Research plan for field studies at the Hyrkkiil8 native

Transcription

Working report 97-49e
Research plan for field studies
at the Hyrkkiil8 native copper
mineralization, SW Finland
Lasse _Ahonen
Geological Survey of Finland
Nuria Marcos
Helsinki University of Technology
Markku Paananen, Seppo Paulamaki
October 1997
POSIVA OY
·
Mikonkatu 15 A, FIN-00100 HELSINKI, FINLAND
Tel. +358-9-2280 30
Fax +358-9-2280 3 7 19
Working report 97-49e
Research plan for field studies
at the Hyrkk018 native copper
mineralization, SW Finland
Lasse Ahonen
Nuria Marcos
Helsinki University of Technology
Markku Paananen, Seppo Paulamaki
October 1997
TEKIJAORGANISAATIOT:
Geologian tutkimuskeskus
PL 96 (Betonimiehenkuja 4)
02151 ESPOO
Teknillinen korkeakoulu
Insin66rigeologian ja geofysiikan lab.
PL 6200 (Vuorimiehentie 2 A)
02015 TKK
TILAAJA:
TILAAJAN YHDYSHENKILO:
Posiva Oy
Mikonkatu 15 A
00100 HELSINKI
Uo..+~
TILAUSNUMEROT:
Margit Snellman
9600/97/MVS
960 1197/MVS
TEKIJAORGANISAATIOIDEN
YHDYSHENKILOT:
~~
Lasse Ahonen
Posiva Oy
GTK
~v\ CL 'tl~i?.
Nuria Marcos
TKK
TYORAPORTTI -97 -49e
RESEARCH PLAN FOR FIELD
STUDIES AT THE HYRKKOLA
NATIVE COPPER MINERALIZATION,
SW FINLAND
TARKASTAJAT:
7~~Paavo Vuorela
proj ektipaallikko
GTK
Heikki Niini
professori
TKK
Working reports contain information on work in progress
or pending completion.
The conclusions and viewpoints presented in the report
are those of author(s) and do not necessarily coincide
with those of Posiva.
ABSTRACT
Lasse Ahonen*, Nuria Marcos** , Markku Paananen*, Seppo Paulamaki*
*Geological Survey of Finland
**Helsinki University of Technology, Laboratory of Engineering Geology and
Geophysics
RESEARCH PLAN FOR FIELD STUDIES AT THE HYRKKOLA NATIVE
COPPER MINERALIZATION, SW FINLAND
The small uranium-mineralization of Hyrkkola in Nummi-Pusula was found in
systematic ore exploration studies of the Geological Survey of Finland in the beginning
of 1980's. A special feature of this mineralization is the occurrence of native copper
together with uranium in narrow pegmatite veins. During the ore exploration phase,
five cored boreholes were drilled to the area, so that there is preliminary information
on the location and mode of occurrence of metallic copper in the bedrock of the site.
However, groundwater chemistry and hydrogeological conditions are not yet known,
because the old boreholes are blocked.
According to the research plan presented in this report, one or more new boreholes
would be drilled to the site for further mineralogical examinations and for groundwater
research.
The purpose of the proposed research is to study the behaviour of native copper in the
bedrock as a natural analogue to the copper canisters placed into the bedrock. The
study will comprice 1) comparison of the groundwater composition in Hyrkkola with
the groundwaters of the candidate sites for nuclear waste disposal; 2) study of the
possible secondary , low-temperature alteration of metallic copper, especially if in
contact with groundwater; 3) isotopic studies aiming at estimation of the age and timescale of the possible alteration reactions.
KEYWORDS: copper, natural analogue, groundwater, corrosion
TIIVISTELMA
Lasse Ahonen*, Nuria Marcos**, Markku Paananen*, Seppo Paulamaki*
*Geologian tutkimuskeskus
*Teknillinen korkeakoulu, lnsin66rigeologian ja geofysiikan laboratorio
HYRKKOLAN METALLISEN KUPARIN ESIINTYMAN KENTTATUTKIMUSSUUNNITELMA
Nummi-Pusulan Hyrkkolassa sijaitseva pieni uraanimineralisaatio loytyi Geologian
tutkimuskeskuksen 1980 luvun alussa tekemissa systemaattisissa tutkimuksissa.
Esiintyman erikoispiirre on kapeissa pegmatiittijuonissa yhdessa uraanin kanssa
esiintyva puhdas metallinen kupari. Alueelle kairattiin malminetsintatutkimusten
yhteydessa viisi kairareikaa, joten luonnonkuparin esiintymispaikoista ja esiintymistavasta on alustavaa tietoa naiden kairausnaytteiden perusteella. Alueen kalliopohjaveden ominaisuuksista ei kuitenkaan ole saatu tietoa, koska kairareiat ovat tukkeutuneet.
Tassa raportissa esitetaan suunnitelma, jonka mukaan alueelle kairattaisiin yksi tai
useampia uusia kairareikia mineralogisia jatkotutkimuksia ja kalliopohjavesitutkimuksia
varten.
Tyon tarkoituksena on tutkia metallisen luonnonkuparin kayttaytymista kalliossa
luonnonanalogiana kuparikapselille, joka on sijoitettu syvalle peruskallioon. Tutkimuksessa selvitetaan 1) vastaako Hyrkkolan tutkimusalueen pohjavesi ydinjatteen
loppusijoitusalueiden pohjavetta; 2) onko metallisessa kuparissa havaittavissa sekundaarista matalan lampotilan muuttumista (korroosiota), erityisesti sen ollessa kosketuksessa
pohjaveteen; 3) isotooppimenetelmin mahdollisten muuttumisreaktioiden ikaa ja
aikaskaalaa.
AV AINSANAT: kupari, luonnonanalogia, pohjavesi, korroosio
PREFACE
This study has been performed at the Geological Survey of Finland (GTK) and at the
Helsinki University of Technology (TKK) on contracts for Posiva Oy. The contact
persons were Margit Snellman and Juhani Vira at Posiva, Lasse Ahonen at GTK, and
Nuria Marcos at TKK.
