............................................................23
7.1.5 Ordovician to Early Devonian - Road River Group ...................................................23
7.1.8 Early to Middle Devonian - carbonate reefs ...............................................................26
7.1.9 Middle Devonian to Mississippian - Earn Group .......................................................27
7.1.10 Mississippian to Triassic - chert and siltstone ..........................................................28
7.2 Structure.............................................................................................................................28
7.3 Property Geology ...............................................................................................................29
8.0 Deposit Types ........................................................................................................................31
9.0 Mineralization ........................................................................................................................33
9.1 Lithostratigraphic and mineralized units intersected in drilling ........................................34
9.1.1 Upper Gunsteel shale ..................................................................................................34
9.1.2 Lower Gunsteel shale..................................................................................................34
9.1.3 Cardiac Creek unit ......................................................................................................34
10.0 Exploration...........................................................................................................................35
10.1 Soil Geochemistry............................................................................................................35
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10.1.2 Akie Main Grid .........................................................................................................37
10.1.2 Akie Reconnaissance Grid:.......................................................................................38
10.2 Lithogeochemistry ...........................................................................................................38
10.3 Geophysics.......................................................................................................................39
11.0 Drilling.................................................................................................................................40
11.1 Inmet drill programs (1994-1996) ...................................................................................40
11.2 Mantle Resources drill programs (2005-2007) ................................................................43
12.0 Sampling Method and Approach .........................................................................................53
13.0 Sample Preparation, Analyses and Security ........................................................................54
13.1 Site Visit...........................................................................................................................54
13.2 Sample Preparation and Analysis ....................................................................................54
13.2.1 Sample Preparation ...................................................................................................55
13.2.2 Control Sample Performance....................................................................................56
13.3 Conclusions......................................................................................................................66
14.0 Data Verification..................................................................................................................67
15.0 Adjacent Properties..............................................................................................................68
15.1 Fluke ................................................................................................................................68
15.2 Elf.....................................................................................................................................68
16.0 Mineral Processing and Metallurgical Testing ....................................................................68
17.0 Mineral Resource and Mineral Reserve Estimates ..............................................................69
17.1 Introduction......................................................................................................................69
17.2 Geologic Model, Domains and Coding ...........................................................................70
17.3 Available Data .................................................................................................................71
17.4 Bulk Density Data............................................................................................................71
17.5 Compositing.....................................................................................................................72
17.6 Exploratory Data Analysis...............................................................................................72
17.6.1 Basic statistics by Domain ........................................................................................72
17.6.2 Contact Profiles.........................................................................................................73
17.6.3 Conclusions and Modeling Implications ..................................................................73
17.7 Evaluation of Outlier Grades ...........................................................................................73
17.8 Variography .....................................................................................................................74
17.9 Model Setup and Limits...................................................................................................75
17.10 Interpolation Parameters ................................................................................................75
17.11 Validation.......................................................................................................................76
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17.11.1 Visual Inspection ....................................................................................................76
17.11.2 Model Checks for Change of Support ....................................................................77
17.11.3 Comparison of Interpolation Methods ....................................................................77
17.11.4 Swath Plots (Drift Analysis) ...................................................................................79
17.12 Resource Classification..................................................................................................81
17.13 Mineral Resources .........................................................................................................82
18.0 Other Relevant Data and Information..................................................................................83
19.0 Interpretation and Conclusions ............................................................................................83
20.0 Recommendations................................................................................................................84
21.0 References............................................................................................................................86
22.0 Certificates of Authors.........................................................................................................90
Appendix A. Sedex Deposit Model Description..........................................................................92
LIST OF FIGURES
Figure 1. Location of the Akie property relative to major transportation routes and population
centres in British Columbia. ................................................................................................11
Figure 2. Location of the Akie property relative to major tectonic and physiographic belts in
British Columbia .................................................................................................................12
Figure 3. Claim map, Akie property. ...........................................................................................14
Figure 4. Generalized geology of the Gataga mineral district showing location of major
prospects. .............................................................................................................................16
Figure 5. Geology of the Akie River area....................................................................................20
Figure 6. Stratigraphic column, Akie River district.....................................................................21
Figure 7. Genetic model for formation of SEDEX deposits in the Gataga District.....................30
Figure 8. Soil geochemistry, Akie Property.................................................................................36
Figure 9. Geology and 1994-1996 drill hole locations, Akie property.......................................39
Figure 10. Idealized geological cross section 3400S, Akie Property. .........................................44
Figure 11. Cardiac Creek Zone pierce points in vertical long section view. ...............................45
Figure 12. Drill hole plan showing location of 2005-2007 drill holes.........................................48
Figure 13. Detailed drill hole plan, Cardiac Creek zone..............................................................49
Figure 14: Idealized stratigraphic section of Akie property down hole geology. ......................50
Figure 15. STD PB109.................................................................................................................57
Figure 16. STD PB 110................................................................................................................58
Figure 17. STD PB 111................................................................................................................59
Figure 18. STD PB 112................................................................................................................60
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Figure 19. STD PB 118................................................................................................................61
Figure 20. STD PB 123................................................................................................................62
Figure 21. Sample blank performance .........................................................................................63
Figure 22. Core duplicate sample performance ...........................................................................64
Figure 23. Pulp duplicate sample performance - Zn....................................................................65
Figure 24. Pulp duplicate sample performance - Pb ....................................................................66
Figure 25. Minzone domain – example 1 ....................................................................................69
Figure 26. Minzone domain – example 2 ....................................................................................70
Figure 27. Herco plot - Zn ...........................................................................................................77
Figure 28. Grade-tonnage curve - Zn...........................................................................................77
Figure 29. Grade-tonnage curve – Pb ..........................................................................................78
Figure 30. Grade-tonnage curve - Ag ..........................................................................................79
Figure 31. Swath plot - Zn ...........................................................................................................80
Figure 32. Swath plot - Pb ...........................................................................................................80
Figure 33. Swath plot - Ag...........................................................................................................81
Figure 34. Distribution of inferred mineral resources above base case cut-off grade of 5% Zn.
..............................................................................................................................................82
Figure 35. Base case resource estimate showing proposed in-fill drill holes. .............................84
LIST OF TABLES
Table 1. Inferred Mineral Resource Estimate ...............................................................................8
Table 2. Akie Property Mineral Tenures (Source: Mineral Titles On-Line, April 29, 2008)......13
Table 3. Summary of Inmet and Mantle drill holes, Akie Property. ...........................................41
Table 4. Summary of significant drill intersections, Akie property. ...........................................45
Table 5. Summary of Basic Statistics of Samples Inside Minzone Domain ...............................71
Table 6. Summary of Basic Statistics of Composited Samples Inside Minzone Domain ...........72
Table 7. Summary of Basic Statistics of Composited Samples Outside of Minzone Domain ....73
Table 8. Outlier Grade Analysis Inside Minzone Domain ..........................................................74
Table 9. Variogram Parameters – Zinc ........................................................................................74
Table 10. Variogram Parameters – Lead .....................................................................................74
Table 11. Variogram Parameters – Silver....................................................................................74
Table 12. Block Model Limits .....................................................................................................75
Table 13. Interpolation Parameters ..............................................................................................76
Table 14. Inferred Mineral Resource ...........................................................................................82
Table 15. Estimated Cost of the Recommended Program ...........................................................85
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LIST OF PHOTOS
Plate 1. View northwest showing location of the Cardiac Creek showing, surface trace of
mineralized horizon and upslope drill sites as of the end of 2005.........................................8
Plate 2. Cardiac Creek discovery showing.. ................................................................................32
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1.0 SUMMARY
The Akie property was originally staked by Rio Tinto Exploration in the early 1980’s as the
Dog claims (Hodgson, 1980). Although Rio Tinto obtained anomalous metal concentrations in
soil samples, only nodular barite mineralization was found on the property and the claims were
allowed to lapse. The area was restaked by Ecstall Mining Corporation, the current owners of
the claims and a wholly owned subsidiary of Mantle Resources. Inc.
The Cardiac Creek showing on the Akie property is the most recent discovery in the Gataga
District. It was located by Metall Mining Corporation (now Inmet Mining Corporation) in 1994
while exploring ground optioned from Ecstall Mining Corporation. This showing was drill
tested in 1994, 1995 and 1996. In that time period a total of $3,798,173.43 was filed for
assessment credit. Most of this cost was related to completion of 13,685.5 metres of diamond
drilling in 29 holes. Based on this drilling Inmet Mining Corporation calculated a pre NI43-101
resource estimate of 12 million tonnes grading 8.6% Zn, 1.5% Pb and 17.10 grams per tonne
Ag. In 2005 Mantle Resource Corporation optioned the property from Ecstall and between
2005 and 2007 drilled an additional 27 holes totaling 13,405.5 metres. Most of this drilling
focused on the Cardiac Creek zone. In 2007, Mantle obtained control of Ecstall and made all
remaining option payments to Inmet on behalf of Ecstall to acquire a 100% interest in the Akie
property.
The Cardiac Creek deposit is situated approximately half way between the Fluke and Elf
deposits. Like others in the district the mineralization consists of laminated to massive pyrite
and barite with local finely laminated bands of sphalerite and galena (Baxter et al., 1996;
Paradis et al., 1998). The deposit occurs within a southwest dipping panel of Gunsteel
formation cherty argillites and shale which structurally underlies a thrust panel of Silurian
siltstone. Drilling to date indicates the deposit is sheetlike with a strike length of 1,600 metres, a
dip extent of at least 800 metres and true thicknesses up to 30 metres.
The mineral resource estimate presented in this report has been generated from drill hole sample
assay results and the interpretation of a geologic model which relates to the spatial distribution
of zinc, lead and silver. Interpolation characteristics have been defined based on the geology,
drill hole spacing and geostatistical analysis of the data. The resources have been classified by
their proximity to the sample locations and are reported, as required by NI43-101, according to
the CIM standards on Mineral Resources and Reserves. Extensive analysis of the drill sample
database shows that it is sound and reliable for the purposes of resource estimation. The
resource model has been developed in accordance with accepted industry standards resulting in
a mineral resource defined within the inferred category.
The resources, presented in the Table 1, are summarized for comparison purposes at a series of
cut-off grades. Highlighted in the table is the “base case” cut-off grade of 5% zinc for the
sulphide resource which is based on assumptions derived from operations with similar
characteristics, scale and location. This report includes estimates for mineral resources. There
are no mineral reserves prepared or reported.
In the opinion of the writers, the Akie property is of sufficient merit to justify additional
exploration and development expenditures. Metal zoning studies, structural modeling and the
results of previous drilling suggest the Cardiac Creek deposit is of sufficient size and grade to
be potentially economic as a mining operation. A 7,000 metre infill drilling program is
recommended to bring the inferred resource into the indicated category. Additional
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metallurgical testing and environmental studies are also recommended. The cost to complete the
recommended work program is $6,187,500.
Table 1. Inferred Mineral Resource Estimate
Cut-off Grade
(Zn%)
ktonnes
Zn (%)
Pb (%)
Ag (gpt)
2
50,874
5.28
1.00
9.6
3
37,683
6.25
1.22
11.0
4
30,595
6.89
1.36
12.0
5
23,595
7.60
1.50
13.0
6
17,051
8.41
1.68
14.2
7
11,841
9.26
1.86
15.4
(1)
(2)
“Base case” cut-off grade of 5.0%Zn highlighted in table.
Resource are not mineral reserves as the economic viability has not been
demonstrated.
Plate 1. View northwest showing location of the Cardiac Creek showing, surface trace of
mineralized horizon and upslope drill sites as of the end of 2005. Photo from report by
Vanwermeskerken and Metcalfe, 2006
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2.0 INTRODUCTION AND TERMS OF REFERENCE
This technical report is being prepared at the request of Mr. John Fraser P.Geo. (B.C.), a
director of Mantle Resources Inc. a publicly traded company listed on the TSX Venture
Exchange. This report is an expansion of an earlier NI43-101 compliant geological report on the
Akie Property (MacIntyre, 2005), a previous report prepared by Paul Baxter for Inmet Mining
Corporation (Baxter, 1996c) and dated December 1996 and recent assessment reports
summarizing the results of the 2005 and 2006 drilling programs (Vanwermeskerken and
Metcalfe, 2006; Johnson and Metcalfe, 2007). The writers have been asked to review all data
pertaining to the property and to prepare a report that summarizes the results of drilling up to
the end of 2007 and to prepare a preliminary mineral resource estimation.
Mantle Resources Ltd. (Mantle) commissioned Don MacIntyre, D.G. MacIntyre & Associates
Ltd. and Robert Sim, SIM Geological Inc. to provide an independent Qualified Person’s
Review and Technical Report in support of a preliminary mineral resource estimate for the Akie
zinc-lead-silver deposit located in north-central British Columbia, Canada. Don MacIntyre,
Ph.D., P.Eng. an independent consultant prepared an earlier NI43-101 qualifying report on the
Akie Property (MacIntyre, 2005) and much of this earlier material has been updated and
incorporated into this report. Dr. MacIntyre has extensive experience in the Gataga mineral
district and SEDEX deposits in general, much of which relates to geological mapping and
mineral deposit studies done on behalf of the B.C. Geological Survey between 1979 and 1981.
Robert Sim, P.Geo, an independent consultant, served as a Qualified Person responsible for the
preparation of the sections 13, 14 and 17 of this Technical Report as defined in National
Instrument 43-101, Standards of Disclosure for Mineral Projects (NI 43-101), and in
compliance with Form 43-101F1 (the Technical Report). Mr. Sim is a geologist with over 24
years of experience primarily in base and precious metals exploration, operations, resource
modeling and feasibility-level evaluations. Mr. Sim has direct experience working on the Pend
Oreille lead-zinc deposit in NE Washington, USA . Mr. Sim received assistance in the
generation of the resource model and data validation from Geostatistician, Bruce Davis, Ph.D.,
FAusIMM, BD Resource Consulting Inc.
As stated above, this technical report has been prepared in compliance with the requirements of
National Instrument 43-101 and Form 43-101F1 and is intended to be used as supporting
documentation to be filed with the British Columbia Securities Commission and the TSX
Venture Exchange. The purpose of this filing is to document a preliminary mineral resource
estimation for the property.
Information and data for this independent review was provided by Nick Johnson, Project
Geologist for Mantle who has been managing the site operations at Akie since 2006. Robert
Sim conducted a site visit to the Akie property in October 2007 during which he reviewed
drilling activities and related geological issues with Mantle personnel Nick Johnson, John
Fraser (Director) and Jim Mustard (President).
Neither Robert Sim or Don Macintyre is an associate or affiliate of Mantle, or of any associated
company. Fees paid for this technical report are not dependent in whole or in part on any prior
or future engagement or understanding resulting from the conclusions of this report.
In preparing this report, Sim and Macintyre reviewed the geological reports and maps and
miscellaneous technical papers listed in the References section at the conclusion of this report
as well as consulted with experienced Mantle personnel. Information used in the preparation of
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this report includes a number of internal company reports not available to the public. These
reports contained detailed information on the results of diamond drilling completed on the
property. Citations for these reports are contained in the Reference section of this report. The
property was visited by D.G. MacIntyre on August 26, 2005 and by Rober Sim on October 1617, 2007. D.G. MacIntyre also did geological mapping in the vicinity of the Akie claims in
1980 and 1981 while employed by the B.C. Ministry of Energy and Mines (MacIntyre, 1980,
1981, 1981a, 1992, 1998).
The mineral resource estimation presented in this report is based on information known to Sim
and Davis as of March 29, 2008. This report includes estimates for mineral resources. There
are no mineral reserves presented in this report.
Units of measure in this report are metric; monetary amounts referred to are in Canadian
dollars.
The effective date of this technical report is March 31, 2008.
3.0 RELIANCE ON OTHER EXPERTS
This report is based on a review of previous reports filed for assessment credit with the B.C.
Ministry of Energy and Mines and on internal company reports, database files, core photos and
original assay certificates supplied by Mantle Resources Inc., the issuer. Most of the work done
to date on the Akie property has been filed for, or will be filed for assessment credit and much
of this information is available for download as PDF documents using the Assessment Report
Indexing System (ARIS) of the B.C. Ministry of Energy and Mines. The authors are satisfied
that the data provided for this report was collected and processed in a professional manner
following industry best practices applicable at the time, and that the historical data gives an
accurate indication of the nature, style and possible economic value of known mineral
occurrences on the property. In particular, the authors have relied on reports prepared by Inmet
Mining and Mantle Resources, the issuer, and these have been cited throughout this technical
report. These reports include those prepared by P. Baxter (Baxter, 1995, 1996, 1996a, 1996b),
for Inmet and M. Vanwermeskerken, P. Metcalfe (Vanwermeskerken and Metcalfe, 2006) and
N. Johnson (Johnson and Metcalfe, 2007) for Mantle. The QP’s of this technical report consider
these authors to be competent professionals and see no reason to believe that the information
presented in these reports not to be correct but have not performed and independent review.
Details of the status of tenure ownership on the Akie property were derived from a series of
press releases issued by Mantle Resources Inc and on personal communication with company
representatives. Although the writers have no reason to believe this information is inaccurate a
detailed audit of the legal agreements between Mantle Resources and Ecstall Mining has not
been done and the writers are relying solely on information that has been made available to the
public and on internal company reports.
4.0 PROPERTY DESCRIPTION AND LOCATION
The Akie property consists of 22 contiguous legacy four-post mineral tenures (Akie 1-19, 21-22
and 25) encompassing a surface area of approximately 6400 hectares (Table 1) and a 18cell
claims staked on-line to cover adjoining areas of interest (AOI). The claims are owned 100% by
Ecstall Mining Corporation, a wholly owned subsidiary of Mantle Resources Inc. According to
Johnson and Metcalfe (2007) Mantle has also acquired the HSH group of mineral tenures,
which cover ground presently occupied by their exploration camp and contiguous with the
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AKIE AX 3 tenure (Ecstall). Notwithstanding that the HSH group lies outside the 2 km area of
interest specified in the Option Agreement, Mantle interprets these tenures as part of the option
agreement. The total area covered by the mineral tenures listed in table 1 is 10,205.46 hectares.
All mineral tenures are in good standing until December 20, 2017.
Figure 1. Location of the Akie property relative to major transportation routes and population
centres in British Columbia.
The Akie claims are located in the western ranges of the Northern Rocky Mountains
physiographic region of the Province of British Columbia, Canada within National Topographic
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System sheet 094F/7W and across Terrain Resource Integrated Management (TRIM) map
sheets 094F036, 094F037 and 094F046. The claims cover the Cardiac Creek showing
(MINFILE no. 094F 031) which is located at Universe Transverse Mercator (UTM) coordinates 389074E, 6360045N using North American Datum (NAD) 83, or latitude 57o22’11’’N
longitude 124o50’40”W. The nearest town is McKenzie B.C., which is located 250 kilometres
southeast of the property (Figure 2).
Figure 2. Location of the Akie property relative to major tectonic and physiographic belts in
British Columbia .
The writers have checked the status of mineral tenures that comprise the Akie property by
cross-referencing claim names and tenure numbers with those in the B.C. Ministry of Energy
and Mines mineral tenure database using the Mineral Titles On-Line system. The names and
numbers supplied by the issuer are the same as those in the database. To the writers knowledge
the Akie claims have not been legally surveyed.
According to the B.C. Ministry of Energy and Mines Mineral Titles On-Line database the
claims listed in Table 1 are owned 100% by Ecstall Mining Corporation (client number 107445)
a publicly traded company listed on the TSX Venture exchange. Ecstall Mining Corporation is a
wholly owned subsidiary of Mantle Resources Inc. As announced in a press release date April
5, 2007, Mantle acquired a 100% registered interest in the Akie Property by making final option
payments on behalf of Ecstall to Inmet Mining Corporation to acquire their 60% registered
interest in the property. As a consequence of this transaction Ecstall became the registered
owner of a 100% royalty free interest in the Akie claims that were included in their option
agreement with Inmet.
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Table 2. Akie Property Mineral Tenures (Source: Mineral Titles On-Line, April 29, 2008)
No
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Tenure Type
Claim Name
Map
Number
Good To Date
115751
Legacy
AKIE 1
094F036
2017/dec/20
75.00
240792
115752
Legacy
AKIE 2
094F036
2017/dec/20
150.00
240793
115753
Legacy
AKIE 3
094F036
2017/dec/20
75.00
324822
225641
Legacy
AKIE 4
094F036
2017/dec/20
100.00
324823
225642
Legacy
AKIE 5
094F036
2017/dec/20
400.00
324824
225643
Legacy
AKIE 6
094F036
2017/dec/20
150.00
324825
225644
Legacy
AKIE 7
094F036
2017/dec/20
500.00
327931
225670
Legacy
AKIE 8
094F036
2017/dec/20
150.00
327932
225671
Legacy
AKIE 9
094F036
2017/dec/20
300.00
327933
225672
Legacy
AKIE 10
094F036
2017/dec/20
100.00
329534
229476
Legacy
AKIE 11
094F036
2017/dec/20
400.00
329535
229477
Legacy
AKIE 12
094F036
2017/dec/20
500.00
329536
229478
Legacy
AKIE 13
094F036
2017/dec/20
500.00
329537
229479
Legacy
AKIE 14
094F036
2017/dec/20
375.00
329538
229480
Legacy
AKIE 15
094F036
2017/dec/20
150.00
329539
229481
Legacy
AKIE 16
094F036
2017/dec/20
200.00
330626
229482
Legacy
AKIE 17
094F036
2017/dec/20
400.00
333352
225751
Legacy
AKIE 21
094F036
2017/dec/20
450.00
333353
225752
Legacy
AKIE 22
094F036
2017/dec/20
225.00
333356
225755
Legacy
AKIE 25
094F046
2017/dec/20
500.00
338283
232399
Legacy
AKIE 18
094F037
2017/dec/20
400.00
338284
225775
Legacy
AKIE 19
094F037
2017/dec/20
300.00
517839
NA
Cell
CURE
094F
2017/dec/20
34.88
520476
NA
Cell
AKIE 30
094F
2017/dec/20
436.14
523916
NA
Cell
AKIE FR.