CONTENTS
ABSTRACT
TIIVISTELMA
PREFACE
1
INTRODUCTION
1
1.1
General
1
1.2
Background data
2
2
TARGET AND STRATEGY OF THE HYRKKOLA STUDY
3
3
DESCRIPTION AND DEFINITION OF THE RESEARCH SITE
5
3.1 Regional geology
5
3.2 Geology of the Hyrkkola study site
5
4
3.2.1 Rock types
7
3.2.2 Tectonics
9
3.3 Drilling plan
10
3.4 Quaternary geology and retreat of last glaciation
19
3.5 Soil and groundwater studies of the site
21
RESEARCH PLAN
22
4.1 sampling and monitoring during drilling
22
4.2 core sample research
23
4.2.1 sample analyses
23
4.3 Groundwater sampling and analysis
25
4.3.1 sampling and field measurements
25
4.3.2 Chemical determinations
26
4.4 Other studies
28
5 DISCUSSION AND CONCLUSIONS
29
6 REFERENCES
32
1
1
INTRODUCTION
1.1
ceneral
Chemical stability of copper as a canister material for spent nuclear fuel has been shown
by laboratory studies as well as by thermodynamic considerations (e.g., Engman and
Hermansson 1994, Ahonen 1995, and references therein). These studies describe well
the behaviour of simplified systems, while natural analogues are most suitable in
demonstrating the long-term behaviour of complex natural systems. The durability of
copper has been studied by means of its archeological analogs, mainly bronzes, which
have been preserved hundreds or thousands of years in the near-surface environments
(e.g., Hallberg et al. 1988, Miller et al. 1994).
Among the possible corrosion-resistant canister materials, metallic copper is the only
one for which lifetimes up to billions of years can also be demonstrated by means of
natural analogues. The well-known basalt-conglomerate-hosted native copper deposits
of Keweenaw Peninsula in Michican were formed about 1.1 Ga ago, and metallic
copper was the stable phase of copper during the hydrothermal alteration of the deposit
at T ~ 100° - 200° C. According to Schwartz (1996), "There is general agreement that
the bulk of native copper has remained texturally stable since the Precambrian
metamorphic-hydrothermal event that produced the mineralization. Neither sulfidization
nor oxidation of native copper is of any importance".
Many of the known occurrences of native copper are associated with basalts originally
extruded onto land, being subjected to mildly oxygenated conditions and escape of
sulfur. Other typical occurrences are related to mildly oxidized zones of copper sulfide
deposits. The physicochemical conditions and mineral parageneses of those occurrences
differ from the conditions prevailing within the planned deep nuclear waste repository
in Finland. Detailed studies on the behaviour of pure metallic copper in the crystalline
bedrock environment in contact with groundwater are still lacking.
In this report, we are considering the possibilities to study the native copper occurrence
of HyrkkoHi, SW Finland, as a natural analogue to the long-term behaviour of copper
canister placed in the bedrock. The HyrkkoHi U-Cu occurrence is hosted by the
Svecofennian schist belt (crystalline bedrock), thus having mineralogical and
hydrogeological characteristics similar to those of the sites considered for the actual
disposal of nuclear waste in Finland.
2
1.2
Background data
Systematic mapping of the bedrock of the Somero map sheet (map sheet 2024, scale
1:100 000) was initiated in late 1930's, and the explanation to the map of rocks was
published by Simonen (1956). A map of the Quaternary deposits of the same area was
published in 1970's (Haavisto et al. 1980). A more detailed mapping of the Quaternary
deposits around HyrkkoHi (map sheet 2024 10, scale 1:20 000) has been carried out
during the last years.
Studies at the HyrkkoHi site were initiated in the beginning of 1980's when the
Geological Survey of Finland (GTK) carried out car-borne radiometric surveys in the
small uranium-bearing province of Nummi-Pusula, being first discovered by airborne
measurements.
During the spring 1982, anomalous high uranium and thorium concentrations were
detected from a drilled well in the village of HyrkkoHi (Hyyppa and Juntunen 1983).
During the autumn 1982, detailed study of the quaternary formations were carried out
at a restricted area defined by the radiometric anomalies. Surface of the crystalline
bedrock was exposed by 16 research pits and trenches (length up to 15 meters)
excavated to the till cover (Nenonen and Hakala 1983). Metallic copper and cupric salts
associated with uranium minerals were found in one of the trenches, boulders containing
metallic copper were also found from the till and from the surface. Copper content of
till samples was also analyzed.
Airborne low-altitude geophysical measurements (radiometric, electromagnetic, and
magnetic) were carried out during 1978 - 1985, and the results are available as maps in
the scale 1:100000 (map sheet 2024). Detailed-scale geophysical ground measurements
(radiometric, electromagnetic, and magnetic) were carried out during 1983 around the
village of Hyrkkola. Distance between measurement lines were 50 meters.
During 1984 geological mapping was done in the area southeast of Hyrkkola site
(Yrjola 1984). A geological map showing the uranium discoveries of Nummi-Pusula
area was published in 1986 (Raisanen 1989). During years 1983 and 1984, five cored
boreholes (diameter 46 mm) were also drilled in the Hyrkkola study area. Because the
drilling sites were on cultivated land, casings were removed soon after the work was
finished. The drillcores were studied by the geologists, reports are available at GTK,
and the drillcores and thin sections are stored at GTK. The rock surface in the field area
was also sampled by percussion drilling through the soil.
Later, Marcos (1996) made a detailed mineralogical study on the occurrence of metallic
copper in the drillcores. A particular feature observed was the existence of native copper
together with a low-temperature copper sulfide associated with fracturing.
3
2
TARCET AND STRATECY OF THE HYRKKOLA STUDY
So far, it is known from the mineralogical studies that native copper occurs in the
bedrock of the study site. The mineral paragenesis and mode of occurrence of metallic
copper in pegmatite veins suggest that it has been crystallized during the late stage of
Svecokarelidic orogeny about 1.8 billion years ago (Marcos 1996). During the
geological history, hydrogeological and physicochemical conditions have varied in the
bedrock of the site.
It is not possible to unravel the complete and detailed history of the physicochemical
conditions, which the geological site has undergone since its formation. However, the
present hydrogeological conditions can be studied. Moreover, the evolution of the
conditions can then be extrapolated backwards to the end of last glaciation and, with
increasing uncertainty, even further. Isotopic studies of the groundwater and minerals
may give indications of the past conditions and phenomena, for instance the effects of
the last glaciation. Certain radioisotopes may give information about processes, which
have been active during the last 500 000 years.
The aim of the proposed study is 1) to determine the present hydro geological conditions
of the site, 2) to observe and investigate the reactions of metallic copper with the
groundwater using fresh core samples, and 3) to interpret the results by means of the
present knowledge of the possible reactions of copper. The final target is to shed light
on the long-term behaviour of metallic copper in the bedrock during a time span of the
latest ten to hundred thousands of years.
For this target, one or more new cored research boreholes have to be drilled to the site.
The main functions of the holes are: 1) to measure and analyze the composition and
physicochemical conditions of the groundwater that may recently be in contact with
metallic copper; 2) to get new, fresh drill-core samples containing metallic copper,
preferentially in contact with different types of groundwaters; 3) to characterize the
groundwater flow conditions in the copper-bearing fractures.
In the following, the proposed research activities are listed:
4
DRILL-CORE STUDY
-general mineralogy and composition
-paragenes1s
-accessones
-amounts (minerals/elements)
=>general budget of elemets, e.g., availability of sulfur
-alteration/reactions of Cu (in contact with water)
-microscale (microscopy)
-nanoscale (surface studies)
=>identification/observation of the processes
-fracture mineral study
-co-existing fracture minerals
-mineral generations
-isotope composition/ratios
=>history of the physico-chemical conditions in fracture
GROUNDWATER STUDY
-chemical composition of water
-main elements=> evolution/residence time
-minor/trace elements (e.g., Cu)
-redox elements Fe, S, (Cu) etc. => redox conditions
-gases (e.g., 0 2 ,H2)
-Eh, pH
=>redox conditions
-isotopes
=>G.W. evolution
-microbes (?)
OTHER STUDIES
-hydraulic conductivity of the fractures
-fracture apertures
5
3
DESCRIPTION AND DEFINITION OF THE RESEARCH SITE
3.1
Regional geology
HyrkkoHi study site is situated in the Somero map sheet area. The bedrock is composed
of Svecofennian metasediments and metavolcanics, which are penetrated by infracrustal
rocks, mainly quartz diorites, granodiorites and granites (Simonen 1956). The
supracrustal rocks are mainly mafic-intermediate volcanics (amphibolites and hornblende
gneisses ), which are mainly pyroclastics in origin. The metasediments include mica
schists and mica gneisses with cordierite and garnet porphyroblasts, and quartz-feldspar
gneisses. Most of the quartz-feldspar gneisses have been interpreted as arkose sandstones
(Simonen 1956). They are often closely associated with micaceous sediments and
gradually pass into mica schists and mica gneisses. In the stratigraphy the
metasediments are overlain by the metavolcanics. Regional metamorphism in Somero
area took place under the conditions of a low-pressure amphibolite facies (3 - 5 kbar,
550 - 650 OC; Latvalahti 1979, Schreurs & Westra 1986).
The foliation is predominantly vertical or steep in the main part of the map sheet. In the
near vicinity of the HyrkkoHi area it strikes roughly east-west with subvertical dip
(YrjoHi 1984). Folding is isoclinal with fold axes gently plunging to the east.
The structure of the Somero area is characterised by several post-folding fault and shear
zones (MakeHi 1989). The most prominent of them is the Hirsjarvi or Painio shear zone
(Makela 1989, Ploegsma 1989), which lies about 2 km north of Hyrkkola. It displays
a left-handed movement with both horizontal and vertical components (Makela op.cit.).
The bedrock of the near vicinity of Hyrkkola is shown in Figure 1.
3.2
ceology of the Hyrkkola study site
The rocks of the Hyrkkola site are deformed metasediments and metavolcanics, mainly
quartz-feldspar gneisses and amphibolites with uranium-bearing granite pegmatite veins
parallel to the foliation. The lithology of the Hyrkkola site is shown in Figure 2.
~
.....
HYRKKOLA
~
REGIONAL GEOLOGY
~
LEGEND:
Id
(I)
(1q
(5'
:::::s
'
,,,
p:>
.......
(1q
(I)
0
.......
0
(1q
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0
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g.
(I)
~X
,,
-\ -
-'>....
- - --- - ·-
\ " '--"'
. - - ' - - """"'- --~-- , _---- - - ;Q
PZ
/
/
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/
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....................
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10
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-:-
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-
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-===~ -~=-="=o
80
"
QUARTZ-FELDSPAR GNEISS
D
MICA GNEISS
-
GRANODIORITE
AMPHIBOLITE
-
PEGMATITE
==
p:>:
...........
-
_._
FOLIATION , STRIKE AND DIP
-+-
VERTICAL FOLIATION
/ / FAULT OR FRACTURE ZONE
~
"
INTERCALATIONS
.::::><::7 VEINS AND INCLUSIONS
PZ
.......
~p
~:.~:::;.::iGi:
:--'~)(-,..---+--
'-,
-
D
D
'\
OUTCROP
X
-v-
''
D
'
SCALE :
'\
PAINIO SHEAR ZONE
HYRKKOLA STUDY SITE
1000 M
0
-+- X
GEOLOGICAL SURVEY OF FINLAND
1997
+6713
,96
MODIFIED AFTER YRJOLA (1984)
0'\
7
3.2.1
Rock types
Amphibolites
Amphibolites are homogeneous or banded, fine to medium-grained rocks. The banded
amphibolites occur in the northern part of the study site (Fig. 2), and they have been
interpreted as pyroclastic sediments in origin. In places they contain calc-silicate (skarn)
layers, which have been boudinaged. The main minerals of the amphibolites are
hornblende, plagioclase (An32 _ 43 ) and minor diopside (Marcos 1996). Accessory and
secondary minerals are quartz, opaques (magnetite, hematite, pyrite, pyrrhotite,
graphite), epidote, clorite and clay minerals. Hematite, epidote and carbonates are
typical fracture-filling minerals.