094F
2017/dec/20
87.18
523920
NA
Cell
AKIE FR 2
094F
2017/dec/20
17.44
526549
NA
Cell
AKIE AX 1
094F
2017/dec/20
436.57
526550
NA
Cell
AKIE AX 2
094F
2017/dec/20
436.75
526551
NA
Cell
AKIE AX 3
094F
2017/dec/20
436.98
529015
NA
Cell
AKIE 31
094F
2017/dec/20
366.10
529025
NA
Cell
AKIE 31A
094F
2017/dec/20
17.44
529026
NA
Cell
AKIE 31B
094F
2017/dec/20
17.43
546692
NA
Cell
AKIE 41
094F
2017/dec/20
436.54
546693
NA
Cell
AKIE 40
094F
2017/dec/20
348.69
549880
NA
Cell
unnamed
094F
2017/dec/20
366.47
549884
NA
Cell
unnamed
094F
2017/dec/20
52.33
549885
NA
Cell
AKIE 20
094F
2017/dec/20
87.26
552382
NA
Cell
AKIE 23
094F
2017/dec/20
17.44
555813
NA
Cell
HSH
094F
2017/dec/20
192.36
557781
NA
Cell
ROME
094F
2017/dec/20
Tenure Number
Tag Number
240791
Area
17.47
10,205.46
As shown in Figure 3, mineral tenures that comprise the Akie property are adjacent to claims
held by Mantle Resources Inc. which are located west of the property and by claims held by the
Cirque Operating Corporation which cover the Fluke and Elf properties to the north and south .
The writers are not aware of any environmental liabilities associated with the Akie property.
There are no old workings on the property and the only indications of previous exploration
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activity are drill sites cut into heavily timbered slopes above the massive sulphide horizon and
some old tent frames near the core storage area.
Figure 3. Claim map, Akie property. Map prepared by the D.G. MacIntyre using data from the
B.C. Ministry of Energy and Mines Mineral Titles On-Line database. Map is in UTM
Projection, Zone 10, NAD 83.
The Akie claims are on Crown land, and the area is open to mineral exploration and
development. Requirements under the Mineral Tenure Act are that work be performed to a per
hectare value of $4 for the first three years of a tenure and $8 per hectare in the fourth and
subsequent years. Previous exploration expenditures have been filed for assessment credit with
the B.C. Ministry of Energy and Mines. Table 1 reflects the current expiry dates of the claims
based on assessment credits applied to date. As of April 30, 2008, all mineral tenures held by
Ecstall and Mantle have a good-to-date of December 20, 2017.
As with all mineral tenures in British Columbia, a prerequisite to the issuance of a work permit
by the Ministry of Energy, Mines and Petroleum Resource, is that Mantle consult with local
First Nations who may have an interest in the area. It is the writers understanding that this has
been done and that local First Nations are aware of the work being done on the property.
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A claim map of the Akie property is shown in Figure 3. Also shown are the locations of drill
hole collars, grid lines, original Cardiac Creek showing and approximate surface trace of the
known mineralized zone.
5.0 ACCESSIBILITY, CLIMATE, LOCAL RESOURCES,
INFRASTRUCTURE AND PHYSIOGRAPHY
The Akie property, which is located approximately 280 kilometres northwest of Mackenzie
B.C, is currently only accessible via helicopter. However new logging roads in the Akie River
valley are within a few kilometers of the property providing nearby road-accessible camping
and equipment staging areas. Airstrips and nearby logging camps are located further to the east
in a broad, north trending valley known as the Northern Rocky Mountain Trench. Access to
these camps is via a network of Forest Service Roads that connect to the town of Mackenzie, a
major industrial centre with several lumber and paper mills.
The Akie River area is mountainous with a series of northwest trending ridges, locally rising to
2,200 metres elevation, transected by broad northeast trending drainage corridors. The northeast
facing ridge slopes are generally steep and have excellent exposure; the southwest facing slopes
dip moderately and are generally covered with talus, moss and grass. The climate is cool with
moderate rain and snow fall. Most valleys are free of snow by mid June.
Although snow is not unusual at higher elevations even during the summer months, it does not
begin to accumulate until late September. Temperatures in the summer months range from 5 to
30 degrees Celsius with an average near 18 degrees Celsius.
Vegetation in the area is restricted to valleys and lower slopes which are heavily timbered with
spruce and other subordinate species. Extensive swamps occur in the broad valley bottoms that
are associated with major drainage corridors. Landslide and avalanche scars are common on
steeper slopes. Locally, vegetation has been killed by high concentrations of barite float in talus
slopes. Iron oxide has been precipitated where springs drain iron rich black shales; springs
draining carbonate rocks precipitate calcium carbonate. Locally a lime-green "zinc moss"
occurs where springs drain zinc rich shales.
Above the tree line, the environment is sub-alpine, with mosses and lichens predominating.
Alpine flowers are also abundant in the summer months. Animal species include abundant
grizzly bear, cariboo, mountain goats and marmots.
6.0 HISTORY
6.1 Gataga District
Recognition of the potential for clastic-hosted stratiform sulphide and barite deposits of the
Meggen and Rammelsberg type in Paleozoic basinal facies rocks of the North American
miogeocline resulted in regional geological and geochemical exploration programs particularly
within the Selwyn Basin of Yukon. This work resulted in discovery of the Howard's Pass
deposit in 1972 and the Jason deposit in 1975. In the late 1970’s the focus of exploration
activity shifted southward toward the relatively unexplored Kechika Trough of the Northern
Rocky Mountains.
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Figure 4. Generalized geology of the Gataga mineral district showing location of major
prospects.
Geophoto Consultants first explored the northern part of the Kechika Trough in 1970. In 1972,
Canex Exploration (Placer Development Ltd.), while following up this earlier work, discovered
bedded barite-sulphide occurrences in Devonian black clastics near Driftpile Creek (Figure 4).
However, the most significant discovery known to date was not made until 1977 when a Cyprus
Anvil/Hudson's Bay Oil and Gas Ltd. joint venture discovered the stratiform Cirque deposit in
similar strata further to the south in the Paul River area (Figure 4). This deposit has an historical
resource estimate in excess of 40 million tonnes containing 7.8 per cent zinc, 2.2 percent lead,
and 48 grams per tonne silver. Extensive drilling at the Cirque and South Cirque deposits has
provided much valuable information on the stratigraphic and structural settings of the stratiform
barite-sulphide deposits.
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When the Cirque deposit was acquired by Curragh Resources in 1985 it was subsequently
renamed the Stronsay deposit. In 1989 Austriana de Zinc purchased 15% of the deposit from
Curragh. The $10 million received from this sale was used to finance underground exploration,
additional diamond drilling, metallurgical testing and environmental studies between 1989 and
1991. Total expenditure on the property to the end of 1991 was $55 million (1990 dollars). In
1994, Curragh Resources went into receivership. The Cirque property was subsequently
acquired from the receiver by Teck Corporation (25%), Cominco Limited (25%) and Korea
Zinc Company (50%). After completing a feasibility study in 1995, the new owners decided to
defer a production decision until the zinc market improves.
Diamond drilling has also been done at the Pie, Fluke, and Elf prospects, all of which have
bedded barite and massive sulphide hosted by Late Devonian black clastics of the Earn Group
(Figure 4). Middle Devonian and Mississippian age barite deposits have also been discovered in
the area and these appear to be spatially associated with the Late Devonian occurrences
suggesting a common structural control.
In 1980, Cominco Ltd. discovered the Aikie-Sika, ERN, CT stratiform barite-sulphide
occurrences in Early Silurian clastic and carbonate strata that stratigraphically and lithologically
resemble those hosting the Howard's pass deposit of Selwyn Basin. Also in 1982, ESSO located
a stratiform massive pyrite body in probable Middle Ordovician black shales (Reb prospect).
These discoveries further enhanced the overall potential of the district and prove the existence
of more than one mineralizing event in the depositional history of the Kechika Trough.
The most recent discovery in the project area was made by Metall Mining Corporation in 1994
while exploring ground optioned from Ecstall Mining Corporation. This discovery, now known
as the Akie (Cardiac Creek) deposit (no 23, Figure 4) and is the subject of this report.
6.2 Akie Property
The Akie claims were originally staked in 1978 by Rio Canex as part of the Dog claim group to
cover an area of anomalous lead in stream sediment silt samples. Between 1979 to 1981
geological, soil geochemical and VLF surveys were completed. According to Baxter (1996) this
work defined several zones of anomalous Pb, Zn, Ag and Ba in soils were outlined in areas
underlain by Middle to Upper Devonian Gunsteel Formation cherty argillites and shales.
However, Rio Canex did little or no follow-up exploration in the area of these anomalies
although mapping and prospecting did locate two zones of nodular barite on the ridge adjacent
to the Fluke claims. Discouraged by the lack of base metal sulphides Rio Canex allowed the
claims to lapse in 1985.
In 1989 Ecstall Mining Corporation staked the Akie 1, 2 and 3 claims adjacent to the southern
edge of the Fluke claims and in 1992 optioned the claims to Inmet Mining Corporation
(formerly Metall Mining). In 1992 and 1993, Inmet re-gridded Fluke ridge and defined an 800
metre Pb-Ag soil anomaly with local barium highs. Lithogeochemical sampling on
reconnaissance traverses southeast of the then claim boundary also showed that the Gunsteel
formation in this area contained anomalous concentrations of Pb, Zn and Ag. The 1992 and
1993 Inmet exploration programs are summarized by G.S. Wells in assessment and company
reports.
In early 1994, compilation of open ground previously held by Rio Canex between the Akie 1-3
claims and the Elf property indicated the 1992-1993 Inmet Pb-Ag soil anomaly extended for
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another five kilometers along strike within the Gunsteel formation with RioCanex soil values of
up to 4100 ppm Pb, 9500 ppm Zn, 11,000 ppm Ba and 25 ppm Ag (Baxter, 1996). In April of
1994, the Akie 4-7 claims were staked to cover this area. In June of 1994, 24.4 kilometres of
line cutting and soil sampling redefined many of the previous soil anomalies. In July of 1994,
prospecting along the trend of the soil anomalies lead to the discovery of narrow high grade
massive sulfides in Cardiac Creek (16.0% Zn, 2.8% Pb over 40 centimetres). Following this
discovery, the Akie 8-17 claims were staked, the soil grid was further extended to the southeast
and the grid was covered by a 20.1 kilometre VLF Resistivity-Magnetics survey.
In 1994, the new massive sulfide discovery was drill tested by 12 diamond drill holes (A-94-1
to A-94-12) totaling 3753.2 metres. This work defined a 1400m long mineralized sheet tested to
depths of 300m below surface. Drill hole A-94-12 intersected 30.5 metres (true thickness)
grading 4.2 per cent zinc, 0.9 per cent lead and 9.7 grams per tonne silver. Included in this
intersection are 7 metres grading 8.4 per cent zinc, 1.6 per cent lead and 14.3 grams per tonne
silver (Baxter).
In 1995, Inmet Mining Corporation drilled an additional seven holes (A-95-13 to A-95-19)
totaling 4949.7 metres to depths in excess of 1000 metres, testing the down dip extent of the
deposit. Additional soil and rock geochemistry was also done on the property.
In 1996, Inmet continued deep drilling along the Cardiac horizon, as well as "reconnaissance"
drilling of soil and geophysical anomalies along strike from known mineralization. The drilling
program involved completion of hole A-95-19 and 10 new holes, A-96-20 to A96-29 for a total
of 4982.6 metres of diamond drilling. By the end of the 1996 program the Cardiac Creek zone
had been traced by drilling along a strike length of 1400 metres, with a true thickness ranging
from 10 to 30 metres, and extending to depths of 600 metres. Based on the results of drilling,
Inmet estimated a pre NI43-101 geological resource of 12 million tonnes grading 8.6 per cent
zinc, 1.5 per cent lead and 17.1 grams per tonne silver (MINFILE database). Surface drilling
also tested the strike projection to the north and south of the Cardiac zone at 1 kilometre
intervals over a distance of approximately 7 kilometres. Encouraging results were reported,
particularly from the northern end of the property.
In the period 1994 to 1996, a total of $3,798,173.43 was filed for assessment credit as
documented in assessment reports 23870, 24439, 24323 and 24703 (Baxter, 1995, 1996, 1996a,
1996b). Most of this cost was related to completion of 13,685.5 metres of diamond drilling in
29 drill holes (MacIntyre, 2005)
In July of 2005, Mantle Resources Inc. optioned the Akie property from Ecstall Mining
Corporation and contracted Coast Mountain Geological Ltd. to manage a short, four-hole drill
program on the property during the late fall of 2005, for as long as weather would permit. The
program redefined the Cardiac Creek unit, a shale unit within the Upper Devonian Gunsteel
formation which hosts a sedimentary exhalative (SEDEX) style zone of massive zinc-leadsilver (Zn-Pb-Ag) mineralization.
A total of 1,999.1 m of diamond drilling was completed in 2005 in 4 holes (Vanwermeskerken
and Metcalfe, 2006). Three holes successfully intersected mineralization, and one hole (A-0531) was abandoned when the drill stem was pinched by a fault. The last hole (A-05-33) was
abandoned when extreme cold froze the waterlines at both the drill and in camp. Although the
drill had already intersected and passed through the target mineralized horizon, it was still
returning brecciated and mineralized sections with as much as 60% pyrite.
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Each hole completed intersected massive sphalerite-pyrite-galena. Assays returned for drill hole
A-05-30 averaged 11.87% Zn, 2.83% Pb and 23 gm/t Ag over 34.05 m, including 17.93 m of
17.22% Zn, 4.20% Pb and 30 gm/t Ag. Drill hole A-05-32 returned values of 10.28% Zn,
2.16% Pb and 21 gm/t Ag over 36.40 m, including 8.20 m of 18.50% Zn, 3.97% Pb and 30 gm/t
Ag.
Drill hole A-05-33 returned values averaging 7.85% Zn, 1.61% Pb and 14 gm/t Ag over 22.60
m, including 9.81% Zn, 2.20% Pb and 19 gm/t Ag over 11.50 m. The drill hole had already
pierced the projected mineralized zone, but was still in pyrite-rich breccia when frozen
waterlines precluded continuation of drilling. The nearby hole A-95-18 intersected two
‘stacked’ mineralized zones, separated by a fault; a similar fault repetition may exist beyond the
end of hole A-05-33.
Drillhole deviation was very strong, with as much as a 13° azimuth deviation over 60 m and a
5° dip deviation over 24 m in A-05-30. In general, the deviation was a refraction of the drill
hole into the bedding-parallel cleavage of the black shales. However, a less predictable
variation was possible when a hole intersected a major fault.
The results indicated high levels of lead and zinc over significant widths much greater than the
historical results. As a result Mantle Resources under the management of Coast Mountain
Geological Ltd. initiated a larger drilling program on the property in the spring of 2006.
The program began mid May 2006 and planned for the drilling of 12 targets surrounding the
three successful 2005 holes with a rough 100m spacing designed to pierce the Cardiac Creek
Unit. This plan was changed shortly into the drill program with the targets being moved into a
drill fan orientation located 50m up dip and 75m and 150m down dip of the 2005 holes. The
remainder of the drilling program focused on attempting to hit these redefined targets as best as
possible given problems with hole deviations.
During the 2006 exploration season 11 drill holes were started, with 7 being completed and
piercing the Cardiac Creek unit for a total of 4,880.58 meters being drilled (Johnson and
Metcalfe, 2007). All seven of the completed holes pierced the Cardiac Creek unit however drill
hole deviation proved to be a significant problem and resulted in limited success in achieving
the intended targets with the actual pierce point being out by an average of 35m (with respect to
the vertical long section) with a couple being off by noticeably more at 78m and 153m.
Even with the hole deviation the results in 2006 were considered very successful with hole A06-35 returning 8.91% Zn, 1.80% Pb over 21.90m, A-06-37A returning 8.35% Zn, 1.73% Pb
over 25.60m, A-06-38 returning 7.78% Zn, 1.35% Pb over 24.05m and hole A-06-39A
returning 8.07% Zn, 1.62% Pb over 18.10m. (Johnson and Metcalfe, 2007). The 2006 drill
program was terminated in late October due to frozen waterlines.
Encouraged by the results of the 2005 and 2006 drilling programs, Mantle completed an
additional 6,526 metres of drilling in 12 holes (A-07-42 to A-07-53) in 2007. Best results were
from drill holes A-07-42 returning 13.83% Zn, 3.24% Pb over 11.32m, A-07-43 returning
15.64% Zn, 4.29% Pb over 11.89m, A-07-45 returning 18.42% Zn, 4.17% Pb over 16.4m, A07-49 returning 14.47% Zn, 3.23% Pb over 7.61m and A-07-50 returning 16.67% Zn, 3.41% Pb
over 20.98m.
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Figure 5. Geology of the Akie River area (after MacIntyre, 1998)
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Figure 6. Stratigraphic column, Akie River district (after MacIntyre, 1998)
7.0 GEOLOGICAL SETTING
In northeast British Columbia, Paleozoic miogeoclinal basinal facies rocks of ancestral North
American affinity were deposited in the Kechika Trough, a southeast extension of the Selwyn
Basin.
The Kechika Trough is bounded to the west and east by carbonates and shallow water clastic
rocks of the Cassiar and MacDonald Platforms respectively (Taylor and MacKenzie, 1970).
Rocks of the MacDonald Platform are host to Mississippi valley type Pb-Zn deposits
(MacQueen and Thompson, 1978).
The Akie River area is located within the Rocky Mountain fold and thrust belt of northeast
British Columbia. Within this tectonic belt, northeast-directed contraction in Mesozoic time
detached Paleozoic and older sedimentary strata from the cratonic basement and stacked these
rocks as a series of southwest-dipping imbricated thrust plates (McClay et al., 1989; Price,
1986).
The Kechika Trough is truncated by a major transcurrent fault that is coincident with the
Northern Rocky Mountain Trench (Gabrielse, 1984). Reconstruction of the geology on either
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side of the trench suggests rocks west of the trench were displaced 450 or more kilometres
northward (Tempelman-Kluit, 1977) by movement along dextral strike-slip faults in Mesozoic
and Cenozoic time.
The Akie River area is underlain by a thick succession of basinal facies clastic and subordinate
carbonate rocks of Late Cambrian to Late Triassic age. These rocks crop out in narrow
northwest-trending panels bounded by southwest-dipping thrust faults. The thrust panels are
internally deformed into a series of tight, parallel, generally northeast-verging asymmetric,
upright to overturned folds.
Although the map pattern reflects the effects of thrusting and folding, the geomorphology
reflects the effects of differential erosion. The more resistant formations are usually well
exposed, especially where they have been thrust up to form the backbones of prominent ranges.
Recessive formations, on the other hand, are usually poorly exposed and typically underlie low
hills and valley bottoms. This is particularly true of the Devonian shales that host the important
stratiform barite-sulphide deposits of the district. Also, because of the relatively high
stratigraphic position of these Devonian rocks, they usually occur only in the deeper synclinal
troughs that lie below major thrust faults; elsewhere they are largely removed by erosion.
Recognition of these factors is critical to successful exploration and resource assessment of the
area.
7.1 Lithostratigraphic Units
In the Akie River area, as is typical of turbiditic sequences near basin margins in general, facies
changes are numerous and reflect the effects of changing water depth, paleoslope orientation
and tectonic activity during the course of basin evolution. The Paleozoic stratigraphic
succession records the history of several marine transgressive cycles. Each cycle begins with
shallow water carbonate and associated clastic sedimentation and ends with deposition of deep
water black shale. These fining upward marine transgressive cycles are Late Cambrian to Early
Ordovician, Mid-Late Ordovician, Early Silurian, Early Devonian and Late Devonian to Early
Mississippian in age.
7.1.1 Proterozoic to Early Cambrian - Windermere Supergroup
Sedimentary rocks of Proterozoic age are exposed in major thrust plates and anticlinoriums east
and north of the Gataga district (Figure 5). These rocks correlate with the Windermere
Supergroup, a prograding clastic wedge that was deposited along the continental margin of
ancestral North America in Late Proterozoic time. Coarse grit units within this sequence may
have acted as important aquifers in the formation of both sediment and carbonate hosted zinclead-silver deposits (Lydon et al., 1986).
7.1.2 Early to Late Cambrian - Gog Group
In the northern half of the Gataga District, Early to Late Cambrian quartzite and massive
limestone are exposed in a series of northwest-trending thrust plates (Fritz, 1979). These rocks
are part of a chain of carbonate buildups that extends southward toward the Akie River area
(Figure 5). These carbonate buildups were bounded by inner shelf and outer shelf clastic facies
rocks to the east and west respectively. Fritz (1979) suggests these rocks are correlative with the
Gog Group of the southern Rocky Mountains.
Rocks of Early to Late Cambrian age do not crop out in the Akie River area but are exposed in a
chain of prominent limestone peaks immediately to the west. The Cambrian carbonate and
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quartzite units are believed to underlie the Akie River area and may comprised a relatively
ridgid basement upon which Paleozoic strata have been detached and thickened by northeast
directed thrusting.
7.1.3 Cambrian to Ordovician - Kechika Group
In the southern part of the Gataga district, the Cambrian limestone is overlain by up to 1,500
metres of cream to light grey-weathering, talcy, nodular phyllitic mudstone and wavy banded
limestone of the Kechika 'Formation' (Cecile and Norford, 1979). The nodular structures in
these rocks are the result of stretching and attenuation of sandy beds within a plastically
deformed muddy matrix. Intense stretching and development of penetrative foliation within
Kechika rocks relative to overlying and underlying successions may be the result of detachment
and sliding of thrust plates along this unit. Much of this deformation is believed to be related to
uplift of the Rocky Mountains in Tertiary time with northeast directed compression producing a
series of stacked thrust plates. Kechika rocks, which range in age from latest Cambrian to late
Early Ordovician, are well-exposed at the base of several large thrust plates. Lithologically
similar rocks are absent or very thin in the northern part of the district, where, Ordovician shales
directly overlie Cambrian limestone and quartzite (MacIntyre, 1983).
Several thin beds of greenish weathering tuff were noted in the sections of nodular phyllitic
mudstone, particularly north of the Akie River. These tuff beds, which are rarely more than one
metre in thickness, are evidence for volcanic activity during the late Cambrian to early
Ordovician time period.
7.1.4 Early to Late Ordovician - Skoki limestone
The thickest sections of Ordovician limestone occur in the Pesika Creek area and northeast of
the Kwadacha River. Here, sections up to 500 metres thick of thin-bedded limestone occupy the
same stratigraphic position as much thinner sections of limy siltstones and limestone debris
flows elsewhere in the district. Both Jackson et al. (1965) and Davies (1966) concluded these
limestones lie below the Paraglossograptus etheridgei graptolite zone, which is earliest Middle
Ordovician. Lithologically similar rocks are very thin or absent in the northern part of the
Gataga district where graptolitic shales and platy siltstones directly overlie Cambrian limestone.