Quartz-feldspar gneisses
Quartz-feldspar gneisses are light to dark gray, fine to medium-grained, homogeneous
or weakly banded. Medium-grained gneisses often show primary volcanic structures and
notable porosity (Marcos 1996). The main minerals are quartz, plagioclase (An20 _ 30).
Hornblende is the major accessory mineral, where gneisses are in contact with
amphibolites. Other accessory minerals are titanite, green apatite, zirkon and opaques
(magnetite, graphite, pyrite). Secondary minerals include epidote, chlorite and hematite.
Epidote and hematite occur in fracture fillings.
Mica gneiss
Medium-grained mica gneisses occur in the beginning of the borehole R303. The main
minerals are quartz, strongly seritized plagioclase and biotite. Garnet occur as
porphyroblasts. Other accessory minerals are opaques, chlorite and amphibole.
Granite pegmatites
The granite pegmatites occur as veins (0.05 - 5 m) parallel to the foliation in
amphibolites and quartz-feldspar gneisses. They are heterogeneous, medium to coarsegrained and light to red in color. The main minerals are quartz, feldspar (mostly
microcline) and black tourmaline (Marcos 1996). In the light granites tourmaline occur
as an accessory mineral. Other accessory minerals are green apatite, titanite, zirkon,
graphite, uraninite and native copper. Secondary minerals are epidote, hematite, cuprite,
chalcocite, calcite, uranophane and gummite.
8
49 5.700
~
~ 85 ' i
x -~---~
~
~
)(~-----
_
6715.000
---
-----~---~
x- - s5 -
_
l'!... __
---- ~ -x- . ---------
---------
)(
X
6 714. 90 0
---8
-------- ----=-=~~~ _;:.;:-;;:-
/
""'
___ ...
M16
A304
8 M15
6714. 80 0
_...
0
/
/
HYRKKOLA
Lithology
Legend:
D
Quartz-feldspar gneiss
00
Garnet
c::::J
Mica gneiss
....-<o
Foliation. strike and dip
Amphibolite/amphibole gneiss
/
Vertical foliation
-
SCALE:
Pegmatite
(B
Borehole
G-
Research pit or trench
X
Outcrop
compiled by: Seppo Paulam!lki
1997
Fig. 2. Bedrock of the HyrkkoHi study site.
9
3.2.2 Tectonics
The oldest structural feature that has been recognized is a penetrative metamorphic
foliation defined by parallel alignment of biotite or amphibole and a week
quartzofeldspathic segregation banding. The strike of the foliation is roughly east-west
and the dip about 80° towards south (Fig. 3). The quartz and granite veins are often
deformed into boudins parallel to the foliation. The folition is in places deformed into
isoclinal folds plunging gently to the east. These are occasionaly deformed by folds
plunging steeply to the northwest. The fracture zones, based on the interpretation of
topographic maps and low altitude aeromagnetic map, are presented in Figure 1.
Accordingly, the HyrkkoHi study site is situated between east-west and northwestsoutheast trending fracture zones. One of the interpreted fracture zones cuts the area
covered by the boreholes (Fig. 1). It may be represented in the boreholes either by a
fracture zone occuring between 39 - 63 m in the borehole 305 or by a fracture zone
between 94 - 109 m also in the borehole R305. However, it hasn't been possible to
connect them to any other borehole.
In the boreholes the open fractures are mostly coated by hematite, epidote, clay
minerals, calcite, and Fe-hydroxide (Marcos 1996). Epidote and calcite are the typical
fracture filling minerals. The drill cores are not oriented, so the real dips and dip
directions of the fractures are not known. However, concerning the dips of the boreholes
and the dip of the foliation in the outcrops, some of the hematite coated fractures seem
to be dipping gently to the north.
N
U9'
7.79'
11.5%
14.4%
18.2%
23.1%
2U%
P.!r4M
Fig. 3. Distribution of foliation in outcrops in the HyrkkoUi study site, N
=
26.
10
3.3
Drilling plan
New holes possibly drilled for the study of native copper should fulfill the following
requirements: 1) new samples of metallic copper should be obtained, 2) drillholes should
be available afterwards for groundwater sampling and other possible measurements.
In order to facilitate the planning of new drillings, a three-dimensional model of the central
study site has been compiled. Within this model, every single lithological unit can be
examined separately with respect to an arbitrary drillhole. The model covers the area
between drillholes R304 and R305, where X= 6714.830- 6714.930. The modelling has
been done utilizing programs PC-XPLOR, GEOMODEL (GemCom Services Inc., 1991,
1992) and Design Cad (America! Small Business Computers Inc., 1992). In Fig. 4, a threedimensional view of the target and the old drillholes is presented as an example.
Fig. 4. A three-dimensional view of the lithology of the central study site and the old
drillholes. Green= arnhibolite/amphibole gneiss, red= pegmatite, yellow= quartz-feldspar
gneiss. Main rock type (empty areas) is quartz-feldspar gneiss.
11
The starting point in drilling simulation was the location of the drillhole on the ground
surface at the southern side of the road near the eastern gable of the barn (X= 6714.874,
Y = 495.720, Fig. 5). This location was noticed optimal for practical reasons, and it is
suitable also from the geological point of view (Fig. 6).
The primary aim of the drilling is to intersect copper-bearing pegmatite veins, from which
the most interesting are related to a nearly E - W -trending formation of
amphibolite/amphibole gneiss. The best intersections nearby have been encountered from
the old drillhole R303 at the hole lengths of c. 110- 135 m. TheN- S -trending profile of
this old hole is located only 20 m to the W from the beginning of the new hole. Therefore
the azimuth of the new hole to the NW towards these intersections would maximize the
probability of pegmatite intersections.
The simulation of the forthcoming drilling was done by varying the azimuth of the hole
between 310° and 360° using the dip values of 45°, 60° and 75°. The results revealed, that
the hole should be steeply dipping in order to intersect the pegmatite veins at sensible
depths. This will also minimize the risk of collaption of the hole.
On the basis of the simulation, the following drilling directions are proposed:
1) azimuth 310°, dip 75°, drilling length c. 100 m.
2) azimuth 340°, dip 75°, drilling length c. 90 m.
Three-dimensional views of these proposals are presented in Figs. 7- 10. The diameters of
the holes have been exaggerated because of clarity. The predictions of intersections of
different geological units are presented in Tables 1 and 2. Possible deviation of the hole(s)
has not been taken into account.
12
'
\
' z"
, •
\
\ z \
\
•
\
----·--
f-
' z\
\
\
\
\ z\
\
\
\
\z
\
\
.,
\ PIS
\
\
\
~
\
\
scale 1:625
'\
\ z\
(")
0
\
(")
I
0
\
\
so m
P5 ' \
Fig. 5. The drilling place, starting point and horizontal projections of the new holes.
Locations of the nearest reseach pits and trenches (P5, P6, P7, P15, P16) and the
horizontal projection of the old drill hole 303 are marked. The interpreted structural
lineament is indicated by Z' s.
13
t/J
Q)
0
.c
::se0
:Q.c
2~
O:c::
>-+
----------~-3~
1)~
' ~~ JC
~
C)
-.c00
...:.J
Fig. 6. Planview of the lithologies and horizontal projections of the proposed drillholes.
14
F ILES
DISPLAY
EDIT
PARAMETER
LII'IES
POII'ITS
ARC/CIRC
SOLIDS
BLOCKS
SHADE
I'I OTES
SURFACES
II'IFO
COLORS
CURSOR
UIEW
H Po
Fig. 7. New drillhole with azimuth of310° and dip of75° (blue) and the pegmatite veins
to be intersected (red/brown). The old drillholes are printed with grey colour and the violet
rings around them mark the copper-bearing intersections. View from the E.
15
F ILES
DISPLAY
EDIT
PARAMETER
LINES
POINTS
ARC/CIRC
SOLIDS
BLOCKS
SHADE
NOTES
SURFACES
lNFO
COLORS
CURSOR
VIEW
H pI
rings around them mark the copper-bearing intersections. View from the N.
16
F ILES
DISPLAV
PIOTES
SURFACES
IPIFO
COLORS
CURSOR
UIEW
rings around them mark the copper-bearing intersections. View from the ESE.
17
BLOCKS
SHADE
PIOTES
SURFACES
UtFO
COLORS
CURSOR
UIEW
f1 Po
Fig.lO. New drillhole with azimuth of340° and dip of75° (blue) and the pegmatite veins
rings around them mark the copper-bearing intersections. View from the NNE.
- - - - - - - - -- - - -- - - - - - -- - - -- -- - --- -- -- -
-
18
Table 1. Prediction of lithology for proposal1 (310° I 75°).
Hole length (m)
Rock type
0-41
41-43
Pegmatite
43-60
60-63
Pegmatite
63 -73
Amphibolitelamphibole gneiss
73-82
82-92
92-94
Pegmatite
94- 110
110-
Table 2. Prediction of lithology for proposal2 (340° I 75°, R324).
Hole length (m)
Rock type
0-35
35-37
Pegmatite
37-52
52-55
Pegmatite
55-60
60-66
66-80
80-82
Pegmatite
82-96
96-
-
19
3.4
Quaternary geology and retreat of the last glaciation
Figure 11 shows a generalized map of the Quaternary deposits around Hyrkkola. The
study site is located between Salpausselka II and Salpausselka Ill, two major marginal
formations of the last glaciation. These glaciofluvial accumulations consist of eskers and
deltas, the material of which is predominantly sand, seconded by gravel. The coarse
material is situated in the proximal part of the deltas.
The most important esker sequence of the area is situated in the prominent NW-SE
trending Painio fracture valley and crush zone, terminating into a large delta formation
towards west to southwest of Hyrkkola. Regional crush zones limit the triangular,
strongly tectonized block around Hyrkkola. These zones also seem to have controlled
the flow of glacial meltwater, which was partly directed to the northern crush zone
passing the study site in a distance of about 1 to 2 kilometers.
The area inside the triangular Hyrkkola block is mainly covered by a thin (1 to
3 meters) layer of basal till. The area to the north of the Hyrkkola block is covered by
four to five meters thick layer of till, forming moraine ridges and hummocks.
Topographically, Hyrkkola block is on average 10 to 30 meters lower than the bedrock
block to the north of it. To the south of the Hyrkkola block, topographic level is about
30- 60 m lower than in Hyrkkola, and clay deposits become abundant.
The striae observations indicate that the last advance of the continental ice-sheet in the
area was from WNW (310°). The deglaciation of the area took place about ten thousand
years ago. For about 10200 years B.P., withdrawal of the ice margin had temporarily
stopped at about five kilometers southeast of the present Hyrkkola study site. The eskers
and deltas formed during that time are a part of the discontinuous chain of Salpausselka
II ice-margin formations, the ice margin being bordered by the Baltic Ice Lake.
In the year 8213 B.C., the Billingen channel in Central Sweden was opened, and the
waters of the Baltic Ice Lake discharged into the ocean, leading to a 25 meters lowering
of the water level in front of the glacier. Consequently, during the earliest phase of the
Yoldia See, the fractures in the bedrock of the present Hyrkkola site were subjected to
considerable hydraulic gradient, and intrusion of glacial meltwater into the fracture
zones may have taken place. One hundred year later the ice margin had withdrawn to
a new position, to the northwest of the present Hyrkkola site, and wide deltas of
Salpausselka Ill marginal formation were formed.