7.1.5 Ordovician to Early Devonian - Road River Group
In the southern part of the district, Kechika rocks are unconformably overlain by a succession of
calcareous siltstone, shale, limestone, and volcanic rocks which have previously been assigned
to the Road River Formation (Taylor et al., 1979; Cecile and Norford, 1979). MacIntyre (1998)
assigned all rocks overlying the Cambrian to Ordovician Kechika Group and underlying the
Middle to Late Devonian Earn Group (black clastics) to the Road River Group following the
informal usage of Gordey et al. (1981). Road River rocks reflect the establishment of an abrupt,
well defined basin-platform transition zone along the eastern margin of the Kechika Trough that
persisted from Early Ordovician to Late Devonian time (Cecile and Norford, 1979). Clastic
sediments were apparently deposited in the trough by turbidity currents moving down relatively
steep westward-dipping paleoslopes.
The stratigraphy of the Road River Group in the Ware map-area (94F) has been described by
Cecile and Norford (1979). In the Akie River area, the Ordovician part of the group includes a
lower unit of cream, beige, and reddish brown-weathering, laminated calcareous siltstone and
shale with intercalated limestone turbidites and debris flows. Cecile and Norford (1979)
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suggested that the latter are derived from the platformal Skoki limestone which crops out along
the eastern and southern margins of the district.
Thin-bedded calcareous siltstones of the lower Road River Group grade up section into a
distinctive unit of black shale that contains abundant Middle to Late Ordovician graptolite
fauna. These fauna are part of the Caradoc and/or Ashgill series of the late Middle and early
Late Ordovician. Graptolites are a very useful tool for distinguishing Ordovician black shales
from lithologically identical Devonian rocks. The Devonian graptolite faunas are sufficiently
distinctive from the Silurian and Ordovician fauna to allow identification in the field.
Black chert horizons are locally interbedded with the shales particularly in the vicinity of the
REB massive pyrite lense. The black shales onlap platformal carbonates to the south and east
and are evidence of a major marine transgression that took place in Mid to Late Ordovician
time. The base of the black shale unit is probably diachronous, younging eastward.
Gabrielse (1981) has suggested that the black shale unit has been removed by pre-Silurian
erosion in the area southwest of the Gataga district because Kechika or basal Road River rocks
there are directly overlain by Silurian siltstone. This data suggests that a shallow water shelf or
platform was located along the west side of the Kechika Trough, and sediments in it were
periodically exposed and eroded during marine regressions prior to early Silurian time.
Along the eastern edge of the Kechika Trough, graded and cross-laminated beds of quartz
wacke, arenite and pebble conglomerate occur locally within the black shale unit. These
quartzose tubidites which vary considerably in thickness and grain size, appear to have been
deposited as submarine fans along the western margin of the MacDonald Platform. The quartz
detritus may have been derived by erosion of Cambrian or older quartzites that were exposed
east of the platform in Mid Ordovician time. Black shales interbedded and overlying the quartz
wacke beds contain late Middle to Late Ordovician graptolite assemblages.
7.1.6 Ospika Volcanics
In the Akie River area, a northwest-trending belt of mid Ordovician volcanics extends from the
Paul River to the Ospika River and beyond. The volcanics occur as discontinuous lenses and
beds of green mafic flows or microdioritic sills and orange-weathering ankeritic crystal and
lapilli tuffs. They are interbedded with both the late Early to early Middle Ordovician black
shale facies and time equivalent platformal carbonates. The areal extent of Middle Ordovician
submarine volcanic rocks parallels the central axis of the Kechika Trough. The composition and
linear distribution of these rocks suggests they were erupted along rifts bounding the
sedimentary troughs.
7.1.7 Silurian Siltstone
Orodovician black shales are overlain by Early to Middle Silurian marine sedimentary rocks
that are also included in the Road River Group. The basal part of the Silurian section, which
ranges from 0 to 20 metres thick, consists mainly of thin-bedded to cross-laminated limestone
and dolostone beds. Interbedded with these rocks and overlying black chert, laminated grey
calcarenite and dark grey dolomitic shale are 1 to 2 metre thick limestone and dolostone debris
flows. Orange-grey weathering quartz wacke and quartz arenite beds also occur within this unit
and typically overlie or are interfingered with the basal limestone beds. These quartz-rich beds
are only found along the eastern margin of the trough and appear to thicken eastward toward the
MacDonald platform. By contrast, limestone and dolostone beds predominate within the trough.
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The basal Silurian limestone unit is overlain by tan to orange-brown weathering dolomitic
siltstone with varying proportions of orange-weathering limestone and dolostone interbeds. This
unit varies from 100 to 500 metres in thickness. Immediately above the basal limestone
member, the siltstone is thin-bedded, platy to shaly and recessive; it becomes thicker, more
flaser-bedded, and resistant up section. The thick-bedded dolomitic siltstones are strongly
bioturbated with numerous worm burrows and feeding trails exposed on bedding planes. Poorly
preserved graptolites and sponge impressions are found in platy-weathering siltstone and shale
members. Cecile and Norford (1979) documented an unconformable relationship between the
dolomitic siltstone and basal limestone units. The Silurian rocks are separated from underlying
Ordovician graptolitic black shales by a sub-Middle Llandovery unconformity (Cecile and
Norford, 1979). The basal limestone and overlying cherts and shales were deposited during a
short-lived marine transgression that preceded a major regression and infilling of the Kechika
Trough with dolomitic detritus derived from the MacDonald platform.
The Silurian siltstone unit is relatively uniform throughout the Kechika trough. In general, it is a
dolomitic siltstone with such shallow water features as flaser bedding, worm burrows and
feeding trails. These features, plus the fact that the unit is bounded by major unconformities,
even within the deepest parts of the trough, suggests that a major marine regression occurred in
Middle Silurian time. this led to extensive erosion of the carbonate platform and partial infilling
of the Kechika Trough with reworked dolomitic detritus.
In the Gataga district, Silurian siltstones are disconformably overlain by clastic and carbonate
rocks of Devonian age. All of these rocks are included in the Road River Group.
In the Akie River district, the Silurian siltstone unit is overlain by marine turbidites that are in
whole or in part Lower Devonian in age (MacIntyre, 1998). This unit, informal known as the
Paul River formation (Pigage, 1986), includes black chert, interbedded black shale and
limestone debris flows, rusty weathering dark grey siltstone to silty shale and, in the eastern part
of the district near the platform margin, quartz wacke. All of these rocks are mapped as part of
the Road River Group (MacIntyre, 1998).
The transition from Silurian siltstone to overlying, deeper water turbidites is often marked by a
thin unit of platy weathering black chert, cream to tan weathering dolomitic mudstone or
siltstone and limestone. Irwin (1990) reports the occurrence of Lochkovian (Early Devonian)
conodonts in this unit. In turn, this member is overlain by interbedded dark grey calcareous
siltstone and laminated black silty shale that contains Early Devonian graptolites (MacIntyre,
1998). The cherty argillites and laminated mudstones appear to be restricted to the deeper water
parts of the Devonian succession and may be distal equivalents of coarser grained Early
Devonian slope facies rocks mapped as part of the Road River Group.
Along the eastern basin to platform transition zone, a resistant unit of grey, thick bedded quartz
sandstone and siltstone turbidites up to 200 metres thick, occurs near the base of the Devonian
succession (MacIntyre, 1998). This member is stratigraphically overlain by interbedded
limestone debris flows and black shales. The latter contain Lower Devonian graptolites. The
best exposures of quartzose turbidites occur in the North Kwadacha River area, particularly near
the crest of Fern Peak.
A distinctive unit of interbedded limestone debris flows and graptolitic black shales overlies the
basal quartz sandstone-siltstone unit or sits directly on Silurian siltstone. Clasts within the
debris flows are subangular to subrounded, 2 to 30 centimetres in diameter, and moderately to
well-sorted and graded. Clast size decreases basinward and presumably downslope from the
source area. Dr. Brian Norford of the Geological Survey of Canada identified the Pragian age
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(Early Devonian) graptolite Monograptus yukonensis in samples of shale collected from this
part of the Devonian section (MacIntyre, 1998). The limestone turbidites are restricted to two
linear belts separated by the shallow water carbonate buildups of the northwest-trending Early
to Middle Devonian Kwadacha, Akie and Pesika Reefs. The Early Devonian section is also
present as far south as the Ospika river and along the basin to platform transition zone on the
east side of the study area. These rocks apparently thin and fine up section and basinward and
are interpreted to be slope facies turbidites.
In the Akie River area, a unit consisting of dark grey to brown weathering, recessive, silty shale
and siltstone overlies Early Devonian limestone turbidites and shales. In part, these rocks onlap
the Early to Middle Devonian carbonate buildups of the Akie and Kwadacha reefs. Bands and
laminae of silt and sand characterize this unit. Some of the silty bands are calcareous and
weather to an orange to brown colour. This unit appears to be thickest along the western
margins of the Akie and Kwadacha reefs; it rapidly thins and fines basinward. This unit is very
thin or absent in the thrust panel containing the Cirque deposit. Pigage (1986) and Jefferson et
al., (1982) included these rocks with the black shales of the Akie formation. MacIntyre (1998)
assigned these rocks to the Paul River formation of the Road River Group; the Akie formation
was restricted to silty shales of Late Devonian to Mississippian age.
Five to ten centimetre thick beds of orange to green weathering crystal tuff occur sporadically
within the Early to Middle Devonian section. These tuff beds increase in thickness and number
toward the southwest corner of the map area.
7.1.8 Early to Middle Devonian - carbonate reefs
Thick carbonate buildups of the Akie, Kwadacha and Pesika Reefs, which apparently range in
age from late Early to late Middle Devonian (Gabrielse, 1975), disconformably overlie the
Silurian siltstone unit. Early Devonian limestone turbidites and shales are absent below the
thickest parts of the reefs, suggesting that these areas were topographic highs where the Early
Devonian strata were either eroded away or never deposited. Beneath the reefs, the upper part
of the Silurian section is often red to pink-weathering, suggesting possible exposure and
oxidation prior to the main episode of marine transgression and carbonate deposition
(MacIntyre, 1998).
The Akie and Kwadacha Reefs are up to 200 metres thick along their western margins and
apparently thin gradually to the north and east. The reefs are mainly composed of medium to
thick-bedded micritic and bioclastic limestone with occasional thin bedded shaly and
argillaceous intervals. Locally, the reefs are very fossiliferous with crinoid, coral and
stromatoporoid-rich zones. Beds rich in 'two hole' crinoid ossicles typically occur near the tops
of the reefs. The presence of crinoid ossicles with twin axial canals indicates a probable late
Early to early Middle Devonian age (MacIntyre, 1998).
In the Pesika Creek area, thick-bedded reef limestones overlie Early Devonian graptolitic shales
and limestone debris flows of Early Devonian age. This stratigraphic relationship suggests that
reef growth and carbonate buildup advanced basinward during Middle Devonian time.
Gabrielse (1981) described pebble conglomerates directly overlying Middle Devonian
limestone of the Akie Reef near its eastern limit. These coarse clastic rocks were probably
deposited along a shoreline bounding a northwest-trending landmass that was exposed during
this time period. This unconformity does not appear to extend into adjacent troughs where
clastic sedimentation appears to have been continuous for most of the Devonian.
- 26 -
7.1.9 Middle Devonian to Mississippian - Earn Group
Blue grey weathering shale, siliceous carbonaceous shale, cherty argillite, porcellanite and
coarse quartzose turbidites ranging from Middle Devonian to Mississippian in age overlie rocks
of the Road River group. These rocks are similar in age and lithology to the Earn Group as
defined by Campbell (1967) and as used by Gordey et al.,(1981) in Selwyn Basin. MacIntyre
(1998), following the usage of other workers in the area (Pigage, 1986), divided the Earn Group
into three informal formations - the Gunsteel, Akie, and Warneford.
The Earn Group was deposited during a major marine transgression that terminated reef growth
and resulted in progressive onlapping of fine clastic sediments onto the MacDonald platform.
These relationships suggest that the base of the Earn Group is diachronous, younging
progressively to the east.
Gunsteel formation
In the Akie River district, a distinctive unit of bluish grey-weathering, rhythmically bedded
cherty argillite and siliceous carbonaceous shale, that is informally called the Gunsteel
formation, overlies Early to Middle Devonian siltstone and silty shale (MacIntyre, 1998). The
Gunsteel rocks also onlap and, in part, are interbedded with the Early to Middle Devonian
carbonate buildups of the Akie, Kwadacha and Pesika Reefs. The Gunsteel formation is of
similar lithology and age to rocks assigned to the lower Earn Group by Gordey et al. (1981) in
the Selwyn Basin. These Earn Group rocks are of particular importance; they host major
stratiform barite-sulphide deposits both in the Selwyn Basin and in the Kechika Trough.
The siliceous Gunsteel rocks vary from less than 20 metres thick near the margins of the shale
basin, where they onlap reef limestones, to several hundred metres thick in adjacent troughs.
They are resistant and typically blocky to slabby-weathering. The unit is comprised of medium
to thin beds of banded black chert or porcellanite, cherty argillite, laminated siliceous silty
shale, black siltstone, and black carbonaceous shale.
Thin beds of grey siltstone, dark grey fetid limestone and bioclastic limestone debris flows that
contain clasts with two hole crinoid ossicles occur locally, particularly near the interbasin reefs.
These debris flows are probably derived from crinoid-rich beds that occur near the tops of the
reefs, suggesting that Gunsteel rocks are, in part, basinal correlatives of the reefs. Orchard of
the Geological Survey of Canada has identified late Middle to earliest Late Devonian (late
Givetian-early Frasnian) conodont fauna both in crinoidal limestone beds within the Gunsteel
section and from crinoid rich beds within the reefs, further supporting this correlation
(MacIntyre, 1998).
Barite beds stratigraphically below the Cirque deposit contain the ammonoid Ponticeras
(Jefferson et al., 1983), an index fossil for the earliest Late Devonian (Frasnian). A limestone
bed in the footwall sequence of the Kwadacha barite deposit contained a conodont fauna of
similar age (MacIntyre, 1998). These data provide further evidence for a late Mid to early Late
Devonian age range for Gunsteel rocks and their contained barite-sulphide deposits.
Soft sediment slump structures are common in Gunsteel rocks and intraformational breccias
occur locally. These deposits suggest growth faults may have been active during deposition of
the Gunsteel rocks.
Laminae of pyrite and nodular barite are typically present in black cherty mudstone beds near
the top of the Gunsteel formation. These beds are present regionally and are at the the same
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stratigraphic position as barite-sulphide deposits in the district. They are a useful tool for
delineating favourable stratigraphy for barite-sulphide deposits.
Akie Formation
Gunsteel rocks are conformably overlain by recessive, thick bedded, non-siliceous, rusty brown
to tan weathering, medium grey aluminous shales of probable Late Devonian to Mississippian
age. These rocks comprise the informal Akie formation as first defined by Jefferson et al.,
(1983). The Akie formation correlates, in part, with the Besa River formation (Pelzer, 1966) of
the MacDonald Platform. These formations were deposited during a major, eastward advancing,
marine transgression that occurred in Late Devonian to Mississippian time.
The Akie formation shales are difficult to distinguish from older shale members in the district.
However, in general they have a phyllitic sheen on cleavage surfaces and show faint colour
banding, which is less common in other shale members. Orange weathering calcarenite beds,
although rare, are also locally present. The basal part of the Akie formation is typically rusty
weathering and may contain pyrite laminae and barite nodules.
Warneford Formation
Proximal to medial turbidites, characterized by grey-weathering resistant beds of chert pebble
conglomerate, quartz wacke and siltstone, interfinger with Late Devonian to Mississippian
black shales of the Akie formation in the Warneford River area, northwest of the study area.
These quartzose turbidites are informally called the Warneford formation. This formation is thin
or absent is the current study area. However, thin quartzose siltstone and wacke beds that occur
in the Gunsteel section that hosts the Cirque deposit may be distal equivalents of the Warneford
formation (Pigage, 1986).
In the Driftpile Creek area, the Warneford formation turbidites are part of a series of submarine
fan deposits that thicken and coarsen westward (Carne,1978). This suggests that an actively
eroding landmass existed along the western margin of the Kechika trough in Late Devonian to
Mississippian time. Gordey (1981) suggested that an extensional or trans-tensional regime was
responsible for source area elevation and basin development in the Selwyn Basin at this time
and a similar conclusion appears valid for the Kechika Trough.
7.1.10 Mississippian to Triassic - chert and siltstone
The youngest rocks in the Gataga district are the dolomitic siltstones and limestones that occur
in the core of a large, northwest-trending synclinorium located northeast of the Kwadacha
River. Although these rocks are lithologically similar to the Silurian siltstone unit, they are
easily distinguished by the presence of Triassic brachiopods (Gabrielse, 1977).
The Late Triassic rocks are separated from underlying Devono-Mississippian strata by a 10 to
20-metre-thick layer of light coloured, chalcedonic chert that may correlate with either the
Mississippian Prophet Formation or the Permian Fantasque Formation that occur in the
MacDonald Platform, east of the Kechika Trough.
7.2 Structure
The linear nature of the geology of the Akie River area reflects the "thin-skinned" tectonic style
of the Rocky Mountain Fold and Thrust Belt. Northeast-directed compression resulted in
detachment of the Paleozoic strata from a rigid crystalline basement and partial stacking of the
detached plates along a series of imbricate thrust faults. The thrust plates, which are composed
- 28 -
of relatively incompetent basinal facies rocks, have been internally folded during thrusting. In
general, incompetent strata below overriding thrust plates have tight isoclinal folds with
southwest-dipping axial planes whereas rocks in the overriding plate are asymmetrically folded
and often have northeast-dipping axial planes. This style of folding may be related to the
development of inversion structures similar to those described by McClay et al., (1989) in the
Driftpile Creek area.
The structural style changes from west to east across the map area. In the west, imbricate,
southwest dipping reverse faults bound asymmetric overturned folds with southwest dipping to
vertical axial planes. To the east, large scale upright folds occur within major synclinoriums that
are bounded by outward dipping reverse faults that truncate folds within overriding
anticlinoriums. Devonian strata are preserved within the synclinoriums. This structural style
suggests that high angle growth faults bounding depositional troughs in Devono-Mississippian
time were reactivated during Tertiary compression and became the locus of major thrust faults
in the district. That major high angle thrust faults may be localized along much older crustal
breaks is also suggested by close spatial association of Paleozoic mineralization, reef building,
coarse clastic fans and volcanism to such faults.
Detailed studies of the structure of the Cirque deposit led to the recognition of two coaxial
phases of deformation (Pigage, 1986). The earliest deformation, which is recognizable
throughout the study area, includes northwest-trending, tight asymmetric folds that verge
northeast and have gently dipping southwest limbs and steep to overturned northeast limbs. The
steep limbs are often broken and offset by high angle reverse faults, resulting in the
juxtaposition of Ordovician and Silurian strata against the Mid to Late Devonian Gunsteel
shales. The high angle reverse faults may coalesce at depth into a major detachment surface
possibly rooted in the highly attenuated Kechika formation. Shales typically have a pervasive
slaty cleavage that is axial planar to the macroscopic folds; a closely-spaced fracture cleavage is
found in the more competent strata.
The second phase of deformation folds the early slaty cleavage and develops a penetrative
crenulation cleavage. This cleavage is axial planar to the late folds, which may have an
amplitude of up to 30 metres (Pigage, 1986). The folds are open to upright, trend northwest and
have northeast vergence.
High-angle listric normal and reverse faults are also common in the Akie River area and
generally trend parallel or at slight angles to the major high angle thrust faults. These faults are
probably related to brittle failure of thrust plates during detachment and thrusting.
Displacements of up to several hundred metres have been documented at the Cirque deposit
(Pigage, 1986).
North to northeast trending high angle faults offset earlier thrust and listric normal faults. Some
of these faults have a strike-slip movement and may be synthetic shears related to an oblique
compressional stress regime. This compressional event is believed to be Tertiary in age.
7.3 Property Geology
The Akie claims are underlain by a northwest trending package of Devonian age shales,
siltstones and localized limestones and conglomerate which overlie Silurian age calcareous
siltstones of the Road River Group. This package of rocks is folded into a series of both
northwest and southeast plunging synforms and antiforms and is in thrust contact to the
southwest with Ordovician siltstones, shales, limestones, and minor pyroclastic volcanics of the
Road River Group.
- 29 -
The oldest rocks exposed on the property are the Ordovician aged Road River shales and
calcareous siltstones which form the ridge top along the west edge of the property. These rocks
occupy th e core of a westward dipping overturned anticline that has been thrust northeastward
over Earn Group rocks.The southwest and northeast flanks of this anticline are comprised of a
thick homogenous sequence of Silurian dolomitic siltstone. Overlying these siltstones is a
Devonian aged bioclastic limestone comprised of coral, crinoid, brachiopod and other fossil
debris in a medium grey limestone matrix. This limestone is also grouped within the Road
River, (MacIntyre, 1998). Macro fossil and Conodont age dates for the fossiliferous limestone
vary from early Middle to Upper Devonian.
Figure 7. Genetic model for formation of SEDEX deposits in the Gataga District. After
MacIntyre, 1998.
- 30 -
The Road River Group is overlain by the Middle to Upper Devonian Gunsteel Formation which
is a thick sequence of relatively featureless black siliceous shales, cherty argillites and cherts.
The shales are recessive and weather a characteristic gunsteel color. Cherty argillite and chert is
often graphitic with bedding marked by local zones of nodular barite and faint, very finegrained laminae of pyrite or rare laminations of siltstone. Within the Gunsteel Formation
mappable units of pinstriped shales and chert pebble conglomerate have also been outlined
(Baxter, 1996c). The pinstriped shales are a black shale package with thin creamy grey
laminations which are best exposed on weathered surfaces. A chert pebble conglomerate has
been mapped along the eastern edges of the property and may possibly have a close spatial
association with the bioclastic limestone. In its coarsest occurrence, the conglomerate is
comprised of 2 mm to 1 cm medium grey to creamy grey rounded chert pebbles which fines
upwards to 1-2 mm quartz and chert grains in a shale and silty matrix (Baxter, 1996c).
Exploration activity on the Akie property has been focused within a 400-600 m wide band of
black, recessive weathering shale of the Middle-Upper Devonian Gunsteel Formation which has
been covered by the main grid. These rocks occur as a narrow northwest trending southwest
dipping package which stratigraphically overlie Lower to Middle Devonian calcareous
siltstones, reefoidal limestones and limestone debris flows to the northeast. To the southwest the
Gunsteel rocks lie below a southwest dipping thrust plate comprised of an overturned,
southwest dipping anticline of Ordovician to Silurian siltstones, shales and limestones of the
Road River Group.