20
Cl)
Q.)
c
0
N
.c
Cl)
=
....
u
Cl
Cl
Cl
Q
Q
,...
·=·=):1:1:1:1:1:1:1:1:1:1::.;:l:1:1:1:j:H:I
,...
Fig. 11. Quaternary deposits around HyrkkoHi study site
I
.
21
3.5
soil and groundwater studies of the site
The sixteen research pits and trenches around the present study site were excavated to
places, where radiometric anomalies and/or copper-bearing surficial boulders had been
detected. Except for two pits, the surface of the crystalline bedrock was reached within
0.5 to 3 meters depth (Nenonen and Hakala 1983).
The bedrock of the site is mainly covered by a thin (about 1 to 2 meters) layer of
boulder-rich basal till. The exceptionally high amount of boulders in till is due to the
broken and weathered bedrock surface, the till material being of local origin.
Predominant direction of the till material is 305°- 315°, indicating the course of the last
glacial movement. In one of the research pits (P16, Fig. 5) an elder till bed was
encountered at a depth of about 2.5 meters. Direction of this till bed was 360°. The
material was very compact, and boulders were smaller than in the layer above.
The southern part of the study site is bordered by cultivated land, in which the
uppermost minerogenic layer is silt (thickness about 0.2 to 1 meter). According to the
drilling results, total thickness of the quaternary sediments in the field area is about 3
to 5 meters, probably increasing southwards.
Copper-bearing bedrock surface was encountered in one of the research trenches (P5).
Small amounts of metallic copper was observed as films in feldspar and as oxidized
"copper mold". Yellow spots of oxidized uranium salts and molybdenite was also
observed (Nenonen and Hakala 1983). The host rock of native copper, the reddish
uranium-, tourmaline- and apatite-bearing pegmatite was found in five of the pits or
trenches (e.g., P6).
Groundwater composition in wells around the village of HyrkkoHi have been analyzed
(Hyyppa and Juntunen 1983). One of the reasons initially activating the studies of the
site was an anomalously high concentration of uranium (2300 ppb) analyzed from a
drilled well in the village. In general, analyzed copper concentrations in the wells were
about 1 to 5 ppb, corresponding to average groundwater values in Finland. Copper
concentration in the well nearest to the known copper occurrence was 11 ppb, while the
highest concentration (29 ppb Cu) reported in the study was analyzed from a well
located about 5 kilometers from the village.
22
4
RESEARCH PLAN
4.1
sampling and monitoring during drilling
Drilling will be carried out using equipment for drill-hole diameter 76 mm for the
following reasons: 1) large amount (diameter 62 mm) of drill core facilitates the
fracture mineral studies; 2) the diameter better allows the use of all kinds of bore-hole
devices, and later monitoring of packed-off sections.
The primary sample obtained is the drill core. In addition to the lithology, information
on the distribution of the water-conducting fractures will be obtained. During drilling
these fractures are often observed by the driller, because they affect the penetration rate,
the water-injection pressure, and the amount and quality of the flushing water recovered.
These parameters are recorded by the geologist in communication with the driller.
Amount (flow rate) and chemical composition of flushing water (in and out) are going
to be monitored.
During the retrieval of the drill core, the geologist is supervising the work of drillers
assistant. Many of the cuts in the drill core are due to the removal of the drillcore from
the tubing and by the fitting of the core to the sample box. Because the cuts often
propagate along originally sealed fractures, first examination of the core should be done
during its removal from the drilling tube.
A more thorough examination of the core, as well as an initial sampling of the fracture
surfaces will take place when the sample is properly assembled into the sample box.
However, if the solid material is sampled for microbial studies, the samples should be
taken aseptically (sterile gloves, breathe mask) immediately after the removal of the
core from the drilling tube.
During drilling flushing water is injected via the drilling rods and the water is recovered
outside the rods. Difference in the composition of water injected and water recovered
gives some preliminary information on composition of formation water (e.g., salinity
may be seen by measuring the electrical conductivity of flushing water).
23
4.2
core sample research
Analyzing major elements, and determining mineral composition, especially fracture
mineral and mineral surface composition provides data to be used in:
modelling of the water-rock interaction; an explanation to the groundwater
composition (e.g., aqueous speciation)
getting an approach to the mechanisms of mineral-surface reactions (basis to the
stability of copper or copper sulfide in the groundwater environment)
determining the elements/minerals controlling the Eh- and pH-conditions and
buffering capacities.
4.2.1
sample analyses
The determination of major and minor elements involved in water-rock interaction
processes is assessed by whole-rock chemical analyses. A minimun of 5 to 10 samples
is necessary in order to get representative results. The analytical methods considered are
XRF (X-ray fluorescence) for major elements analyses and ICP-MS (Inductively
coupled plasma- mass spectrometry) for trace-elements analyses.
Definition of the native copper stability and dissolution requires studies of composition,
structure, and surface (especially in fracture surface minerals) alteration of copper
minerals.
The relatively easiest available techniques to get adequate information on mineralogy,
composition, and structure are listed below.
*
Thin-polished sections
*
Polarizing microscopy
*
EPMA Electronprobe Microanalyser
*
XRD X-ray diffraction
*
AFM Atomic Force Microscopy
Thin-polished sections are used in polarizing microscopy to define the petrology of the
rocks (main minerals, accessories, secondary minerals, mineral paragenesis) at a
microscale.
24
EPMA is used to analyze quantitatively and semiquantitatively composition of minerals
also at a microscale. The detection limit of quantitative analyses may reach the order of
10 ppm. The characteristics and properties of the EPMA CAMECA SX 50 at de GTK
(Geological Survey of Finland) have been described by Johanson and Kojonen (1995).
XRD method is the only one which allows the characterization of clays and other
powdered mineral phases usually present within fracture surfaces. This method may be
also used to characterize well crystallized phases which are difficult to distinguish by
chemical analyses (because of similar composition) and/or by polarizing microscopy
(because of similar optical properties).