8.0 DEPOSIT TYPES
Gustafson and Williams (1981), Large (1981,1983), Morganti (1981) and others have reviewed
the geologic characteristics and genetic models for sedimentary exhalative deposits. The
physiochemical controls on formation of the deposits have been discussed by Finlow-Bates
(1980), Russell et al. (1981), Russell (1983), Lydon (1983), Lydon et al. (1986), and
Goodfellow and Jonasson (1986a,b). The consensus amongst these authors is that the deposits
form by precipitation of sulphide and sulphate minerals from metalliferous brines exhaled along
active submarine faults. Metals and fluids are most likely derived from the sedimentary pile
either by normal dewatering during basin subsidence or by hydrothermal leaching during
periods of elevated heat flow and convective circulation of seawater through the sedimentary
pile. These conclusions are consistent with the model proposed for formation of the deposits of
the Gataga district (Figure 7).
Bedded Pb-Zn+/-Ag deposits in the Gataga district have characteristics typical of the
sedimentary exhalative (SEDEX) deposit type as summarized in Appendix A. The most
economically important sedimentary exhalative deposits in the Gataga district are hosted by
basinal facies rocks the Gunsteel formation (MacIntyre, 1995, 1998). The host rocks are not
well exposed and baritic 'kill zones' and iron seeps are often the only surface indicators of
mineralization.
Both barren barite and mixed barite-sulphide deposit types occur in the district. This bimodal
distribution is also observed in the MacMillan Pass district of the Yukon (Dawson and Orchard,
1981). The sulphide bearing deposits such as Mt. Alcock, Cirque, Fluke and Elf, are restricted
to a belt of Gunsteel rocks bounded by the Akie reef to the east and uplifted Ordovician and
Silurian rocks to the west (Figure 5). The mineralogy of these deposits is simple; consisting of
pyrite with varying proportions of sphalerite and galena in a barite host. Framboidal pyrite can
- 31 -
be found in the least deformed deposits. Overall, copper content is very low with the exception
of one of the Pie showings which has some malachite staining.
The footwall rocks for the deposits are typically rhythmically bedded black cherts or
porcellanites, cherty mudstones, argillites and siliceous, carbonaceous shales with minor
siltstone and pelagic limestone interbeds. Laminae of pyrite and bands of barite nodules are
common near the deposits. The high silica, high carbon and low clastic content of these rocks
suggest that they were deposited in a restricted marine basin with very low sedimentation rates.
Plate 2. Cardiac Creek discovery showing. Photo taken by D.G. MacIntyre, August 26, 2005.
The massive barite or barite-sulphide deposits grade laterally into thin (less than 10 metres)
beds of carbonaceous, cherty mudstone and argillite that contain laminae and lenses of nodular
barite. This mineralized zone is widespread within the basin and is an important stratigraphic
marker. It typically occurs near the top of the Gunsteel formation where it is overlain by distal
turbidites of the Akie formation. The basal beds of the Akie formation often contain carbonate
nodules and pyrite laminae, particularly close to the barite-sulphide deposits. The stratigraphic
- 32 -
position of the mineralized horizon also coincides with the transition from starved basin
sedimentation, as represented by the Gunsteel formation, to a more open marine turbidite
environment, as represented by the Akie formation. This early Late Devonian change in
sedimentary environment is recognized throughout the Kechika Trough and Selwyn Basin and
coincides with the beginning of uplift to the west and the progressive onlapping of fine-grained
marine clastic sediments onto the carbonate platform to the east.
Sulphide and barite crystallinity and distribution vary from extremely fine-grained and
delicately laminated to relatively coarse-grained and massive. Where foliation is at an oblique
angle to bedding, barite becomes coarser grained with crystal growth parallel to foliation
planes. Where folding is intense, all primary structures are obliterated and the barite appears to
be completely recrystallized.
9.0 MINERALIZATION
In 1994, massive sulphide mineralization was discovered in gossanous outcrops in Cardiac
Creek. The stratigraphic position of this mineralization corresponds to the base of the Gunsteel
Formation. Mineralization occurs as centimeter scale layers of finely laminated, fine grained
pyrite, sphalerite and galena interbedded with barren black shales and cherty argillites of the
Gunsteel Formation. A continuous chip sample across the widest bed returned 16.0% Zn and
2.8% Pb over 40 centimetres. The discovery has been called the Cardiac Creek showing or
horizon which to date has been defined by drilling over a strike length of 1500m and tested to
depths of 700-800m below surface.
In 1995, a goniatite (ammonoid) fossil Alpinites cf. Kayseri was recovered from the massive
sulfides in hole A-95-16 at 613.5m. This particular fossil has a very limited age range of lower
to middle Famennian (upper Devonian). This would make the Cardiac Creek Horizon slightly
older than the Cirque deposit which has been dated using conodont biostratigraphy as Upper
Famennian (Paradis et al., 1998).
Coarse-grained sedimentary breccias occur in the stratigraphic footwall of the Akie deposit
suggesting the presence of growth faults within the host basin. Fragments from these breccias
contain early Frasnian and early Fammennian age conodonts; others have conodonts typical of
the Eifelian-Givetian boundary of the Middle Devonian (Paradis et al., 1998). The presence of
Middle Devonian conodonts in the breccias indicates erosion of old strata in Famennian or
younger time (Paradis et al., 1998).
Several nodular to bedded barite occurrences have also been documented on the property and
these occur within the most westerly panel of Gunsteel rocks (Baxter, 1996c). The most
significant of these has been called the Waterfall showing which occurs on the south side of the
Akie River on line 7600S at 175E. The Waterfall barite showing consists of a 8.5m thick
sequence of massive, siliceous black shale with 5-10% ultra fine grained disseminated pyrite
interbedded with 0.5-1.2m beds of nodular bedded barite with 10-15% pyrite laminations
(Baxter, 1996c). A zone of nodular barite associated with this showing can be traced north
across the Akie River to line 4600S where it lies just east of the baseline. The waterfall barite
showing may be equivalent to the Elf barite-galena showing approximately 7 km to the
southeast.
At the north end of the property two narrow nodular barite horizons are exposed on Fluke
Ridge. The lateral extent of the two horizons have not been established but it is possible the
- 33 -
more westerly horizon may be traceable grid south to line 1400S and 1600S where nodular
barite within shales has been observed within a creek and on a ridge.
9.1 Lithostratigraphic and mineralized units intersected in drilling
The following is taken from Vanwermeskerken and Metcalfe (2006) and pertains to the general
stratigraphy intersected in the 2005 drilling program
9.1.1 Upper Gunsteel shale
The upper half of the hangingwall stratigraphy consists of black, graphitic, massive, featureless
shales of the Upper Devonian Gunsteel formation. These rocks host various major faults and
are highly fractured and shattered. Many smaller faults and fracture planes with signs of
movement, are typically filled, or coated with graphite, and with graphite slickensides, often
highly polished.
9.1.2 Lower Gunsteel shale
A major fault separates the upper Gunsteel shale from a more competent, but equally
homogeneous, black, graphitic shale below, also of the Gunsteel formation. This lower shale
unit includes some weak siliceous zones but is generally featureless downhole to the strata near
the downhole contact. Calcite ± pyrite ± barite nodules, as large as 2 mm, define bedding
where laminae are not visible. These nodules are commonly somewhat flattened parallel to
bedding. The core typically parts along a well developed bedding-parallel cleavage, resulting in
'pokerchip' breakage in drill core. Within a few tens of metres from the footwall of this graphitic
unit, well-rounded, well-defined concretions as large as 5 cm are visible, scattered throughout
the shale.
9.1.3 Cardiac Creek unit
The Gunsteel shales grade downwards into a sequence of interbedded dark grey, massive,
weakly siliceous shale and well bedded to laminated, grey-green, siliceous, highly pyritic
siltstone that appears to contain significant amounts of barite. The contact itself is not well
defined, because the pyritic strata first appear as discrete beds, as much as 5 cm thick, gradually
increasing in abundance and thickness downsection to an overall abundance of as much as 80%
over intersections as long as a metre, with sulphide beds as thick as 50 cm. These beds appear
laminated grey-green when examining the drill core, with numerous laminae containing coarser
disseminated pyrite grains, and a whitish grey coloration where sphalerite (+galena)
mineralization occurs. On sawn surfaces the bands appear as shiny, massive, laminar pyrite. In
the lower parts of this unit, visible sphalerite and galena increase to as much as 25% and 3%
respectively although analyses returned indicate a much higher base metal sulphide content.
The sphalerite at Akie is difficult to discern, as it occurs as an inconspicuous, pale grey to very
pale bronze, very fine-grained aggregate, very similar in appearance to the shale and barite
gangue in all but the semi-metallic lustre of the sulphide. As much as 5% coarser grained black
sphalerite and galena were noted in drillholes A-05-32 and A-05-33.
Subrounded to subangular equant clasts as large as 8 cm, composed of coarse to banded dark
grey calcite, increase in abundance downsection. Deformation of the laminated pyritic unit also
increases downhole, as a result of the steadily increasing proportion of (structurally)
incompetent sulphide in the rock. The evidence of deformation is a penetrative cleavage, at low
angles to the core axis in sulphide beds only and detached “micronappe” folding of high
sulphide sections, including the thin shale interlaminae in such sections.
- 34 -
A thin (25 cm), very siliceous quartz-pyrite breccia was noted in two of the drillholes (A-05-30
and A-05-32). The breccia consists of fragmented silty shale in a matrix of quartz with as much
as 15% pyrite. The breccia zone, approximately 25 cm wide, grades from crackled margins to
matrix-supported centres with rotated fragments. The pyrite occurs mostly as rims as wide 3
mm on the margins of breccia clasts and as minor disseminations in both the clasts and the
matrix.
These breccia zone intersections are very consistent in texture and length of intersection and it
is possible that the same structure is intersected by both holes. The breccia occurs in the banded
unit in each of the holes, but at different levels with respect to the top of the zinc-rich stratiform
mineralization. It is therefore not directly related to the syngenetic mineralization and is
interpreted, for the present, as a cross-cutting structure.
A sharp footwall contact separates the banded sulphide/shale subunit from the underlying
layered barite-sulphide subunit. The latter is a variably laminated to massive, grey barite with
sulphide content as high as 50% grey sphalerite, 40-60% pyrite and 7% galena. It is commonly
diluted with minor, thin beds of black shale.
Footwall assemblage
The footwall rocks to the mineralized barite bed vary considerably and cannot be generalised.
These rocks seem to be a complex intercalated sequence of Road River sedimentary rocks and
minor Gunsteel shales, ranging from calcareous shale, to medium grey siltstone with pale grey
calcareous sedimentary breccia fragments, to dark grey, often-graphitic shale, believed to be of
the Gunsteel formation. This may represent a transitional facies from Road River to Gunsteel
deposition.
Brecciated zones within the footwall rocks (calcite-quartz-pyrite breccia) with sections hosting
massive pyrite are thought to be associated with the growth fault system feeding the mineralized
horizon.
10.0 EXPLORATION
The following information is abridged from reports filed for assessment credit by Inmet Mining
Corporation (Baxter, 1995, 1996, 1996a, 1996b). The writer has reviewed these reports and is
of the opinion that they accurately reflect the results of exploration completed on the Akie
property in 1994 through 1996. Work done as part of this three year program is summarized in
Table 3; exploration expenditures are shown in Table 2.
Also in 1995, baseline environmental studies were initiated and preliminary mineralogical
studies undertaken.
10.1 Soil Geochemistry
From 1994 to 1996, 95.85 km of grid was established on the Akie claims with a total of 3251
soil samples collected. The majority of the grid is at a 200 m spacing from line 600N to line
7600S and covers a 400-600 m band of the Gunsteel formation which hosts the Cardiac Creek
zone. Reconnaissance soil lines were run in 1995 as extensions of the main grid to evaluate
prospective Gunsteel stratigraphy to the east of the main grid area. Grid lines were established
using chain and compass, slope corrected and cleared of brush for ease of access. A summary
map of the soil geochemical data compiled by the writer from assessment report data is shown
- 35 -
in Figure 8. The following description of anomalous areas is taken from a compilation report by
Baxter (1996c).
Figure 8. Soil geochemistry, Akie Property. Map was compiled by D.G. MacIntyre from
company reports. Projection is UTM zone 10, NAD83.
- 36 -
10.1.2 Akie Main Grid
Relative to the rest of the property, the western panel of Gunsteel formation that is covered by
the Main grid is a highly anomalous shale package and has been the prime exploration target on
the property (Baxter, 1996c). The main grid covers the Cardiac Creek Horizon which occurs at
the base of the Gunsteel formation and any soil anomaly associated with this contact should be
considered significant. Several significant soil anomalies have also been defined in the Cardiac
Creek hanging wall and are associated with known barite occurrences. Following is a brief
description of the major multi-element soil anomalies from the main grid, some of which have
already been drill tested:
•
•
•
•
•
•
•
The south zinc anomaly is a 2000m x 500m area of soils containing highly elevated zinc
(up to 1.12% Zn) concentrations. This anomaly covers an area of Gunsteel shales that
are proximal to the Gunsteel shale-Limestone-Road River contact, a possible extension
of the Cardiac Creek horizon. Within this large zinc anomaly, two multi-element linear
trends have been defined by spotty single station Ba, Pb, Cd, Fe, Mn and As anomalies.
The South Zinc anomaly (Figure 8) is the largest untested anomaly on the property and
several drill holes are required to assess its significance.
The Fluke Ridge anomaly is a 1000m x 200m lead anomaly which overlies Gunsteel
shales with local internal barium, arsenic and iron anomalies. This anomaly is partially
associated with a narrow nodular barite horizon located on the top of Fluke Ridge as
well as potential Pb enrichment in the Cardiac Creek hanging wall which, due to
folding, the horizon is not exposed in this area. Hole A-96-24 tested this soil anomaly.
There is no mineralization in the hanging wall shales to explain the lead anomaly
however massive sulfide mineralization was intersected at the base of the Gunsteel
formation in this hole.
A 1800 m primarily Pb and Ba anomaly with spotty As, Ag, Cd, Zn and Fe associated
with the north end of the Cardiac Creek mineralization
A 1400m discontinuous anomaly made up of smaller Ba and Pb anomalies and spotty Fe
and Zn anomalies associated with baritic and pyritic Gunsteel shales in the hanging wall
of the Cardiac Creek horizon.
A 1600 m to 2200 m mainly Pb - Zn anomaly with smaller Ba, Cd, Fe, As, and Ag
anomalies representing the southerly strike extension of the Cardiac Creek zone and
metal enrichment within the immediate hanging wall. In 1996, this anomaly was drill
tested by three holes with fringe style mineralization intersected towards the southern
edge of the anomaly. There still remains 800m of this anomaly at its north end which
has not been drill tested.
Primarily a Ba - Pb anomaly with spotty Zn, As, Mn and Fe. The main portion of the
anomaly, from line 7200S to 7600S, which is associated with the Waterfall Barite
showing, has not yet been drill tested. This anomaly may be extrapolated across the
Akie River where a Ba, Pb, Zn, As, Mn and Fe anomaly occurs on lines 6000S and
6200S. This anomaly is also associated with nodular barite occurrences and has a weak
continuation north to line 5200S which has been partially tested by the tops of holes 20
and 27 with no significant mineralization intersected.
Mainly a Mn anomaly from line 7000S to 7600S with spotty Zn. This anomaly occurs
along the Gunsteel - Road River contact with spotty enrichment within the Road River.
This anomaly was drill tested by hole A-96-23 with no significant mineralization
intersected.
- 37 -
10.1.2 Akie Reconnaissance Grid:
Five anomalous areas have been identified on the reconnaissance grid, some of which will
require additional mapping, prospecting, line cutting and soil sampling to assess their
significance and define suitable drill target. These anomalies are;
•
•
•
•
•
A 400 m Pb, Zn, As, Fe and Cd anomaly on lines 400S to 800S below the 1995/96 core
shack. Exposure in this area is fairly good and additional mapping and prospecting may
explain this anomaly.
A 1000 x 200m Zn, Ba and Cd anomaly on line 00N to 1000N. Diamond drilling is
required to test this anomaly.
A 400-500 m Pb, Zn, Ba, Fe, Mn and Cd anomaly on line 1400S in the Silver Creek
area along a shale -limestone contact, a possible time equivalent of the Cardiac Creek
horizon. Diamond drilling is required to test this anomaly.
An Ag, Mn and Cd anomaly within Gunsteel shales on line 800S.
A 600m Ag, As, Mn anomaly in Gunsteel shales on line 2600S.
10.2 Lithogeochemistry
In conjunction with the mapping and prospecting of the property, 284 whole rock
lithogeochemical samples have been collected to identify areas of elemental enrichment or
depletion which may be a result of hydrothermal activity responsible for massive sulfide
development. Samples have been analyzed for major and trace elements using ICP and atomic
absorption methods at Min-En Labs of Vancouver. The following is a brief summary of
anomalous areas as identified by Baxter (1996c)
From line 4600S to 6400S, representing the southerly strike extension of the Cardiac Creek
horizon, is a 1800m x 200m zone of enriched Ba, Pb, TI, Hg, Si02, spotty Zn, Cd and Ag with
footwall As enrichment in the Road River. This area was tested by holes 20, 22 and 27. Hole 20
intersected a mineralized fault zone and hole 22 intersected fringe style mineralization near the
Cardiac Creek horizon. Lithogeochemical samples from these drill holes show a similar
lithogeochemical enrichment pattern as seen on surface.
•
•
•
•
From line 2600S to 4200S, a 1600m x 300m zone of enriched Ba, Zn, Cd and spotty Ag
within the hanging wall of the known mineralization of the Cardiac Creek zone plus As
enrichment within footwall Road River siltstones.
An 800m x 100m Ba, Zn, Ag and minor Hg anomaly in the hanging wall of the Cardiac
Creek horizon associated with baritic pyritic siliceous shales. This anomaly is untested
by drilling.
A 500m Ba, Pb, TI, Hg with spotty Zn and Cd anomaly associated with the Waterfall
barite showing. This anomaly can be extended across the Akie River along the base line
to line 3800S (2600m) through 100 - 400m anomalies of Ba, TI, Hg, Si02 and spotty
Ag, Pb and Zn which are also associated with known nodular barite occurrences. Part of
this anomaly was tested by the top of hole 27 which did intersect 19.2m of shale with
nodular barite which shows zinc enrichment to 0.13% and up to 15.7% Ba.
Litho sampling in 1996 in the south zinc soil anomaly area also shows this area to be
enriched in Zn and TI with spotty Hg, Pb, Ba and As. This area shows both soil and
whole rock multi-element enrichments and to date has not been drill tested.
- 38 -
Figure 9. Geology and 1994-1996 drill hole locations, Akie property. Map compiled by D.G.
MacIntyre from company reports. Projection is UTM zone 10, NAD83.
10.3 Geophysics
In 1994 and 1995 all of the main grid and selected reconnaissance lines were covered by a
VLF-Resistivity survey to:
- 39 -
1. From the differences in resistivities, trace the Gunsteel Shale - Road River calcareous
siltstone contact, along which mineralization occurs, across the property.
2. Act as a mapping tool to aid the tracing of other lithologies across the property.
Both the 1994 and 1995 surveys were conducted by Pacific Geophysical Limited of Vancouver,
BC. The VLF-Resistivity survey was found to be a very useful mapping tool to help trace
various lithologies across the property (Baxter, 1996c). There is sufficient contrast in resistance
between the Gunsteel shales (very low resistivity) and the Road River calcareous siltstones
(high resistivity) to easily distinguish between these two rock types and thus trace the Cardiac
Creek time horizon across the property.
11.0 DRILLING
The following section describes drilling activities on the Akie property and has been compiled
by N. Johnson, project geologist for Coast Mountain Geological Ltd.
11.1 Inmet drill programs (1994-1996)
The following is an abridged version of drilling activities carried out by Inmet Mining from
1994 to 1996. Assessment reports 23870, 24323, 24439, and 24703 (Baxter 1995, 1996, 1996a,
1996b) provide a detailed review of drilling and include drill logs, analytical results,
interpretation and conclusions. These reports can be obtained in PDF format from British
Columbia’s
Ministry
of
Energy
and
Mines
ARIS
website
at
http://www.em.gov.bc.ca/mining/Geolsurv/Aris/default.htm. A summary of Inmet Mining’s
exploration activities, including drilling, is presented in the initial 43-101 report on the Akie
property in 2005 by D.G. MacIntyre (MacIntyre, 2005).
From 1994 to 1996, Inmet Mining completed 29 drill holes totalling 13,685.5m. The details of
these drill holes can be found in Table 3 and the drill holes can be located in Figure 9. This
drilling established a relatively simple sequence of geology to be encountered down hole. In
cross section, the rocks of the Road River Group, late Ordovician in age, consisting of an
undifferentiated package of intercalated shales, silty shales, siltstones and muddy limestones
(MacIntyre, 2005) are in thrust contact with the younger rocks of the Gunsteel Formation. The
thrust fault, a zone of brittle deformation is marked by extremely poor ground conditions
characterised by numerous sections of graphitic gouge, rubble, brecciation and quartz-carbonate
healed faults.
The rocks of the middle to late Devonian Gunsteel Formation are the prospective rocks
currently being explored on the Akie property. These rocks are several hundred meters in
thickness and consist of very fine grained, “jet” black shales that are siliceous and variably
graphitic. Inmet Mining also identified sections of cherty argillites as well. Brittle faulting cuts
through the shales with consistency although in decreasing abundance away from the overlying
thrust fault. The Gunsteel shales are also host to sections of exhalative mineralisation in the
form of very fine grained, laminated dull brown pyrite interbedded with the shale. These
sections can be several ten’s of centimetres in width and occur over ten’s of metres. The
Cardiac Creek Zone (CCZ) is located proximal to the contact with the underlying Road River
Group rocks. Situated typically at the contact between the Gunsteel Formation and the Road
River Group is a breccia or debris flow consisting of millimetre to centimetre scale angular to
subrounded clasts of shale, limestone to fossiliferous limestone, calcareous siltstone to
laminated siltstone. The contact between the breccia and the Road River Group is gradational
although occasionally it can be faulted. The underlying Road River Group rocks are similar in
- 40 -
nature to those situated at the top of the sequence with a package of undifferentiated calcareous
siltstones, silty shales, shales to bioturbated shales. This idealised geology can be seen in cross
section in Figure 10.
Table 3. Summary of Inmet and Mantle drill holes, Akie Property.
HOLE
ID
GRID
S
GRID
W
UTM N
(m)
UTM E
(m)
ELEV
(m)
AZIMUTH
(°)
DIP
(°)
LENGTH
(m)
INMET MINING DRILL HOLES
A-94-01
1925
50E
6361324* 387814*
1475*
050
-55
262.40
A-94-02
2380
190E
6361098
388230
1545
050
-54
178.90
A-94-03
3800
100E
6359895
389067
1252
050
-54
233.50
A-94-04
3800
100E
6369895
389067
1252
050
-73
296.00
A-94-05
3400
110E
6360212
388806
1345
050
-65
230.70
A-94-06
4200
80
6359460
389162
1298
050
-57
540.70
A-94-07
3400
110E
6360211
388806
1344
050
-87
272.80
A-94-08
2382
35E
6360997
388101
1624
050
-55
203.00
A-94-09
2382
35E
6360997
388101
1624
050
-85
350.80
A-94-10
2858
20E
6360601
388381
1572
050
-49
294.70
A-94-11
2858
20E
6360600
388381
1570
050
-78
370.90
A-94-12
3400
75
6360101
388660
1429
050
-71
518.80
A-95-13
3083
190
6360290
388263
1526
050
-82
818.40
A-95-14
3390
285
6359973* 388482*
1528*
055
-79
124.10
A-95-15
3390
285
6359973* 388482*
1528*
055
-84
578.20
A-95-16
3820
135
6359741
388866
1355
050
-83
741.30
A-95-17
2400
350
6360735
387802
1726
055
-87
829.10
A-95-18
3385
407
6359884
388376
1559
055
-87
1030.50
A-95-19
2830
570
6360243
387917
1655
035
-88
1192.40
A-96-20
5202
19E
6358726
389904
1074
050
-60
438.30
A-96-21
3025
287E
6360657
388702
1424
203
-84
601.10
A-96-22
6209
250E
6358163* 390641*
943*
050
-50
282.90
A-96-23
6970
462E
6357713* 391278*
890*
050
-50
206.70
A-96-24
400
150
6362387
386687
1587
050
-60
541.90
A-96-25
780
085E
6362221
387128
1456
050
-45
214.60
A-96-26
780
085E
6362219* 387124*
1480*
050
-87
129.50
- 41 -
HOLE
ID
GRID
S
GRID
W
UTM N
(m)
UTM E
(m)
ELEV
DIP
(m)
AZIMUTH
(°)
(°)
LENGTH
(m)
A-96-27
5600
0E
6358400
390135
994
070
-62
593.80
A-96-28
3510
328E
6360288
389046
1229
230
-70
211.80
A-96-29
3510
328E
6360288
389046
1230
230
-75
1262.20
MANTLE RESOURCES DRILL HOLES
A-05-30
3275
150
6360161
388557
1484
050
-78
599.00
A-05-31
3050
205
6360296* 388366*
1543*
060
-70
132.50
A-05-32
3050
205
6360292
388366
1526
055
-68
638.40
A-05-33
3480
145
6360006
388693
1398
060
-77.50
629.00
A-06-34
3275
145
6360165* 388550*
1497*
050
-86
330.50
A-06-35
3275
145
6360165* 388550*
1497*
050
-74
696.00
A-06-36
3050
205
6360291
388364
1527
055
-80
75.29
A-0636A
3050
205
6360291
388364
1527
055
-80
791.67
A-06-37
3050
205
6360296* 388366*
1543*
055
-65
24.99
A-0637A
3050
205
6360292
388365
1526
055
-65
593.45
A-06-38
2875
200
6360435
388260
1603
055
-70
599.55
A-06-39
3275
145
6360165* 388550*
1497*
055
-72
15.40
A-0639A
3275
145
6360165* 388550*
1497*
055
-71.5
542.24
A-06-40
3480
145
6360005
388691
1398
055
-73
535.54
A-06-41
3480
145
6360005
388691
1398
055
-83
675.74
A-07-42
2875
205
6360435
388260
1603
060
-80
712.02
A-07-43
3400
105
6360100
388659
1430
055
-81
629.72
A-07-44
5800
1345E
6359179
391309
1269
230
-65
221.04
A-07-45
3400
105
6360101
388659
1429
040
-78
584.00
A-07-46
2645
205
6360603
388109
1720
069
-74
730.61
A-07-47
3275
55
6360219
388623
1443
055
-72
401.12
A-07-48
2928
75
6360464
388380
1544
063
-68.5
446.84
A-07-49
3135
75
6360311
388522
1439
060
-64
387.71
A-07-50
3275
145
6360160
388554
1485
025
-78
587.22
- 42 -
HOLE
ID
GRID
S
GRID
W
UTM N
(m)
UTM E
(m)
ELEV
DIP
(m)
AZIMUTH
(°)
(°)
LENGTH
(m)
A-07-51
2928
75
6360464
388380
1544
063
-80
513.90
A-07-52
2941
345E
6360732* 388719*
1424*
205
-63
852.00
A-07-53
3135
75
6360311
1438
060
-79
460.08
388522
Note: UTM coordinates, NAD83, Zone10
Of the 29 drill holes 22 of them intercepted and defined the mineralisation now known as the
CCZ. The mineralisation associated with the CCZ is a planar, tabular body of mineralisation
striking 130° to the SE and dipping 70° to the SW. It has a strike length of roughly 1500m and a
dip extent of 700m and is characterised by pyrite, sphalerite and lead enriched sulphide beds
tens of centimetres to metres in width interbedded with siliceous shale beds. Significant
intercepts from these drill holes are given in Table 4. These drill holes defined the horizon of
mineralisation which was to be later tested by Mantle Resources. Utilising higher grade
intervals present in holes A-94-11, A-94-12, A-95-13 and A-95-18 that averaged 8.0 to 9.2 %
zinc and 1.3 to 1.8% lead over 7m Inmet Mining produced a preliminary resource figure on the
order of 12 million tons grading 8.6% zinc, 1.5% lead and 17.3g/t silver (MacIntyre 2005,
Baxter 1996)
11.2 Mantle Resources drill programs (2005-2007)
In late 2005 Mantle Resources conducted a short 4 hole drill program designed to once more
test the CCZ targeting and infilling the central area defined by the 4 drill holes used by Inmet
Mining to produce their preliminary resource figure. Of the 4 drill holes only 3 were completed
and 1 abandoned. A total of 1369.90m were drilled. The results from holes A-05-30, A-05-32,
and A-05-33 redefined the nature of the CCZ in that there appeared to be a much higher grade
central core or lens in the panel of mineralisation initially discovered and defined by Inmet
Mining. The results of these three holes are given in Table 4 and their longitudinal section
pierce points are shown on Figure 11. Drill hole locations are shown on Figures 12 and 13.
Drilling resumed on the Akie property late spring of 2006 with the primary objective to
determine the nature of the newly discovered high grade core of the CCZ. To this effect, drill
targets focused on testing the high grade core both up and down dip of the 2005 intercepts. A
total of 8 drill holes intercepted the CCZ, although 3 of them had to be restarted due to poor
ground conditions, equating to a total of 4880.37m of drilling.
The results demonstrated that the high grade core, both up and down dip displayed a slight
decrease in the overall zinc and lead grades with the widths of mineralised intercepts being
preserved. In addition, the pierce points seemed to indicate that the high grade core was aligned
along a specific axis with a shallow 10°-15° plunge to the SE. The results of this drilling
program can be found in Table 4 and the longitudinal section pierce points are shown on Figure
11.
- 43 -
Figure 10. Idealized geological cross section 3400S, Akie Property. Source: Mantle Resources
Inc.
- 44 -
Figure 11. Cardiac Creek Zone pierce points in vertical long section view.
Table 4. Summary of significant drill intersections, Akie property.
HOLE
ID
FROM
(m)
TO
(m)
LENGTH ZONE
(m)
Zn
(%)
Pb
(%)
Ag
(g/t)
Zn+Pb
(%)
INMET MINING DRILL HOLES
A-94-01
109.40
113.10
3.90
CCZ
Silicified baritic shales
No Significant Results
A-94-02
A-94-03
163.90
172.70
8.80
CCZ
2.73
0.46
4.05
3.19
A-94-04
238.30
247.00
8.70
CCZ
2.91
0.50
5.83
3.41
A-94-05
132.30
145.40
13.10
CCZ
3.54
0.61
5.04
4.15
No Significant Results
A-94-06
A-94-07
189.90
232.10
42.30
CCZ
4.75
0.83
8.36
5.58
A-94-08
173.90
179.80
5.90
CCZ
2.47
0.40
6.97
2.87
A-94-09
308.80
314.40
5.60
Laminar massive pyrite interbedded with shale
No Significant Results
A-94-10
A-94-11
337.20
353.30
16.10
CCZ
5.40
1.11
8.49
6.51
A-94-12
443.20
470.80
26.20
CCZ
5.46
1.07
10.37
6.53
A-95-13
663.80
671.50
7.70
HW
2.86
0.50
6.49
3.36
- 45 -
HOLE
ID
FROM
(m)
TO
(m)
AND
701.40
734.10
LENGTH ZONE
(m)
32.70
CCZ
Zn
(%)
Pb
(%)
Ag
(g/t)
Zn+Pb
(%)
5.52
1.08
10.45
6.60
A-95-14
Hole Abandoned
A-95-15
Hole Abandoned
A-95-16
625.30
659.90
34.60
CCZ
2.47
0.49
6.20
2.96
A-95-17
658.00
662.10
4.10
HW
1.28
0.19
5.66
1.47
AND
681.20
683.40
2.20
CCZ
1.86
0.30
6.70
2.16
A-95-18
926.20
939.90
13.70
HW
2.50
0.40
5.86
2.90
AND
978.50
997.90
19.40
CCZ
5.14
0.88
9.78
6.02
A-95-19
1074.50
1077.40
2.90
CCZ
1.34
0.31
7.25
1.65
A-96-20
391.20
392.70
1.50
CCZ?
3.59
1.54
9.40
5.13
0.06
3.20
1.42
9.05
3.50
20.65
Hole Abandoned
A-96-21
A-96-22
172.70
174.40
1.70
CCZ?
1.36
No Significant Results
A-96-23
A-96-24
472.40
473.2
0.80
A-96-25
169.50
177.10
7.60
MS?
11.60
Bedded barite interbedded with shale
A-96-26
No Significant Results
A-96-27
No Significant Results
A-96-28
Hole Abandoned
A-96-29
No Significant Results
MANTLE RESOURCES DRILL HOLES
A-05-30
534.75
568.80
34.05
CCZ
11.87
2.83
23.98
14.70
Hole Abandoned
A-05-31
A-05-32
555.20
581.90
26.70
CCZ
11.96
2.73
22.23
14.69
A-05-33
558.55
577.75
19.20
CCZ
8.71
1.83
16.01
10.54
1.80
16.03
10.71
Hole Abandoned
A-06-34
A-06-35
642.70
664.60
21.90
AND
A-06-37
8.91
Hole Abandoned
A-06-36
A-0636A
CCZ
673.50
687.20
13.70
HW
4.03
0.76
7.40
4.79
711.40
721.80
10.40
CCZ
5.81
1.19
11.21
7.00
Hole Abandoned
- 46 -
HOLE
ID
FROM
(m)
TO
(m)
LENGTH ZONE
(m)
A-0637A
500.20
525.70
25.50
A-06-38
528.35
552.40
24.05
Zn
(%)
Pb
(%)
Ag
(g/t)
Zn+Pb
(%)
CCZ
8.35
1.73
16.36
10.08
CCZ
7.78
1.35
14.17
9.13
Hole Abandoned
A-06-39
A-0639A
490.00
508.10
18.10
CCZ
8.07
1.62
14.15
9.69
A-06-40
480.00
510.40
30.40
CCZ
5.49
0.86
10.69
6.35
A-06-41
587.60
604.35
16.75
CCZ
6.56
1.20
12.20
7.76
A-07-42
632.77
658.54
25.77
HW
3.87
0.58
4.42
4.45
AND
666.90
678.22
11.32
CCZ
13.83
3.24
21.11
17.07
A-07-43
544.20
571.81
27.61
CCZ
12.20
2.99
20.01
15.19
A-07-45
508.39
545.40
37.01
CCZ
13.91
3.07
22.94
16.98
A-07-46
630.03
657.39
27.36
HW
2.46
0.33
4.90
2.79
AND
671.00
673.12
2.12
CCZ
8.58
1.86
14.67
10.44
A-07-47
353.13
380.20
27.07
CCZ
9.63
1.83
13.69
11.46
A-07-48
384.57
419.71
35.14
CCZ
5.86
1.13
9.16
6.99
A-07-49
332.38
352.57
20.19
CCZ
11.41
2.24
15.36
13.65
A-07-50
525.38
554.78
29.40
CCZ
13.14
2.64
20.95
15.79
A-07-51
463.37
498.98
35.61
CCZ
10.60
1.80
15.10
12.40
AND
503.55
507.80
4.25
MS
10.99
0.92
21.49
11.91
A-07-52
741.00
744.00
3.00
CCZ
2.20
0.15
5.70
2.35
A-07-53
389.50
417.35
27.85
CCZ
9.70
1.84
16.01
11.54
Note that the “Length” is the core length. CCZ: Cardiac Creek Zone, HW: Hanging Wall Zone, MS: Massive
Sulphide.
- 47 -
Figure 12. Drill hole plan showing location of 2005-2007 drill holes. Map plotted by D.G.
MacIntyre from company drill hole survey information. See Figure 9 for geological legend.
In addition to the analytical results the drilling provided significant information with respect to
the mineralisation and down hole geology. As a result the mineralisation was broken into three
distinct mineralised facies and a detailed stratigraphic section of the Gunsteel Shale and its
various sub-units were constructed. The stratigraphic units and mineralised facies are described
below and can be seen in Figure 14.
- 48 -
Figure 13. Detailed drill hole plan, Cardiac Creek zone. Map plotted by D.G. MacIntyre from
company drill hole survey information.
The sub-units of the Gunsteel Shale are described as follows.
Shale: The shale or Gunsteel shale is commonly referred to as a mudstone, shale or argillite. It
is comprised of a very fine grained mud, “jet” black in colour, variably graphitic but generally
rich in carbon. The shale is bedded though due to the fine grained nature of the rock it is
commonly unobservable and exhibits a prominent cleavage oriented parallel to sub parallel to
the bedding. Fine grained bright brassy yellow pyrite is commonly disseminated throughout the
shale. This shale forms the basis of the other sub units within the Gunsteel Shale.
Silty Shale: The siltstone shale is comprised of the shale with interbeds of light grey very fine
grained to fine grained “limy” mud to silt. These beds are thin, ranging from a few to tens of
centimetres thick and are calcareous. Fine grained cubic bright brassy yellow pyrite
disseminated within these beds is common. The boundaries of this unit are subjective at best.
Fragmental Shale: The fragmental shale is what appears to be a sedimentary breccia or debris
flow and is characterized by scattered angular to sub angular fragments, ranging from
millimetres to several centimetres in size and composed of shale and calcareous siltstone which
may or may not be laminated or bedded. This unit is typically several to a couple tens of metres
thick bounded by the general appearance or absence of fragments.
- 49 -
Figure 14: Idealized stratigraphic section of Akie property down hole geology. Source: Mantle
Resources
Baritic Shale: The nature of the baritic shale associated with the CCZ is described below under
Property Mineralization. However, additionally, there is distinct sub-unit of baritic shale
occurring within the upper segment of the Gunsteel shale characterized by faint ovoid, off white
barite nodules, millimetres in size, oriented along bedding planes and are variably replaced by
carbonate. The sub-unit is few to several metres in thickness and is easily overlooked. This unit
is not associated with further mineralization.
- 50 -
Pyritic Shale (Distal), Bedded Pyritic Shale (Proximal), Cardiac Creek Zone (Main/CCZ):
The sulphide rich sub units of the Gunsteel Shale are described in detail below under Property
Mineralization but are included as a sub-unit of the Gunsteel Shale as they represent time
horizons as well as mineralogical facies
The mineralization associated with the CCZ can be broken down into three distinct facies;
Distal, Proximal and the Main/CCZ. The CCZ is typically underlain by barite rich shale. These
facies are:
Distal: The distal facies occurs in the hanging wall to the CCZ as well as separate, variably
spaced, distinct horizons located in hanging wall several hundred metres above the CCZ. This
facies can be characterized as a horizon occurring over widths from as little as a few to
approximately one hundred metres, though commonly 10 to 30 m in width. The mineralization
occurs within bands, 10 to 50 centimetres in width comprised of very fine grained, less than
millimetre scale laminations of dull brown pyrite and “trains” of white to off white nodular
barite, both interbedded with equally thin laminations of “jet” black carbonaceous shale. The
nodules are small, averaging a few millimetres in diameter, typically deformed to an ovoid
shape with their long axis oriented parallel to sub parallel to the bedding, and predominantly
have been, or are in the process of being replaced by carbonate often displaying a pyritic core.
These bands are interbedded with barren shale at the larger scale. Associated with the distal
facie are dark grey, variably sized from centimetre to greater than 10 centimetres in diameter,
spherical to ovoid, calcareous concretions.
In terms of elemental concentrations this facies is enriched in barium, iron and anomalous in
zinc with values up to 0.5% Zn. Lead is not present in any significant quantity.
Proximal: The proximal facies is situated directly above the main zone of the CCZ typically 10
to 20 m in thickness and represents the upper contact of the CCZ. The facies is characterized by
large, 10 centimetres to metre wide beds, internally comprised of less than millimetre wide
laminations, dominated by very fine grained, dull brown pyrite with minor “steel” grey matte
sphalerite. There is little to no galena present. These sulphide beds are interbedded with equally
wide beds of the “jet” black very fine grained shale typical of the Gunsteel Formation. The
nodular barite described above is present in the same manner though in decreased quantity.
Also present are the calcareous concretions described above in similar quantity and manner.
The contact between the proximal facies and the main facies of the CCZ is gradational in nature
marked by a gradual increase in sphalerite and an associated increase in galena.
In terms of the key elemental concentrations the proximal facies is enriched in iron and displays
a gradual increase in both zinc and lead with values ranging from 1% to 3% Zn and 0.25% to
0.75% Pb. There is a decrease in barite concentration.
Main (Cardiac Creek Zone): The main zone represents the richest portion of the CCZ zone in
terms of zinc, lead and silver and is commonly greater than 20 m in thickness. It is similar in
nature to the proximal facies however the sulphide beds are up to 3 m in thickness and the shale
interbeds are thinner, generally less than a metre in width. The sulphide beds are dominated by
very fine grained “steel” matte grey sphalerite and dull brown pyrite. The galena is coarser
grained and associated with blebs of carbonate predominantly disseminated throughout the
main zone, although there are rare occurrences of thin laminations of galena. Progressing
through the zone from top to bottom the nature of the sulphide beds change from predominantly
internally laminated to partially disrupted and semi-massive. Dark gray calcareous concretions
are present though in decreased abundance in comparison to the other facies. With the decrease
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in concretions there is an appearance and corresponding increase of angular to subangular,
variably sized, internally laminated to bedded sulphide rich clasts or fragments interpreted to be
rip up clasts. Elemental concentrations in the main zone are economic with zinc values reaching
30% and averaging 8% to 20%. Lead values can be on the order of 7% averaging 2% to 3%.
Silver values range from 15g/t to 30g/t. There is still a significant enrichment in iron and
increasing concentration of barium towards the base of the facies. Other elements enriched
within the facies of note are thallium, cadmium, strontium.
Situated directly beneath the zone is a barite rich shale characterized by massive beds of fine
grained white to tan white barite variably interbedded with beds of very fine grained dull brown
pyrite and or the Gunsteel shale changing to a mix of massive beds with “trains” of nodular
barite or simply concentrated bands to scattered bands of nodular barite. The barite is most
concentrated directly below the main zone and decreasing in abundance progressing down
through the stratigraphy.
In preparation for the 2007 drilling program the analytical results were used to further the
earlier work of John Kapusta involving using various elements and elemental ratios contoured
on a vertical long section in order to determine a potential direction to a source vent of the
mineralising fluids (Kapustra, 1995). Kapusta’s work identified two seemingly distinct trends,
one along strike to the NW and one down dip, located between the intercepts of A-95-13 and A96-17. The updated work was inconclusive, though, in general it supported a potential vent
location along strike to the NW.
The 2007 drilling program was primarily designed to define and test the limits of the CCZ in
order to provide sufficient information to generate a 43-101 compliant inferred resource figure.
To this end, drilling focused on testing the up dip extent of the mineralisation, infill some
sections within high grade axis to demonstrate continuity and step out to the NW and up-plunge
of the high grade axis. There were a total of 12 drill holes totalling 6526.26m completed in
2007, 11 of which intercepted the CCZ and 1 drill tested a large zinc soil anomaly to the SW
previously defined by Inmet Mining.
The results from the 2007 drilling were deemed by Mantle to have been quite successful with a
few unexpected surprises. In testing the up-dip extent of CCZ it was expected to encounter a
progressive decrease in both grade and thickness comparable to results in holes A-94-11 and A94-12. In the three holes drilled in this area only one was comparable - A-07-48, holes A-07-47
and A-07-49 both displayed similar grades and thickness to those along the high grade axis
(Table 4). Drill holes, A-07-43, A-07-45, A-07-50 and A-07-53 all tested the continuity of high
grade mineralisation within and along the high grade axis achieving results similar to and
exceeding the initial results obtained in 2005. Stepping out the NW and up-plunge returned a
mixture of unexpected but positive results. Hole A-0-51 was designed to step out along strike
from the intercept in A-05-32 and up-plunge. The mineralization encountered confirmed the
extension of the high grade axis. However situated stratigraphically below the CCZ and the
carbonate breccia, straddling the contact between the breccia and the underlying rocks of the
Road River group was a 3.63m section of massive sulphides faintly bedded enriched in
predominantly pyrite, sphalerite and galena. Holes A-07-42 and A-07-46 were also designed to
obtain pierce points up-plunge of the high grade axis however they both deviated from their
intended targets resulting in pierce points at a lower elevation. Rather than returning lower
grade mineralization both of these holes returned high grade mineralisation similar in nature to
the high grade axis though at narrower widths. In addition both of these holes intercepted the
HW zone previously observed in holes A-06-36A, A-95-13, and A-95-18.
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12.0 SAMPLING METHOD AND APPROACH
The following description of sampling method and approach was provided by Nick Johnson,
project geologist for Coast Mountain Geological Ltd.
Work completed on the Akie property is described in the various assessment reports and
internal reports. A review of these reports suggests that rock samples collected from the
property were either random grab samples or chip samples over a specific width. With respect
to the Inmet drill core an examination of the core remaining on the property indicates that only
the mineralised intervals were split and sampled. These intervals were removed from the
property and stored in a warehouse in Vancouver (Chris Graf, personal communication).