It is known that the surface of minerals (sulfides, oxides) may adsorb and/or reduce
metals in solution (e.g., Jean and Bancroft 1986, Hochella 1990, White and Peterson
1996, and references therein). At this respect the microtopography of mineral surfaces
may control certain mineral-water interface reactions (e.g., Dibble and Tiller 1981).
AFM is applied to determine mineral surface microtopography and atomic structure. It
can be used to imagine particles that are attached firmly to a surface (Binnig et al.
1986) and it has been recently used in a study of the adsorption of mineral colloids
(Johnson and Lenhoff 1996).
Although the main aim of this investigation is to explain the long-term behaviour of
metallic copper in a bedrock similar to that of the final repository sites, the presence of
uranium (see above) allows the application of phase selective extraction techniques
(SET). These may give information about the mode of uranium fixation in copper
sulfide. Measurements of the activity ratios (AR) from the U-238 decay series provides
information of the geochemical behaviour of uranium with respect to copper sulfide
within the last 500 000. This may indirectly give a minimum age estimation of the
existence of copper sulfide and, thus a minimum age of the end of the sulfidization
process (it is not known whether the sulfidization process is or is not actual).
Native copper, copper sulfide, smectites and calcite occurred within fracture surfaces
(Marcos 1996). Getting similar samples would allow the study of interactions among
these minerals and -especially- mineral-water interactions in an uranium-rich
environment. A study of sorption processes onto fracture surface minerals (calcite,
smectite, copper sulfide) would be of the upmost interest in modelling the interactions
and behaviour of the near-field materials in a repository environment.
The application of stable sulfur isotopes may provide information on the source of
sulfur in minerals and water. Isotope analyses for 13 C may indicate the origin
(inorganic/organic) of carbon also in minerals and groundwater.
25
4.3
croundwater sampling and analysis
4.3.1
sampling and field measurements
The possible water-sampling equipments considered are: 1) mobile laboratories (Posiva
Oy or SKB); 2) construction or modification of a new 'light' packer sampling system.
In the decision of the drilling place, accessibility by laboratory wagons was taken into
consideration, thus the option 1 is recommended, if available. An important point is that
the SKB mobile laboratory will be used at Palmottu during summer 1997. If not
urgently needed elsewhere, use of the same equipment at HyrkkoHi would be effective
in terms of transport and time requirements.
A third option is only recommended, if other equipments are not available. The 'lightweight' packer samplers available at GTK are especially designed to fit slim boreholes.
If they are used, packers in these equipments should be replaced by larger ones, and
construction would also otherwise require to be modified (e.g., valve system, pumping
principle etc.).
Parameters measured or analyzed during sampling in the field include Eh, pH, 0 2,
temperature, sulfide, iron (Fe2+/FetoJ, acidity, alkalinity, uranine. Depending on the
sampling equipment and personnel available, other analyses may also be included
according to the specifications given (e.g., Ruotsalainen et al. 1994). If possible, 'in
situ' redox and pH measurements should be made in addition to the on-line
measurements on the ground surface.
Main campaign of groundwater sampling will be carried out during autumn 1997, about
2 to 5 months after drilling. After groundwater sampling, a couple of the most
important fracture zones will be isolated by packers in such a way that later
groundwater sampling from isolated sections can be carried out.
Total amount of groundwater samples to be analyzed is uncertain: We estimate that in
a borehole (/ boreholes), with a total length of about 200 meters, there are four or less
good, water conductive fractures (/fracture zones) to be sampled. Pumping time from
one fracture would be about 2-3 weeks, pumping rates about 50 - 200 ml /min and,
consequently, total water volume extracted from one sampling section is about 1000 6000 1.
26
4.3.2 Chemical determinations
The groundwater samples are going to be analyzed for major components, trace
elements and relevant isotopes. An example of analytical packages (ICP-MS) for
groundwater cations is given in Table 2. Anions (Cl,Br,F,P04,S04 ,N03) are going to be
analyzed by ion chromatography, and alkalinity by titration. Major dissolved
components will be used as input data for water-rock interaction- and groundwater
evolution modelling. Total dissolved copper in groundwaters is normally within the
detection limits given in Table 3. For the geochemical behaviour of copper, the most
important dissolved components are the redox elements sulfur and iron.
The stable isotope ratio of water (80-18, 8D) provides information on the temperature
of precipitation, being thus the most important tool to identify possible glacial
components in groundwaters, while high tritium content of groundwater indicates
present groundwater recharge.
The stable isotope (8S-34, 80-18) content of aqueous sulphur compounds (chiefly SO/-,
H 2S and HS-) may provide information on the origin of the sulphur, and the kind of
redox processes involving sulphur. Furthermore, the 80-18 content of aqueous sulphate
possibly indicates residence time indirectly, when correlated to its residence time within
the groundwater system (Pontes 1994).
The naturally occurring radioisotope of carbon, C-14, may provide information about
flow rates and residence times of groundwater in systems with straightforward patterns
of flow and geochemical evolution (Pearson et al. 1991 ). The determination of C-14
contents in groundwater is a common tool for the determination of age-relations and
less often absolute ages within the aquifer. Ratios of stable carbon C-13 and oxygen 018 isotopes relflect the origin of minerals and of dissolved carbonate species and may
also provide insight into the sources of groundwater itself (Pearson et al. 1991). The
chlorine isotope, Cl-37, can also be used in estimating the residence time of
groundwater.
27
Table 3. The ICP-MS package (140MP) of GSF. For the given determination limits,
amount of total dissolved solids are assumed to be less than 0.2%.