Examination of drill logs indicates the core was sampled in intervals ranging from 0.20m to
2.50 m. The length of sample intervals appears to have been determined by the amount and type
of sulphide present with shorter intervals taken within the massive sulphide zone.
Mantle Resources implemented a stringent procedure with regards to the sampling methodology
and preservation of the sampling record. The steps outlined below describe this procedure.
1. The drill core is flown to camp typically in bundles of 8 core boxes.
2. A geo-technician prepares the boxes of core for the geologist by measuring the “from”
and “to” down hole distance of each box marked on the upper left hand corner and
bottom right hand corner of each box. This information, box numbers and drill hole
number are recorded on an aluminium tag and stapled on the left end side of each box.
3. The geologist records his or her observations into a predefined drill log format in
Microsoft Excel under headings such as lithology, mineralization, structure, RQD,
alteration, sampling, etc.
4. Sampling is at the discretion of the geologist who is instructed to sample all observed
exhalative mineralisation and any other observed features of interest for exploration
purposes however sampling not to cross but abut against lithological boundaries.
5. Sampling is typically restricted to a minimum of 30cm and a maximum of 1.50m. The
beginning and end of a given sample are marked by a lumber crayon. Sample
boundaries and sample number are marked with a permanent marker on the wooden
divider of the core box just above the sample. Sample boundaries are also marked by an
aluminium tag stapled to the core box. Sample number, from and to distance and project
are recorded on a paper sample tag, the sample number is also recorded on an
aluminium tag and both are stapled to the core box at the beginning of a sample.
6. Sampling within the CCZ is generally limited to about 1m +/- 20cm as determined by
sulphide content.
7. QA QC procedures are in place during sampling of the drill core. A series of standards,
blanks and duplicates are inserted in the sample stream every ten samples. Each with
their own sample number.
8. Once all of the geologist’s observations and sampling has been recorded the core boxes
are then photographed in order to obtain a visual record of the drill core as well
including the samples taken.
9. The remaining paper sample stubs are kept and stored for record purposes
- 53 -
As shown above, Mantle developed an extensive set of guidelines for core handling, core
sampling, and sample tagging and shipment. The guidelines and procedures were reviewed by
Mr. Sim during his site visits in 2007. Sample practice adhered to the established procedures
and was in accord with industry standard practice. Adherence to the procedures produced
samples that are representative of the geologic environment and mineralization and are free
from any bias. There are no drilling, sampling, or recovery factors that would adversely affect
the resource estimation.
13.0 SAMPLE PREPARATION, ANALYSES AND SECURITY
13.1 Site Visit
Robert Sim has visited the Akie property on October 16-17, 2007. This time was spent at the
camp reviewing drill core and data recording practices. Unfortunately, poor weather conditions
did not allow for access, via helicopter, to drilling activities located some 5km from the camp
site. The property was also visited by D.G. MacIntyre on August 26, 2005.
The site visit by Robert Sim included a detailed review of the data stream from logging, to
database entry, to section plotting and, finally, rechecking of information with respect to the
surrounding geologic interpretation. Mr. Sim was impressed by Mantle’s site personnel and
activities during his site visit. The camp and facilities are extremely clean and well organized.
Site personnel follow an effective and methodical approach to processing the drill core being
generated. Mr. Sim also inspected the core sampling facility and equipment which was found
to be clean, organized and appeared to be in good working condition. Mantle site activities are
being conducted in a professional manner resulting in a quality product in all areas. The
equipment and practices reviewed during the site visit follow accepted industry standards.
13.2 Sample Preparation and Analysis
Assessment reports reviewed by the writers indicate the 1994 to 1996 analytical work was done
at IPL International Plasma Laboratories Ltd. in Vancouver B.C. These reports also include
copies of the original assay certificates and a description of analytical procedures used by IPL.
The writer has no reason to believe that sample preparation and security were not done in an
appropriate manner, following industry best practices applicable at the time.
International Plasma Laboratory Ltd is officially registered with and certified by the BC
Ministry of Environment, Lands and Parks (BCMOE) and the Canadian Association for
Environmental Analytical Laboratories (CAEAL). IPL’s analytical procedures comply with the
applicable requirements of the BCMOE, Environment Canada, American Society for Testing
and Materials (ASTM), American Water Works Association (AWWA) and United States
Environmental Protection Agency (USEPA).
Standard sample preparation for rock samples involves logging the sample into the laboratory
sample tracking system, drying, crushing, and pulverizing the entire sample so that greater than
80% passes a 75-micron screen. Trace elements were determined by leaching a sample aliquot
in Aqua Regia with an analysis by inductively coupled plasma (ICP) emission spectrometry and
mass spectrometry. International Plasma Laboratory maintains an internal quality control
program including the use of blank, duplicate, and standard samples inserted into the sample
- 54 -
stream. IPL sample preparation and analytical methods are deemed by the author to conform to
reasonable data verification controls.
Analytical work for the 2005, 2006 and 2007 drilling programs was done by ACME Analytical
Laboratories (Vancouver) Ltd., 1020 Cordova St. East, Vancouver, BC, Canada V6A 4A3
ACME is an ISO 9001:2000 certified laboratory.
The following describes sample preparation and analytical procedures for the 2005 to 2007
drilling programs.
13.2.1 Sample Preparation
Sawed core samples are shipped by truck to ACME’s sample preparation facility in Vancouver,
BC. There is a system of forms that detail each shipment and under whose charge it was
between the project and the lab (chain of custody).
The sample preparation protocol is as follows:
1. Receive samples, lay out on benches, check sample state, order and identification.
2. Leave in original plastic bags which are opened and place on carts and dry at 60°C until
the sample is dry in drying rooms.
3. Crush each sample in jaw crusher to >70% passing -10 mesh. Crusher is cleaned with
brush and compressed air between each sample.
4. Samples are homogenized and split to obtain 250g sample using riffle splitter.
5. Pulverize 250g split to 95% passing -150 mesh using mild steel ring and puck mill. The
mill is cleaned with granite wash after high-grade samples, between changes in rock
colour and/or at the end of each file of samples.
6. Bag the reject with original sample stored at ACME.
Analysis for zinc, lead and silver is done using a hot Aqua Regia digestion with an ICP-ES
finish (ACME method: Group 7AX), and is as follows:
1. Add 1g (+/-0.002g) of sample pulp to glass test tube
2. Add 30ml of Aqua Regia (2:2:2 mixture of HCl, HNO3 and H2O) digested for 1 hour in
hot water bath (>95°C).
3. Cool sample for 3 hours and then make up volume to 100ml with dilute (5%) HCl.
4. Solutions aspirated into Spectro Ciros Vision ICP atomic-emission spectrometer.
QC sample insertion
Mantle sampling staff inserted Standards and Blanks at a rate of one in thirty samples. Core
duplicate samples, obtained from sawing ¼ core splits, are taken at a rate of one in thirty
samples. During the period from 2005 through to the beginning of 2007, Mantle had pulp
duplicate samples taken from all “significant mineralized” intervals and reanalyzed at Global
Discovery labs (Method: Group 4) in Vancouver, BC. Global Discovery is operated by Teck
Cominco Limited.
Standards and Blanks were inserted randomly by pre-assigned tag numbers. Blank material
during the 2005 drilling program was obtained from a local outcrop which contained no visible
- 55 -
signs of mineralization. All blank material used in the 2006 and 2007 drilling programs was
purchased from WCM Minerals, Burnaby BC, Canada.
Chain of Custody
In preparation for shipment of the samples to the lab, the sample bags are then laid out in order
and placed into rice bags, five to a bag. The labs address and phone number, the expeditors
address and phone number, sequence of samples and the bag number are recorded on the
outside of the rice bag. The bags are sealed with a plastic “zap strap” and a security tag. The
contents of each bag and the security tag number are recorded on a spread sheet. The lab
submittal form is filled out recording the samples to be submitted and the desired analysis
packages.
Shipments are backhauled via Wrights Food Services transport trucks to the project’s expeditor
located at the Northern Thunderbird Air hanger in Mackenzie. Prior to departure from camp the
delivery truck driver signs off that they have received the shipment and upon arrival in
Mackenzie, the expeditor signs off that they have received the samples. The samples are then
placed upon a wooden pallet and shrink wrapped and held within the secure NT Hanger in
Mackenzie.
The samples are then shipped via truck using transport contractors P.G Lite, from Mackenzie to
Van Kam Shipping in Prince George. The tracking number for the shipment is given to Mantle
Akie site personnel. Van Kam transports the samples, via transport truck, to Acme Labs in
Vancouver. Once again the tracking number is recorded and given to Akie site personnel. Upon
delivery of the samples at Acme labs, notification is given to Mantle personnel at the Akie site.
All procedures are being carefully attended and meet or exceed industry standards for
collection, handling, and transport of drill core samples.
13.2.2 Control Sample Performance
Standard Reference Material (SRM) Performance
Mantle purchased standard reference material for the project from WCM Minerals located in
Burnaby BC, Canada. The six certified standards for zinc, lead and silver are named PB109,
PB110, PB111, PB112, PB118 and PB123. The performance of standard reference material
(SRM or standards) is evaluated using the criterion that ninety percent of the results must fall
within ±10% of the accepted value for the assay process to be in control. Results are presented
using statistical process control charts (control charts for short). In the chart the “accepted” or
average value appears as a blue horizontal line. Control limits at ±10% of the accepted value
appear as red lines above and below the line showing the accepted value. The values of assay
results for the standard appear on the chart as dark blue diamonds.
Results for all standards fall within control limits more frequently than the prescribed rate
(Figures 15 to 20). There is no indication of systematic assaying problems in the copper values.
Sample Blank Performance
Control results exceeded the control limit for the blank material assays less than five percent of
the time (Figure 21). The local Blank material used in the 2005 program shows erratic results
due to the use of non-sterile material.
- 56 -
Figure 15. STD PB109
- 57 -
Figure 16. STD PB 110
- 58 -
Figure 17. STD PB 111
- 59 -
Figure 18. STD PB 112
- 60 -
Figure 19. STD PB 118
- 61 -
Figure 20. STD PB 123
- 62 -
Figure 21. Sample blank performance
- 63 -
Figure 22. Core duplicate sample performance
- 64 -
Figure 23. Pulp duplicate sample performance – Zn
Coarse (core) Duplicate Sample Performance
The results of the core duplicates (Figure 22) show a relatively erratic distribution of variability
that is reduced as the grade of samples increases. The average relative difference for zinc is
8%, lead 0% and silver 6% which is considered acceptable for sample duplicates of this type.
Pulp Duplicate Sample Performance
Figure 23 shows a comparison between zinc analyses conducted at ACME verses Global.
Overall, the relative difference between the two labs is only 1%. However, samples which
exceed a grade of approximately 8% zinc show a relative difference of about +5% at ACME.
This difference is attributed to differences in the analytical protocols used at the two labs. Both
ACME and Global employ a hot Aqua Regia digestion but different analytical techniques,
Inductively Coupled Plasma (ICP)-Emission Spectroscopy (ES) by the former and Atomic
Absorption (AA) by the latter.
- 65 -
Similar differences are seen in the lead pulp duplicates in Figure 24. The overall relative
difference of lead assays is 3%.
Figure 24. Pulp duplicate sample performance - Pb
13.3 Conclusions
Results from SRM indicate the zinc, lead and silver assay process is under sufficient control to
produce reliable sample assay data for resource estimation. Blank results indicate no
contamination in the assay process. Coarse reject results confirm that the sample preparation
protocol is adequate to produce the necessary reliability for sample results. The pulp duplicate
results indicate some discrepancy in the higher-grade samples which is attributed to differences
in the assay protocols used between ACME and the umpire lab.
- 66 -
The Akie deposit sampling and assaying program is producing sample information that meets
industry standards for zinc, lead and silver accuracy and reliability. The assay results are
sufficiently accurate and precise for use in resource estimation.
14.0 DATA VERIFICATION
The primary source of data for the Akie Mineral Claims has been the historical work reported
by previous operators, which includes geochemical surveys, geophysical surveys and diamond
drilling. Examination of the analytical results presented in publicly available assessment reports
and in a previous compilation report (Baxter, 1996c) suggests that quality assurance was
performed to the best practice standards of the day.
A sample of thin bedded massive sulphide was collected by from the Cardiac Creek showing on
August 26, 2005 by D.G. MacIntyre and was submitted to Acme Analytical Laboratories in
Vancouver for analysis. This sample assayed 23.82% Zn, 4.6% Pb and 29 grams per tonne Ag.
A copy of the analytical certificate is contained in a previous NI43-101 technical report
(MacIntyre, 2005). These values are similar to those reported elsewhere for the Cardiac Creek
showing (e.g. Baxter 1995, 1996) and confirm the high grade nature of the massive sulphide
mineralization.
As part of the data validation, seven drill holes, representing over 10% of the total drilling
database, were randomly selected for manual validation back to the original data source. This
included collar locations, down hole surveys, lithology codes, bulk density measurements and
assay results.
Three errors were identified in the down hole survey data where differences in the azimuth or
dip values were noted in the first decimal level of accuracy. This is considered insignificant
with respect to drill hole locations.
During the site visit, the qualified person (Mr. Sim) visually correlated the sphalerite and galena
contents in drill core with the reported assay grades for a random selection of drill holes. There
were no discrepancies noted.
The sampling protocols used in the development of the Mantle sample database follow accepted
industry standards and have been verified through an extensive QAQC program.
A portion of the database is derived from drilling data generated by Inmet during the period
from 1994 through 1996. Although this includes a total of 29 holes in the database, only nine
of these holes are located in the vicinity of the resource model. The collar locations of these
holes have been verified in the field by Mantle site personnel. The drill core from these holes is
stored on the Akie property and the mineralized intervals are stored in a warehouse facility in
Richmond BC. There are no assay certificates available for the Inmet data however, the
mineralized intervals from Inmet drill holes were visually reviewed (and validated) by Robert
Sim in 1996 while an employee at Inmet’s Vancouver office. Drilling activities conducted by
Inmet in 1994-96 were conducted in a professional manner and the data produced can be
considered valid and reliable.
The results of the data verification indicate that the database is sound and reliable for the
purposes of resource estimation.
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15.0 ADJACENT PROPERTIES
As mentioned previously, the Akie property lies within a belt of SEDEX showings collectively
known as the Gataga District. North of the property is the Fluke showing and to the south the
Elf. Mineral tenures covering these showings are shown on Figure 3. These showings are
believed to be at the same stratigraphic level as the Cardiac Creek showing.
15.1 Fluke
The Fluke property covers a northwest-trending synclinal keel of Gunsteel strata that is
bounded by Silurian siltstone to southwest and Middle Devonian limestone to the northeast
(Roberts, 1978). The Silurian rocks have been thrust northeastward over the Gunsteel syncline.
The property was staked by Cyprus Anvil Mining in 1978 to cover a small showing of laminarbanded pyrite with galena-sphalerite rich bands that is exposed in a small northeast flowing
tributary of the Akie River. Several nodular barite beds also crop out on the property. At
surface, the mineralized interval is about 1 metre thick and dips to the west. The host rocks are
intensely deformed carbonaceous cherty argillites and siliceous shales of the Late Devonian
Gunsteel formation. Assays of up to 15 percent combined lead-zinc and 35 grams per tonne
silver have been reported. Cyprus Anvil drilled the property in 1980, 1981 and 1982. Only one
drill hole intersected sulphide mineralization at approximately 200 metres down-dip from the
surface showing (Paradis et. al., 1998).
15.2 Elf
The Elf property was staked by Cyprus Anvil Mining Corporation in 1978 to cover an area of
moderately anomalous stream sediment geochemistry and the occurrence of a boulder of white
barite containing high grade galena and sphalerite in Elf creek (Roberts, 1979). Subsequent soil
sampling resulted in discovery of an outcrop of bedded barite with high grade bands of galena
and sphalerite on the heavily timbered south facing slope north of Elf Creek. The mineralized
zone has been exposed on surface by trenching and is up to 4 metres thick. A sulphide rich
sample from this zone assayed 14.1 percent zinc, 25 percent lead and 106 grams per tonne silver
(MacIntyre, 1998). Host rocks are carbonaceous cherty argillites and siliceous shales of the
Gunsteel formation. The property was drill tested in 1979 and 1980. Drill holes intersected
laminar-banded pyrite at depth; barite-sulphide mineralization similar to the surface showings
was not intersected. The best drill intersection contains 13.8 percent combined Pb+Zn with 27
grams per tonne Ag over 11 metres (Paradis et al., 1998).
Drilling and surface mapping suggests the Elf mineralization is contained within a steeply
dipping, overturned fold limb that is overthrust to the west by Silurian dolomitic siltstones.
Intense folding and structural imbrication of the Gunsteel host rocks has made defining the
geometry of the mineralized interval difficult.
16.0 MINERAL PROCESSING AND METALLURGICAL TESTING
In October, 1995, Rainer Lehne, of Sachtleben Bergbau GMGH & Co. visited the Akie
property on behalf of Inmet Mining Corporation and collected several samples of massive
sulfides from drill core and the Cardiac Creek discovery showing, shales, baritic shale, barite,
footwall breccia and calcareous siltstone for petrographic examinations. Lehne (1995)
concluded that the fine grained nature of the mineralization and the intergrown association of
- 68 -
pyrite and sphalerite will result in a zinc concentrate with a high iron content as a result of high
pyrite in the con.
Mantle has submitted samples of core from holes completed in 2005 (135.67 kg) and 20006
(165.00 kg) to a major metallurgical testing facility to investigate the flotation, grinding and
heavy liquid characteristics of the Cardiac Creek mineralization. This work was in progress and
at the time this report was prepared and results were not available.
17.0 MINERAL RESOURCE AND MINERAL RESERVE ESTIMATES
17.1 Introduction
The mineral resource estimate was prepared under the direction of Robert Sim, P.Geo with the
assistance of Bruce Davis, FAusIMM. Mr. Sim is the independent Qualified Person within the
meaning of NI 43-101 for the purposes of mineral resource estimates contained in this report.
Estimations are made from 3-dimensional block models based on geostatistical applications
using commercial mine planning software (MineSight® v4.02). The project limits area based
in the UTM coordinate system using a nominal block size of 5x10x5m, with the longer blocks
parallel to the strike of the deposit at Az315º. The primary orientation of the drilling is at
Az50º, designed to intersect the steeply dipping deposit (-70ºSW) from the hangingwall side.
There are several deep holes drilled from the footwall side of the deposit.
The resource estimate has been generated from drill hole sample assay results and the
interpretation of a geologic model which relates to the spatial distribution of zinc, lead and
silver. Interpolation characteristics have been defined based on the geology, drill hole spacing
and geostatistical analysis of the data. The resources have been classified by their proximity to
the sample locations and are reported, as required by NI43-101, according to the CIM standards
on Mineral Resources and Reserves.
Figure 25. Isometric view of Minzone domain – example 1
- 69 -
Figure 26. Isometric view of Minzone domain – example 2
This report includes estimates for mineral resources. There are no mineral reserves prepared or
reported.
17.2 Geologic Model, Domains and Coding
The Akie deposit exhibits properties typical of a sedimentary exhalative (Sedex) deposit,
common in this area of BC. The deposit occurs as a planar sheet-like zone of semi-massive to
massive sulphides comprised of varying amounts of pyrite, sphalerite and galena (+/- barite)
which has been traced over strike length of 6.5km and to a depth of 1300 metres below surface.
The mineralized zone ranges from less than 1m, to as much as 40 metres thickness and averages
about 20 metres (true) thickness in the area of potential economic interest.
The mineralized zone (Minzone) has been interpreted from drill hole assay sample data. Points
representing the top and bottom of mineralization above a grade of 1%Zn have been interpreted
in all drill holes. The threshold grade of 1%Zn is derived from visual observations of the
“natural” increase in zinc grade in the drill holes and is supported by a distinct inflection of the
distribution of zinc sample data on a cumulative probability plot. Several additional points
were added to provide projections of the mineralization into areas currently lacking drilling (i.e.
to project the Minzone through to surface). The resulting points are then triangulated into 3
dimensional surfaces which are finally joined to form a 3D wireframe solid domain. Attempts
were made to retain the planar nature of the Minzone during this process and, as a result, some
mineralized intervals in drill holes have been excluded from the domain model. These
somewhat anomalous mineralized zones are interpreted to be localized fault splays or veins
which do not represent significant potential resources. Examples of the Minzone domain are
shown in Figures 25 and 26.
- 70 -
Other than some thin surficial oxidation where sulphides occur at surface, there are no
indications of significant oxidation of the resource. There is relatively little overburden in the
area of the mineral resource and, as a result, there have been no adjustments made to the model
to account for this.
17.3 Available Data
There are a total of 56 drill holes on the Property with a total core length of 26,957 metres. Of
these, 48 holes are within the proximity of the resource model. (The remaining 8 drill holes test
the zone over a total strike length of almost 7 kilometres).
A combination of access challenges in this rugged terrain combined with often severe drill hole
deviation have resulted in a somewhat variable distribution of drill holes into the Akie deposit.
The spacing of pierce points into the Minzone is highly variable ranging from 40 metres to over
500 metres and average approximately 100 metres.
Select intervals within drill holes have been sampled and analyzed based on visual observations
of the presence of sulphide mineralization. A total of 3,598 metres of core, in 3,653 individual
samples, have been analyzed for zinc, lead and silver (often as part of 26 element package).
Sample intervals, which range from 0.1m to 3.05m and average 1m in length, have been
selected so they do not straddle a geologic boundary and have also been selected to represent
intervals of similar sulphide type or content.
The drill hole sample intervals have been “speared” with the Minzone domain – coding
intervals which occur within the domain shell. The basic statistical properties of the samples
within the MinZone domain are listed in Table 5.
Table 5. Summary of Basic Statistics of Samples Inside Minzone Domain
Element
#smp
Min
Max
Mean
Std.Dev.
Zinc (%)
1,380
0
36.73
5.29
5.97
Lead (%)
1,380
0
9.13
1.04
1.30
Silver (gpt)
1,380
0
66.0
9.7
9.5
(original sample data weighted by sample length)
17.4 Bulk Density Data
There are a total of 3,212 sample intervals in the drill hole database have values for bulk density
conducted at ACME using the weight in air verses water method (SG=weight in air/weight in
water). This represents approximately 88% of the total sample intervals sampled for zinc in the
database and 92.5% of the intervals contained within the Minzone domain. Values range from
a minimum of 1.53t/m3 to a maximum of 4.46t/m3 with a mean of 2.88t/m3. Limited to
samples within the Minzone domain, the mean SG increases to 3.10t/m3
Comparisons between zinc grade and SG in samples within the Minzone domain show a
correlation coefficient of 0.71. Intervals which have been analyzed for zinc but have missing
(measured) bulk densities have been assigned SG values using the regression formula:
SG=2.865 + (Zn% * 0.045)
- 71 -
17.5 Compositing
Compositing of drill hole samples is carried out in order to standardize the database for further
statistical evaluation. This step eliminates any effect related to the sample length which may
exist in the data.
Drill hole composites are weighted by both the length and bulk density of the original sample
interval and have been generated “down-the-hole” meaning that composites begin at the top of
each hole and are generated at 1 metre intervals down the length of the hole. The contacts of
the Minzone domain were honoured during compositing of drill holes. Several holes were
randomly selected and the composited values were checked for accuracy. No errors were
found.
Bulk density weighting of composite samples increases the overall zinc grade by 0.1% (+2%
relative) when compared to the mean grade of length-only weighted composite data.
17.6 Exploratory Data Analysis
Exploratory data analysis (“EDA”) involves the statistical summarization of the database in
order to quantify the characteristics of the data. One of the main purposes of this exercise is to
determine if there is evidence of spatial distinctions in grade which may require the separation
and isolation of domains during interpolation. The application of separate domains prevents
unwanted mixing of data during interpolation and the resulting grade model will better reflect
the unique properties of the deposit. However, applying domain boundaries in areas where the
data is not statistically unique may impose a bias in the distribution of grades in the model.
A domain boundary, which segregates the data during interpolation, is typically applied if the
average grade in one domain is significantly different from that of another domain. A boundary
may also be applied where there is evidence that there is a significant change in the grade
distribution across the contact.
17.6.1 Basic statistics by Domain
The basic statistics for the distribution of zinc, lead and silver inside and surrounding the
Minzone domain are listed in Table 6 and 7. As stated previously, samples are generally
selected based on the visual observations of sulphide mineralization. As a result, much of the
area surrounding the Minzone domain has not been sampled and analyzed.
Table 6. Summary of Basic Statistics of Composited Samples Inside Minzone Domain
Element
#smp
Min
Max
Mean
Std.Dev.
Zinc (%)
1,307
0
34.41
5.34
5.50
Lead (%)
1,307
0
7.97
1.04
1.23
Silver (gpt)
1,307
0
65.70
9.7
8.8
(1m composited sample data weighted by sample length)
The results above show that, although there are several rare mineralized intervals outside of the
Minzone domain, the mean grades indicate a significant difference between the zones.
- 72 -
Table 7. Summary of Basic Statistics of Composited Samples Outside of Minzone Domain
Element
#smp
Min
Max
Mean
Std.Dev.
Zinc (%)
2,470
0
6.37
0.18
0.40
Lead (%)
2,470
0
1.25
0.03
0.07
Silver (gpt)
2,470
0
22.20
1.6
1.9
(1m composited sample data weighted by sample length)
17.6.2 Contact Profiles
The nature of grade trends between two domains is evaluated using the contact profile which
graphically displays the average grades at increasing distances from the contact boundary.
Contact profiles which show a marked difference in grade across a domain boundary, are an
indication that the two data sets should be isolated during interpolation. Conversely, if there is
a more gradual change in grade across a contact, the introduction of a “hard” boundary
(i.e. segregation during interpolation) may result in much different trends in the grade model –
in this case the change in grade between domains in the model is often more abrupt than the
trends seen in the raw data. Finally, a flat contact profile indicates no grade changes across the
boundary. In the case of a flat profile, “hard” or “soft” domain boundaries will produce similar
results in the model.
A series of contact profiles were generated to evaluate the nature of zinc, lead and silver grades
through across the Minzone domain boundary. As expected, abrupt changes in all grades occur
across this contact.
17.6.3 Conclusions and Modeling Implications
The results of the EDA indicate that the zinc, lead and silver grades within the Minzone domain
are significantly different than those in the surrounding area and that the Minzone domain
should be treated as a distinct (hard) domain during block grade estimations.
Due to the low overall grades in the area surrounding the Minzone domain, grade estimates
have not been conducted on this portion of the model.
17.7 Evaluation of Outlier Grades
Histograms and probability plots were reviewed in order to identify the presence of anomalous
outlier grades for zinc, lead and silver in the composited (1m) drilling database. Following a
review of the physical location of potentially erratic samples in relation to the surrounding
sample data, it was decided that these would be controlled during block grade interpolations
using an outlier limitation. An outlier limitation controls the distance of influence of samples
above a defined grade threshold – in this case, all samples are limited to a maximum distance of
influence of 20 metres during block grade interpolation. The grade thresholds for zinc, lead and
silver are listed in Table 8.
- 73 -
Table 8. Outlier Grade Analysis Inside Minzone Domain
Element
O/L limit
Samples
affected (#)
Metal lost (%)
Zinc (%)
22
18
-2.5
Lead (%)
5
24
-3.4
Silver (gpt)
35
27
-1.6
-
1m composited drill hole data.
Samples >O/L limited to max. distance of 20m.
Table 9. Variogram Parameters – Zinc
Zone
Nugget
0.250
Minzone
S1
Range
(m)
0.750
Spherical model
AZ
Dip
140
225
-70
54
135
0
13
225
20
(Correlograms conducted on 1m DH composite data.)
Table 10. Variogram Parameters – Lead
Zone
Nugget
0.150
Minzone
S1
Range
(m)
0.850
Spherical model
AZ
Dip
140
225
-70
54
135
0
12
225
20
(Correlograms conducted on 1m DH composite data.)
Table 11. Variogram Parameters – Silver
Zone
Nugget
0.150
Minzone
S1
Range
(m)
0.850
Spherical model
AZ
Dip
160
225
-70
57
135
0
15
225
20
(Correlograms conducted on 1m DH composite data.)
17.8 Variography
The degree of spatial variability in a mineral deposit depends on both the distance and direction
between points of comparison. Typically, the variability between samples increases as the
distance between samples also increases. If the degree of variability is related to the direction
of comparison, then the deposit is said to exhibit anisotropic tendencies which can be
summarized with the search ellipse. The semi-variogram is a common function used to
measure the spatial variability within a deposit.
- 74 -
The components of the variogram include the nugget, the sill and the range. Often samples
compared over very short distances (even samples compared from the same location) show
some degree of variability. As a result, the curve of the variogram often begins at some point
on the y-axis above the origin – this point is called the “nugget”. The nugget is a measure of
not only the natural variability of the data over very short distances but also a measure of the
variability which can be introduced due to errors during sample collection, preparation and
assaying.
The amount of variability between samples typically increases as the distance between the
samples becomes greater. Eventually, the degree of variability between samples reaches a
constant, maximum value. This is called the “sill” and the distance between samples at which
this occurs is referred to as the “range”.
The spatial evaluation of the data in this report has been conducted using a correlogram rather
than the traditional variogram. The correlogram is normalized to the variance of the data and is
less sensitive to outlier values, generally giving better results.
Variograms were generated using the commercial software package Sage 2001© developed by
Isaacs & Co. Multidirectional variograms were generated for zinc, lead and silver in the
Minzone domain with the results summarized in the tables below (Tables 9-11).
17.9 Model Setup and Limits
A block model was initialized in MineSight® and the dimensions are defined in Table 12. The
selection of a nominal block size measuring 5x10x5m is considered appropriate with respect to
the current drill hole spacing as well as the selective mining unit (“SMU”) size typical of an
operation of this type and scale. The block model is horizontally rotated so that the Y-axis is
parallel to the strike of the Minzone at 315 degrees. The block model limits are shown in
Figures 25 and 26.
Table 12. Block Model Limits
Direction
Minimum
Maximum
Block size
(m)
# Blocks
X (Az 45º)
0
600
5
120
Y (Az 315º)
0
2400
10
240
500
1600
5
220
Z (elev)
Blocks in the model have been assigned a code number if they are wholly or partially within the
Minzone domain. Block partial values (percentage of block inside Minzone domain) are also
determined – this is used as a weighting item when determining resources.
17.10 Interpolation Parameters
The block model grades for zinc, lead and silver have been estimated using Ordinary Kriging
(OK). The results of the OK estimation were compared with the Hermitian (Herco) polynomial
change of support model (also referred to as the Discrete Gaussian correction). This method is
described in more detail in Section 17.11.
The Akie OK model has been generated with a relatively limited number samples in order to
match the change of support or Herco grade distribution. This approach reduces the amount of
smoothing (averaging) in the model and, while there may be some uncertainty on a localized
- 75 -
scale, this approach produces reliable estimations of the recoverable grade and tonnage for the
overall deposit.
Estimates for bulk density have been made in the block model using the inverse distance
weighted (ID to the power of 2) interpolation method. The parameters used in SG estimates are
also listed in Table 13.
All grade estimations use length weighted composite drill hole sample data.
During grade estimations, the search orientations have been designed to follow a mineralization
“trend” surface created from the average between the hangingwall and footwall surfaces of the
Minzone domain. A temporary elevation item is assigned to all composited drill hole samples
and model blocks which is “relative” to the elevation from the trend surface. Using the relative
elevations during grade estimations ensures that the grades in the model replicate the minor
undulations interpreted in the Minzone domain.
The interpolation parameters for zinc, lead and silver are summarized in the table below.
Table 13. Interpolation Parameters
Element
Search Ellipse(1) Range
(m)
# Composites (2)
Other
X
Y
Z
Min/block
Max/block
Max/hole
Zinc
250
250
70
8
21
7
1 DH per quadrant
Lead
250
250
70
8
21
7
1 DH per quadrant
Silver
250
250
70
8
21
7
1 DH per quadrant
SG (3)
250
250
70
3
15
5
1 DH per quadrant
(1) Ellipse orientation parallel to Minzone at Az315º, Dip-70ºSW.
(2) 1m composite length.
(3) SG estimated using ID2 method.
17.11 Validation
The results of the modeling process were validated through several methods. These include a
thorough visual review of the model grades in relation to the underlying drill hole sample
grades, comparisons with the change of support model, comparisons with other estimation
methods and grade distribution comparisons using swath plots.
17.11.1 Visual Inspection
Detailed visual inspection of the block model has been conducted in both section and plan to
ensure the desired results following interpolation. This includes confirmation of the proper
coding of blocks within the Minzone domain. The zinc, lead and silver grades in the model
appear to be a valid representation of the underlying drill hoe sample data.
- 76 -
Figure 27. Change of support plot - Zinc
17.11.2 Model Checks for Change of Support
The relative degree of smoothing in the block model estimates were evaluated using the
Discrete Gaussian of Hermitian Polynomial Change of Support method (described by Journel
and Huijbregts, Mining Geostatistics, 1978). With this method, the distribution of the
hypothetical block grades can be directly compared to the estimated (OK) model through the
use of pseudo-grade/tonnage curves. Adjustments are made to the block model interpolation
parameters until an acceptable match is made with the Herco distribution. In general, the
estimated model should be slightly higher in tonnage and slightly lower in grade when
compared to the Herco distribution at the projected cut-off grade. These differences account for
selectivity and other potential ore-handling issues which commonly occur during mining.
The Herco (Hermitian correction) distribution is derived from the declustered composite grades
which have been adjusted to account for the change in support as one goes from smaller drill
hole composite samples to the large blocks in the model. The transformation results in a less
skewed distribution but with the same mean as the original declustered samples.
Due to the fact that the Akie is primarily a zinc deposit about which cut-off decisions will be
based, the Herco analysis is restricted to the distribution of zinc in the model. The Herco plot is
shown in Figure 27.
17.11.3 Comparison of Interpolation Methods
For comparison purposes, additional models for zinc, lead and silver were generated using both
the inverse distance weighted (“IDW”) and nearest neighbour (“NN”) interpolation methods
(the NN model was made using data composited to 5m intervals). Comparisons are made
between these models on grade/tonnage curves. The grade/tonnage curves for zinc, lead and
silver are shown in Figures 28 through 30. There is good correlation between all models
throughout the range of cut-off grades. The OK model is slightly lower grade than the ID
estimates and the difference with the NN model is expected for a project at this relatively early
- 77 -
stage of drilling evaluation. Reproduction of the model using different methods tends to
increase the confidence in the overall resource.
Figure 28. Grade-tonnage curve - Zinc
Figure 29. Grade-tonnage curve – Lead
- 78 -
Figure 30. Grade-tonnage curve - Silver
17.11.4 Swath Plots (Drift Analysis)
A swath plot is a graphical display of the grade distribution derived from a series of bands, or
swaths, generated in several directions through the deposit. Grade variations from the OK
model are compared using the swath plot to the distribution derived from the declustered (NN)
grade model.
On a local scale, the NN model does not provide reliable estimations of grade but, on a much
large scale, it represents an unbiased estimation of the grade distribution based on the
underlying data. Therefore, if the OK model is unbiased, the grade trends may show local
fluctuations on a swath plot but the overall trend should be similar to the NN distribution of
grade.
Swath plots have been generated in three orthogonal directions and examples in the E-W slices
for the distribution zinc, lead and silver are shown in Figures 31 through 33.
There is good correspondence between the models in most areas. The degree of smoothing in
the OK model is evident in the peaks and valleys shown in the swath plots. Deviations tend to
occur for two reasons. First, reduced tonnages near the edges of the deposit tend to accentuate
the differences in grade between models. Second, differences in grade become more apparent
in the lower-grade areas – these typically are the flanks of the deposit where the density of
drilling decreases. Note that the potentially economic portion of the deposit (i.e. >4%Zn cut-off
grade) occurs between 388200E and 389000E – the swath plots show very good correlation in
this area.
- 79 -
Figure 31. Swath plot - Zinc
Figure 32. Swath plot - Lead
- 80 -
Figure 33. Swath plot - Silver
17.12 Resource Classification
The mineral resources at the Akie deposit have been classified in accordance with the CIM
definition standards for mineral resources and mineral reserves (CIM, 2005). The classification
parameters, listed below, are defined in relation to the distance to sample data and the quantity
of samples used in the estimation.
Based on the current density of drilling on the deposit, there are no resources that meet the
criteria required for measured or indicated resources. The definition of mineral resources in the
inferred category is listed below.
Inferred Mineral Resources – Blocks in the Minzone domain within a maximum distance of
125 metres from a drill hole.
- 81 -
Figure 34. Distribution of inferred mineral resources above base case cut-off grade of 5% Zn.
17.13 Mineral Resources
The Akie deposit mineral resources are summarized at a series of zinc cut-off grades for
comparison purposes in Table 14. Highlighted in the tables is the “base case” cut-off grade of
5.0% Zn which is considered reasonable based on assumptions derived from operations with
similar characteristics, scale and location.
Table 14. Inferred Mineral Resource
Cut-off Grade
(Zn%)
ktonnes
Zn (%)
Pb (%)
Ag (gpt)
2
50,874
5.28
1.00
9.6
3
37,683
6.25
1.22
11.0
4
30,595
6.89
1.36
12.0
5
23,595
7.60
1.50
13.0
6
17,051
8.41
1.68
14.2
7
11,841
9.26
1.86
15.4
(3)
(4)
“Base case” cut-off grade of 5.0%Zn highlighted in table.
Resources are not mineral reserves as the economic viability has not been
demonstrated.
- 82 -
It is important to realize that the tables below list mineral resources – these are not mineral
reserves as the economic viability has not been demonstrated.
There are no known factors related to environmental, permitting, legal, title, taxation, socioeconomic, marketing or political issues which could materially affect the mineral resource.
The distribution of inferred mineral resources above the base case cut-off grade of 5% zinc is
shown in Figure 34. Note that the resource, at a cut-off limit, occurs as a relatively continuous
zone which is favourable with respect to selectivity and other factors when considering mining
options. As a result, the stated resource is considered to exhibit a reasonable degree of
economic viability.
18.0 OTHER RELEVANT DATA AND INFORMATION
The writers have reviewed the sources of information cited under References including drill
hole logs, cross-sections and property maps at various scales produced by the different
operators on the Akie property. Some of the reports reviewed are publicly available as
assessment reports through the B.C. Ministry of Energy and Mines, others are internal reports
done by or for the property operator. The writers are not aware of, or were not presented with,
any additional sources of information that might significantly change the conclusions presented
in this technical report. At the time of writing final summary reports for the 2007 drilling
program were not available for review.
Mantle is currently engaged in advanced discussions with the Kwadacha First Nation and the
Tsay Keh Dene, each with a Traditional Territory that overlap and collectively encompass the
Akie property, regarding a Memorandum of Understanding (MoU) which will define the
relationship between the three parties during the exploration phase of project advancement. It is
expected that this document will be ratified in the near future.
In mid-March, 2008, Mantle commenced construction of a 8.7 km long extension to the existing
Akie Main Line logging road which terminates approximately 7 km southwest of the Cardiac
Creek exploration area. The new road and two shorter access trails are expected to be fully
usable by September, 2008, and will significantly reduce the need helicopter support for
diamond drilling and other exploration activities. This will result in lower costs, an extended
exploration season, increased safety for operating personnel, and will provide access and
logistical support for future underground exploration operations.
19.0 INTERPRETATION AND CONCLUSIONS
The Akie property contains a zinc-lead-silver bearing deposit which exhibits features indicating
it is characterized as a Sedex deposit, similar to other proximal deposits in this area of BC and
the Yukon. Mineralization occurs within a sheet-like zone that dips steeply to the SW and has
been intersected in drilling over a strike length of almost 7 kilometres.
Analysis of the drill sample database shows that it is sound and reliable for the purposes of
resource estimation. The resource model has been developed in accordance with accepted
industry standards resulting in a mineral resource defined within the inferred category.
The potentially economic portion of the deposit occurs over a strike length of 1300m, extends
to 800 metres below surface and averages about 20 metres in thickness. The deposit currently
remains “open” (to some degree) in all directions however, the potential to add significant
additional tonnage to the current zone of resources is probably limited based on current data.
- 83 -
Metallurgical studies to date, although very preliminary in nature, indicate that the deposit is
amenable to standard extraction methods used at similar deposits.
The objective of this report was to produce a mineral resource estimation for the Akie property
and to provide recommendations with respect to the next stage of advancement of the project.
The inferred mineral resource, at a 5%Zn cut-off grade, is 23.6Mtonnes at 7.6%Zn, 1.5%Pb and
13gptAg.
20.0 RECOMMENDATIONS
Drilling has been notoriously difficult at Akie due to a combination of access difficulties with
the steep terrain and the unpredictable deviations often encountered with drill holes. It is
recommended that a total of 14 holes are required to infill the current base case resource (>5%
Zn) to approximately 100 metre spaced intervals. This information will provide sufficient
information regarding the continuity of the zone to justify the next (anticipated) stage of the
project – an underground program which will allow for access to drill the deposit off to a
combination of measured and indicated classification status. The infill drilling program is
represented in Figure 35 and will require approximately 7000 metres of drilling to complete.
Metallurgical studies, involving grinding/flotation/cleaning test work on a series of
representative samples, is also recommended. In addition, ongoing environmental investigations
are required in order to obtain information necessary for permitting for the anticipated
underground exploration program.
Figure 35. Base case resource estimate showing proposed in-fill drill holes.
Estimated costs for the recommended program are summarized in Table 15. Note that the high
projected costs for the proposed drilling program ($450/metre) are based on the actual costs
incurred during recent drilling programs in 2005, 2006 and 2007.
- 84 -
Table 15. Estimated Cost of the Recommended Program
Diamond drilling (7000 m @ $450/m)
$3,150,000
Helicopter support (7000m @$145/m)
$1,015,000
Camp costs (R&B @ $200/md for 90 d)
$468,000
Camp management (incl. fuel, FA/safety etc)
$70,000
Geological support (geologists, geotechnicians)
$125,000
Assays (560 samples @$35/sample)
$20,000
Rentals (radios/communications, trucks, misc. equip.)
$45,000
Environmental( biotic, surf. geol., rock geochem., arch.etc.)
$532,000
Metallurgy(as above)
$200,000
- 85 -
Subtotal
$5,625,000
Contingency @10%
$562,500
TOTAL
$6,187,500
21.0 REFERENCES
Baxter, P., (1995): Soil Geochemical, Geophysical and Diamond Drilling Assessment Report,
Akie Claims, NTS 94F7W B.C. Ministry of Energy and Mines Assessment Report No.
23870, 1311 pages.
Baxter, P., (1996): Diamond Drilling Assessment Report, Akie Claims, NTS 94F7W; B.C.
Ministry of Energy and Mines Assessment Report No. 24323, 41 pages.
Baxter, P., (1996a): Soil Geochemical and Diamond Drilling AssessmentArea
Report,
Claims,
of PhaseAkie
1
Drilling
NTS 94F7W; B.C. Ministry of Energy and Mines Assessment Report
No. 24439, 173
pages.
Baxter, P., (1996b): Gataga Project, Akie Claims, 1996 Soil Geochemical and Diamond
Drilling Assessment Report, NTS 94F7W; B.C. Ministry of Energy and Mines
Assessment Report No. 24703, 157 pages.
Baxter, P., (1996c): Summary and Compilation Report, Gataga Project, Akie Claims; Inmet
Mining Corporation, internal company report, 35Cardiac
pages.Creek
Showing
Baxter, P., Kapusta, J., Morrison, I., and Wells, G. (1996): Cardiac Creek Zn-Pb-Ag deposit,
Akie property (abstract); Cordillera Roundup, 1996, British Columbia-Yukon Chamber of
Mines, Abstracts, pages 1-2.
Campbell, R.B., (1967): Reconnaissance geology of Glenlyon map area, Yukon Territory;
Geological Survey of Canada, Memoir 352.
Carne, R.C. (1978): Driftpile lead-zinc district; B.C. Ministry of Energy, Mines and Petroleum
Resources, Assessment Report 6666.
Cecile, M.P. and Norford, B.S., (1979): Basin to platform transition, Lower Paleozoic strata of
Ware and Trutch map areas, northeastern British Columbia; Current Research, Part A,
Geological Survey of Canada, Paper 79-1A, pages 219-226.
Davies, E.J.L., (1966): Ordovician and Silurian of the northern Rocky Mountains between
Peace and Muskwa rivers, British Columbia, unpublished Ph.D. thesis; University of
Alberta.
Davis, B. M., (1997): Some Methods of Producing Interval Estimates for Global and Local
Resources, SME Preprint 97-5, 4p.
Dawson, K.M. and Orchard, M.J., (1981): Regional metallogeny of the Northern Cordillera:
biostratigraphy, correlation and metallogenic significance of bedded barite occurrences in
eastern Yukon and western District of Mackenzie, Current Research, Part C; Geological
Survey of Canada, Paper 82-1C, pages 31-35.
Fritz, W.H., (1979): Cambrian stratigraphy in the northern Rocky Mountains, British Columbia;
in Current Research, Part B, Geological Survey of Canada, Paper 79-1B, pages 99-109.
Gabrielse, H., (1975): Geology of Fort Grahame (East 1/2) map area, British Columbia:
Geological Survey of Canada, Paper 75-33.
- 86 -
Gabrielse, H., (1981): Stratigraphy and structure of Road River and associated strata in Ware
(west half) map area, northern Rocky Mountains, British Columbia; in Current Research,
Part A, Geological Survey of Canada, Paper 81-1a, pages 201-207.
Gabrielse, H., (1984): Major dextral transcurrent displacements along the northern Rocky
Mountain trench and related lineaments in north-central British Columbia; Geological
Society of America Bulletin, volume 96, pages 1-24
Goodfellow, W.D. and Jonasson, I.R., (1986a): Geology and geochemistry of the Howards Pass
Zn-Pb Deposits, Yukon: Constraints on metal source, migration and concentration; in The
Genesis of Stratiform Sediment-Hosted Lead and Zinc Deposits: Conference Proceedings,
R.J.W. Turner and M.T. Einaudi, (editors), Stanford University Publications, pages 22-29
Goodfellow, W.D., and Jonasson, I.R., (1986b, Environment of formation of the Howards Pass
(XY) Zn-Pb Deposit, Selwyn Basin, Yukon; in Mineral Deposits of Northern Cordillera,
J. Morin (editor), Canadian Institute of Mining and Metallurgy, Special Volume 37, pages
19-50.
Gordey, S.P., Abbott, J.G., and Orchard, M.J., (1981): Devono-Mississippian (Earn Group) and
younger strata in east-central Yukon; in Current Research, Part B, Geological Survey of
Canada, Paper 82-1B, pages 93-100.
Gustafson, L.B. and Williams, N., (1981): Sediment-hosted stratiform deposits of copper, lead,
and zinc; Economic Geology, 75th Anniversary Volume, pages 139-178
Hodgson, G.D., (1980): Dog claims, Omineca M.D., Geology, 1980; B.C. Ministry of Energy,
Mines and Petroleum Resources, Assessment Report 8673, 7 pages.
Jackson D.E., Steen, B., and Sykes, D., (1965): Stratigraphy and graptolite zonation of the
Kechika and Sandpile groups in northeastern British Columbia; Bulletin of Canadian
Petroleum Geology, volume 13, pages 139-154.
Jefferson, C.W., Kilby,D.B., Pigage, L.C. and Roberts, W.J., (1983): The Cirque barite-leadzinc deposits, northeast British Columbia; in Short Course in Sediment-hosted Stratiform
Lead-zinc Deposits, D.F. Sangster, (editor), Mineralogical Association of Canada, pages
121-140
Johnson, N. and Metcalfe, P. (2007): Summary report on the 2006 Akie diamond drill project;
internal company report (preliminary draft)
Journel, A.G., and Huijbregts, Ch. J., (1978): Mining Geostatistics: London, Academic Press,
600p
Kapusta, J. (1995): Gataga Project Cardiac Creek Horizon – Metal Zonation; Inmet Mining
Corporation internal report
Lewis, P. 1997: Structural Geology of the Akie Deposit, Drill Hole and Geological Mapping
Review, Inmet Mining Corporation, internal company report.
Lydon, J.W., (1983): Chemical parameters controlling the origin and deposition of sedimenthosted, stratiform lead-zinc deposits; in Short Course in Sedimentary Stratiform Lead
Zinc Deposits, D.F. Sangster, (editor), Mineralogical Association of Canada, pages 175250.
Lydon, J.W., Goodfellow, W.D. and Jonasson, I.R., (1986): Stratiform baritic deposits of the
Selwyn Basin: Geology, geochemistry, and genesis; in The Genesis of Stratiform
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Sediment-Hosted Lead and Zinc Deposits: Conference Proceedings, R.J.W. Turner and
M.T. Einaudi, (editors), Stanford University Publications, pages 99-103.
MacIntyre, D.G. (1991): Sedex - Sedimentary-exhalative deposits, in Ore Deposits, Tectonics
and Metallogeny in the Canadian Cordillera, W.J. McMillan, (coordinator), B.C. Ministry
of Energy, Mines and Petroleum Resources, Paper 1991-4, pages 25-69.
MacIntyre, D.G. (1992): Geological setting and genesis of sedimentary exhalative barite and
barite-sulfide deposits, Gataga district, northeastern British Columbia; Exploration and
Mining Geology, volume 1, pages 1-20.
MacIntyre, D.G., (1980): Driftpile Creek - Akie River project; Geological Fieldwork 1979, B.C.
Ministry of Energy, Mines and Petroleum Resources, Paper 1980-1, pages 55-67.
MacIntyre, D.G., (1981): Geologic setting of recently discovered stratiform barite-sulphide
deposits in northeast British Columbia; Canadian Institute of Mining and Metallurgy
Bulletin, volume 75, no. 80, pages 99-113.
MacIntyre, D.G., (1981a): Geology of the Akie river Ba-Pb-Zn mineral district; B.C. Ministry
of Energy, Mines and Petroleum Resources, Preliminary Map 44.
MacIntyre, D.G., (1983): Geology and stratiform barite-sulphide deposits of the Gataga District,
northeastern British Columbia; in Short Course on Sediment Hosted Stratiform Lead-Zinc
Deposits, D.F. Sangster (editor), Mineralogical Association of Canada, pages 85-120.
MacIntyre, D.G., (1998): Geology, Geochemistry and Mineral Deposits of the Akie River Area,
Northeast British Columbia, B.C. Ministry of Energy and Mines, Bulletin 103, 93 pages.
MacIntyre, D.G., (2005): Geological report on the Akie Property; technical 43-101 report filed
on the SEDAR website, October 2005.
McClay, K.R., Insley, M.W. and Anderton, R., (1989): Inversion of the Kechika Trough,
northeastern British Columbia, Canada; in Inversion Tectonics, Cooper, M.A. and
Williams, G.D. (editors), Geological Society Special Publications No. 44, pages 235-257.
McClay, K.R., Insley, M.W., Way, N.A., and Anderton, R., (1988): Tectonics and
mineralization of the Kechika Trough, Gataga area, northeastern British Columbia;
Current Research, Part E, Geological Survey of Canada, Paper 88-1E, pages 1-12.
Norford, B.S., (1979): Lower Devonian graptolites in the Road River formation, northern
British Columbia, 94B,C,F; Current Research, Part A, Geological Survey of Canada,
Paper 79-1A, pages 383-384.
Paradis, S, Nelson, J.L., and Irwin, S.E.B. (1998): Age constraints on the Devonian shalehosted Zn-Pb-Ba deposits, Gataga District, Northeastern British Columbia, Canada;
Economic Geology, volume 93, pages 184-200.
Pelzer, E.E., (1966): Mineralogy, geochemistry and stratigraphy of the Besa River shale, British
Columbia; Canadian Petroleum Geology Bulletin, volume 14, pages 273-321.
Pigage, L.C., (1986): Geology of the Cirque barite-zinc-lead-silver deposits, Northeastern
British Columbia; in Mineral Deposits of Northern Cordillera, J. Morin (editor), Canadian
Institute of Mining and Metallurgy, Special Volume 37, pages 71-86.
Price, R.A., (1986): The southeastern Canadian Cordillera: thrust faulting, tectonic wedging and
delamination of the lithosphere; Journal of Structural Geology, volume 9, pages 239-254.
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Roberts, W.J., (1978): Geological and geochemical report on the Fluke Group; B.C. Ministry of
Energy, Mines and Petroleum Resources, Assessment Report 7270, 14 pages.
Roberts, W.J., (1979): Geological report on the Elf Group; B.C. Ministry of Energy, Mines and
Petroleum Resources, Assessment Report 7303, 10 pages.
Russell, M.J., (1983): Major sediment-hosted exhalative zinc + lead deposits: formation from
hydrothermal convection cells that deepen during crustal extension; in Short Course in
Sediment-hosted Stratiform Lead-zinc Deposits, D.F. Sangster, (editor), Mineralogical
Association of Canada, pages 251-282.
Taylor, G.C. and MacKenzie, W.S., (1970): Devonian stratigraphy of northeast British
Columbia; Geological Survey of Canada, Bulletin 186.
Tempelman-Kluit, D.J., (1977): Stratigraphy and structural relations between the Selwyn Basin,
Pelly Cassiar Platform, and Yukon Crystalline Terrane in the Pelly Mountains, Yukon; in
Report of Activities, Part A Geological Survey of Canada, paper 76-1A, pages 223-227.
Vanwermeskerken, M. and Metcalfe P., (1996): Summary report on the 2005 Akie diamond
drill project, internal company report filed for assessment credit.
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22.0 CERTIFICATES OF AUTHORS
I, Donald George MacIntyre, Ph.D., P.Eng., do hereby certify that:
1. I am an independent consulting geologist providing services through D.G. MacIntyre and Associates Ltd.
a wholly owned company incorporated December 10, 2004 in the Province of British Columbia
(registration no. BC0710941). My residence and business address is 4129 San Miguel Close, Victoria,
British Columbia, Canada, V8N 6G7.
2. I graduated with a B.Sc. degree in geology from the University of British Columbia in 1971. In addition, I
obtained M.Sc. and Ph.D. degrees specializing in Economic Geology from the University of Western
Ontario in 1975 and 1977 respectively.
3. I have been registered with the Association of Professional Engineers and Geoscientists of British
Columbia since September, 1979, registration number 11970. I am a Fellow of the Geological Association
of Canada and a member of the British Columbia Association for Mineral Exploration.
4. I have practiced my profession as a geologist, both within government and the private sector, in British
Columbia and parts of the Yukon for over 30 years. Work has included detailed geological investigations
of mineral districts, geological mapping, mineral deposit modeling and building of geoscientific
databases. I have directly supervised and conducted geologic mapping and mineral property evaluations,
published reports and maps on different mineral districts and deposit models and compiled and analyzed
data for mineral potential evaluations.
5. I have read the definition of “qualified person” set out in National Instrument 43-101 (“NI 43-101”) and
certify that by reason of my education, affiliation with a professional association (as defined in NI 43-101)
and past relevant work experience, I fulfill the requirement to be a “qualified person” for the purposes of
NI 43-101.
6. I am responsible for sections of the technical report titled “Technical Report: Geology, Diamond Drilling
and Preliminary Resource Estimation, Akie Zinc-Lead-Silver Property, Northeast British Columbia,
Canada” dated May 31, 2008. (the “Technical Report”). The effective date of this Technical Report is
March 29, 2008. Sections not written by myself are noted in the text. I visited the Akie property on
August 26, 2005.
7. I have not had prior involvement with the property that is the subject of the Technical Report.
8. I am not aware of any material fact or material change with respect to the subject matter of the Technical
Report the omission of which would make the Technical Report misleading.
9. I am independent of the issuer applying all of the tests in Section 1.5 of National Instrument 43-101.
10. I have read National Instrument 43-101 and Form 43-101F1, and the Technical Report has been prepared
in compliance with that instrument and form.
11. I consent to the filing of the Technical Report with any stock exchange and other regulatory authority and
any publication by them, including electronic publication in the public company files on their websites
accessible by the public, of the Technical Report.
Dated this 31st of May, 2008
D.G. MacIntyre, Ph.D. P.Eng.
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I, Robert Sim, P.Geo, do hereby certify that:
1.
I am an independent consultant, SIM Geological Inc., located at 6810 Cedarbrook Place, Delta, BC,
Canada, V4E 3C5, incorporated December 20, 2005 (BC 0743802).
2.
I graduated from Lakehead University with an Honours Bachelor of Science (Geology) in 1984.
3.
I am a member of the Association of Professional Engineers and Geoscientists of British Columbia,
License Number 24076.
4.
I have practiced my profession continuously for 24 years and have been involved in mineral exploration,
mine site geology and operations, mineral resource and reserve estimations and feasibility studies on
numerous underground and open pit base metal and gold deposits in Canada, the United States, Central
and South America, Europe, Asia, Africa and Australia.
5.
I have read the definition of “qualified person” set out in National Instrument 43-101 (“NI 43-101”) and
certify that by reason of my education, affiliation with a professional association (as defined in NI 43-101)
and past relevant work experience, I fulfill the requirements to be a “qualified person” for the purposes of
NI 43-101.
6.
I am responsible for the preparation of sections 13 and 17 of the technical report titled “Technical Report:
Geology, Diamond Drilling and Preliminary Resource Estimation, Akie Zinc-Lead-Silver Property,
Northeast British Columbia, Canada””, dated May 31, 2008 (the “Technical Report”). The effective date
of this Technical Report is March 29, 2008. I personally visited the site on October 16-17, 2007.
7.
I have not had prior involvement with the property that is the subject of this Technical Report.
8.
As of the date of this certificate, to the best of my knowledge, information and belief, the Technical
Report contains all scientific and technical information that is required to make the Technical Report not
misleading.
9.
I am independent of the issuer applying all of the tests in Section 1.4 of National Instrument 43-101.
10. I have read National Instrument 43-101 and Form 43-101F1, and the Technical Report has been prepared
in compliance with that instrument and form.
Dated this 31st Day of May, 2008.
Robert Sim, P. Geo.
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APPENDIX A. SEDEX DEPOSIT MODEL DESCRIPTION
SEDIMENTARY EXHALATIVE Zn-Pb-Ag
E14
by Don MacIntyre
British Columbia Geological Survey
MacIntyre, Don (1995): Sedimentary Exhalative Zn-Pb-Ag, in Selected British Columbia
Mineral Deposit Profiles, Volume 1 - Metallics and Coal, Lefebure, D.V. and Ray, G.E.,
Editors, British Columbia Ministry of Energy of Employment and Investment, Open File
1995-20, pages 37-39.
IDENTIFICATION
SYNONYMS: Shale-hosted Zn-Pb-Ag; sediment-hosted massive sulphide Zn-Pb-Ag;
Sedex Zn- Pb.
COMMODITIES (BYPRODUCTS): Zn, Pb, Ag, (minor Cu, barite).
EXAMPLES (British Columbia - Canada/International): Cirque, Sullivan, Driftpile;
Faro, Grum, Dy, Vangorda, Swim, Tom and Jason (Yukon, Canada), Red Dog (Alaska,
USA), McArthur River and Mt. Isa (Australia); Megen and Rammelsberg (Germany).
GEOLOGICAL CHARACTERISTICS
CAPSULE DESCRIPTION: Beds and laminations of sphalerite, galena, pyrite,
pyrrhotite and rare chalcopyrite, with or without barite, in euxinic clastic marine
sedimentary strata.. Deposits are typically tabular to lensoidal in shape and range from
centimetres to tens of metres thick. Multiple horizons may occur over stratigraphic
intervals of 1000 m or more.
TECTONIC SETTING: Intracratonic or continental margin environments in faultcontrolled basins and troughs. Troughs are typically half grabens developed by
extension along continental margins or within back-arc basins.
DEPOSITIONAL ENVIRONMENT / GEOLOGICAL SETTING: Restricted second and
third order basins within linear, fault-controlled marine, epicratonic troughs and basins.
There is often evidence of penecontemporaneous movement on faults bounding sites
of sulphide deposition. The depositional environment varies from deep, starved marine
to ? shallow water restricted shelf.
AGE OF MINERALIZATION: The major metallogenic events are Middle Proterozoic,
Early Cambrian, Early Silurian and Middle to Late Devonian to Mississippian. The
Middle Proterozoic and Devonian-Mississippian events are recognized worldwide. In
the Canadian Cordillera, minor metallogenic events occur in the Middle Ordovician and
Early Devonian.
HOST/ASSOCIATED ROCK TYPES: The most common hostrocks are those found in
euxinic, starved basin environments, namely, carbonaceous black shale, siltstone,
cherty argillite and chert. Thin interbeds of turbiditic sandstone, granule to pebble
conglomerate, pelagic limestone and dolostone, although volumetrically minor, are
common. Evaporites, calcareous siltstone and mudstone are common in shelf settings.
Small volumes of volcanic rocks, typically tuff and submarine mafic flows, may be
present within the host succession. Slump breccia, fan conglomerates and similar
deposits occur near synsedimentary growth faults. Rapid facies and thickness changes
are found near the margins of second and third order basins. In some basins high-level
mafic sills with minor dikes are important.
DEPOSIT FORM: These deposits are stratabound, tabular to lens shaped and are
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typically comprised of many beds of laminae of sulphide and/or barite. Frequently the
lenses are stacked and more than one horizon is economic. Ore lenses and
mineralized beds often are part of a sedimentary succession up to hundreds of metres
thick. Horizontal extent is usually much greater than vertical extent. Individual laminae
or beds may persist over tens of kilometres within the depositional basin.
TEXTURE/STRUCTURE: Sulphide and barite laminae are usually very finely crystalline
where deformation is minor. In intensely folded deposits, coarser grained, recrystallized
zones are common. Sulphide laminae are typically monomineralic.
ORE MINERALOGY (Principal and subordinate): The principal sulphide minerals are
pyrite, pyrrhotite, sphalerite and galena. Some deposits contain significant amounts of
chalcopyrite, but most do not. Barite may or may not be a major component of the ore
zone. Trace amounts of marcasite, arsenopyrite, bismuthinite, molybdenite, enargite,
millerite, freibergite, cobaltite, cassiterite, valleriite and melnikovite have been reported
from these deposits. These minerals are usually present in very minor amounts.
ALTERATION MINERALOGY: Alteration varies from well developed to nonexistent. In
some deposits a stockwork and disseminated feeder zone lies beneath, or adjacent to,
the stratiform mineralization. Alteration minerals, if present, include silica, tourmaline,
carbonate, albite, chlorite and dolomite. They formed in a relatively low temperature
environment. Celsian, Ba-muscovite and ammonium clay minerals have also been
reported but are probably not common.
ORE CONTROLS: Favourable sedimentary sequences, major structural breaks,
basins.
GENETIC MODEL: The deposits accumulate in restricted second and third order
basins or half grabens bounded by synsedimentary growth faults. Exhalative centres
occur along these faults and the exhaled brines accumulate in adjacent seafloor
depressions. Biogenic reduction of seawater sulphate within an anoxic brine pool is
believed to control sulphide precipitation.
ASSOCIATED DEPOSIT TYPES: Associated deposit types include carbonate-hosted
sedimentary exhalative, such as the Kootenay Arc and Irish deposits (E13), bedded
barite (E17) and iron formation (F10).
EXPLORATION GUIDES
GEOCHEMICAL SIGNATURE: The deposits are typically zoned with Pb found closest
to the vent grading outward and upward into more Zn-rich facies. Cu is usually found
either within the feeder zone of close to the exhalative vent. Barite, exhalative chert and
hematite-chert iron formation, if present, are usually found as a distal facies. Sediments
such as pelagic limestone interbedded with the ore zone may be enriched in Mn. NH3
anomalies have been documented at some deposits, as have Zn, Pb and Mn haloes.
The host stratigraphic succession may also be enriched in Ba on a basin-wide scale.
GEOPHYSICAL SIGNATURE: Airborne and ground geophysical surveys, such as
electromagnetics or magnetics should detect deposits that have massive sulphide
zones, especially if these are steeply dipping. However, the presence of graphite-rich
zones in the host sediments can complicate the interpretation of EM conductors. Also, if
the deposits are flat lying and comprised of fine laminae distributed over a significant
stratigraphic interval, the geophysical response is usually too weak to be definitive.
Induced polarization can detect flat-lying deposits, especially if disseminated feeder
zones are present.
OTHER EXPLORATION GUIDES: The principal exploration guidelines are appropriate
sedimentary environment and stratigraphic age. Restricted marine sedimentary
sequences deposited in an epicratonic extensional tectonic setting during the Middle
Proterozoic, Early Cambrian, Early Silurian or Devono-Mississippian ages are the most
favourable.
ECONOMIC FACTORS
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GRADE AND TONNAGE: The median tonnage for this type of deposit worldwide is 15
Mt, with 10 % of deposits in excess of 130 Mt (Briskey, 1986). The median grades
worldwide are Zn - 5.6%, Pb - 2.8% and Ag - 30 g/t. The Sullivan deposit, one of the
largest deposits of this type ever discovered, has a total size of more than 155 Mt
grading 5.7% Zn, 6.6% Pb and 7 g/t Ag. Reserves at the Cirque are 32.2 Mt grading
7.9% Zn, 2.1% Pb and 48 g/t Ag.
ECONOMIC LIMITATIONS: The large, near-surface deposits are amenable to high
volume, open pit mining operations. Underground mining is used for some deposits.
IMPORTANCE: Sedimentary exhalative deposits currently produce a significant
proportion of the world’s Zn and Pb. Their large tonnage potential and associated Ag
values make them an attractive exploration target.
REFERENCES
Briskey, J.A. (1986): Descriptive Model of Sedimentary Exhalative Zn-Pb; in Mineral
Deposit Models, Cox, D.P. and Singer, D.A., Editors, U.S. Geological Survey, Bulletin
1693, 379 pages.
Carne, R.C. and Cathro, R.J. (1982): Sedimentary-exhalative (Sedex) Zn-Pb-Ag
Deposits, Northern Canadian Cordillera; Canadian Institute of Mining and Metallurgy,
Bulletin, Volume 75, pages 66-78.
Gustafson, L.B. and Williams, N. (1981): Sediment-hosted Stratiform Deposits of
Copper, Lead and Zinc; in Economic Geology Seventy-fifth Anniversary Volume, 19051980, Skinner, B.J., Editor, Economic Geology Publishing Co., pages 139-178.
Large, D.E. (1981): Sediment-hosted Submarine Exhalative Sulphide Deposits - a
Review of their Geological Characteristics and Genesis; in Handbook of Stratabound
and Stratiform Ore Deposits, Wolfe, K.E., Editor, Geological Association of Canada,
Volume 9, pages 459-507.
Large, D.E. (1983): Sediment-hosted Massive Sulphide Lead-Zinc Deposits; in Short
Course in Sedimentary Stratiform Lead-Zinc Deposits, Sangster, D.F., Editor,
Mineralogical Association of Canada, pages 1-29.
MacIntyre, D.G. (1991): Sedex - Sedimentary-exhalative Deposits, in Ore Deposits,
Tectonics and Metallogeny in the Canadian Cordillera, McMillan, W.J., Coordinator, B.
C. Ministry of Energy, Mines and Petroleum Resources, Paper 1991-4, pages 25- 69.
Sangster, D.F. (1986): Classifications, Distribution and Grade-Tonnage Summaries of
Canadian Lead-Zinc Deposits; Geological Survey of Canada, Economic Geology
Report 37, 68 pages.
December 8, 1992
[
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