-
137M
p.g/1
Ag
AI
As
B
Ba
Be
Bi
Ca
Cd
Co
Cr
Cu
Fe
K
Li
Mg
Mn
Mo
Na
Ni
Pb
Rb
Sb
Se
Si
Sr
Th
1
100
0.04
30
10
100
0.02
400
0.06
0.03
138M
139M
140M
p.gll
p.g/1
p.gll
0.01
1
0.05
0.5
0.04
0.01
1
0.05
0.5
0.04
0.1
0.03
100
0.02
0.02
0.2
0.04
30
10
0.3
100
0.02
0.03
400
0.06
0.03
0.01
0.02
0.5
600
0.1
0.02
0.02
0.01
0.02
0.1
0.01
0.1
0.05
0.5
0.04
0.1
0.03
10
0.02
0.02
0.2
0.04
5
10
0.3
0.4
0.02
0.03
15
0.06
0.03
0.01
0.02
0.5
10
0.1
0.02
0.02
0.01
0.02
0.1
100
0.02
0.2
0.04
30
10
100
0.02
0.03
400
0.06
0.03
0.02
0.5
600
n
u
V
Zn
0.1
0.1
28
4.4
Other studies
In a single hole, hydraulic conductivity and hydraulic head distribution could be
measured using the 'TVO flow-meter'. If two or more boreholes are available, crosshole tests between boreholes would give additional information on the hydraulic
connections and their continuity. After the groundwater sampling and other
measurements, some most interesting sections are going be sealed off by packers for
long-term head measurements, and later groundwater sampling. For that reason, packers
fitting the drill-hole diameter are required. If very accurate packer locations are not
needed, packers may be lowered by wire, which will reduce costs.
29
5
DISCUSSION AND CONCLUSIONS
The general progress of the proposed project was outlined in the foregoing description.
The whole succession of sampling and analyses are based on techniques frequently used
before in many different projects. Consequently, in a technical sense, the project can be
carried out within the given time table given in Table 4.
However, the most important question is if the project is able to provide
information/data on the study site as a relevant natural analogue to the behaviour of
copper canister in similar repository conditions. It is not possible to forecast the amount
and quality of samples that will be obtained. With this respect, the scientific feasibility
of the project is defined here as a succession of two levels of achievements depending
upon the quality of the samples:
1. Samples where metallic copper is not in contact with groundwater
The yield of water in the new boreholes may allow groundwater sampling from depths
corresponding to the known occurrences of metallic copper and from even deeper levels.
This would make possible to compare 1) groundwater conditions in Hyrkkola to those
studied in the Posiva's site characterization program and 2) -through an
extrapolation- the geochemical data obtained to the thermodynamic data used in
modelling corrosion of copper canisters.
2. Samples where metallic copper is in contact with groundwater
Even if the first level of information defined above is considered as a notable result
with respect to the needs of performance assessment of the nuclear waste disposal, the
research project is strongly focused on obtaining direct observations of the metallic
copper surfaces exposed to the groundwater. So far, this type of information has not
been available, not in microscopic scale, but even less on atomic level studied by AFM.
The results may be thus of great scientific importance, supporting the status of nuclear
waste disposal programs within hydrogeochemical research in deep bedrock.
Getting insight of the time scale of the processes (e.g., sulfidization) and evolution of
groundwater is the most challenging part of the work planned. The use of isotopic tools
similar to those described in section 4.3.2 are currently planned within the frames of
many paleohydrogeological research programs. Obtaining information on the time scale
of the processes would be of the upmost profit of the study.
~
~
t'D
~
~
-98
-97
§'
(!)
May I Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb I Mar
Apr
May
.-+
~
1--'
(!)
Project preparation
0
H)
g.
Planning and
preparation of drilling
(!)
"'d
1-1
t.2.
(!)
Drilling and
sampling
Drill core studies
Groundwater sampling
Groundwater analyses
Isotope studies
(Rock & Groundwater)
Analyses of results
and final report
(")
.-+
....................
...................................
...................................
...................................
...................................
.................................................................
w
0
31
There are only a few countries in the world, which use the corrosion-resistant copper
canister in their spent-fuel disposal concept. Consequently, there is very little
experimental data and observations on the behaviour of metallic copper in the reducing
conditions of the deep bedrock. As with the other components of the multibarrier
system, we have to be able to show that the theoretical calculations on the stability of
copper are in accordance with direct observations. The appropriate time scale and
relevant physicochemical conditions for such observations are most easily met by
studying natural analogs. A straightforward benefit of the project is the ability to
demonstrate the long-term stability of metallic copper within geological time scales and
hydrogeochemical conditions of deep bedrock. This approach is most useful in public
acceptance, that is, the demonstration of the stability of copper to non-specialists.
Detailed studies of the surfaces of native copper are also expected to bring more
information on the actual corrosion processes of metallic copper. For the performance
assessment of the copper canister, the primary distinction is between the corrosion
concept: anoxic-sulfidic corrosion producing cuprous sulfide or mildly oxic corrosion
producing cuprous oxide. The present Finnish concept (e.g., Vieno et al. 1992, Ahonen
1995) considers the sulfidic corrosion as the main process in considering the long-term
behaviour of copper in the deep bedrock. However, after the closure of the repository,
a short period of partly oxygenated conditions may prevail. Deglaciation of continental
ice sheet may also cause transient intrusion of oxygen-rich water into fracture zones of
the bedrock. Results from HyrkkoHi study may give us information on the relative
importance of these different modes of corrosion.
Due to the thinner canister wall of copper canister together with the assumed lack of
sulfide in the disposal environment, oxic forms of reaction products are considered as
prevalent in the Canadian concept (e.g., King et al. 1992). It is also known that the
stress assist cracking corrosion in the presence of strong electron acceptors (electrolytic
cell with nitrite) (e.g., Hietanen et al. 1996).
The study of HyrkkoHi native copper may allow us to
1)
determine the main corrosion products of metallic copper (if any) in conditions
probably similar to the conditions of potential waste-disposal sites in Finland
and Sweden,
2)
study the extent of copper corrosion processes to obtain detailed information on
the mechanism/s of corrosion, and
3)
get information on the time scale of the processes.
4)
get information on the sorption properties of engineered barrier corrosion
products
32
6
REFERENCES
Ahonen L., 1995. Chemical stability of copper canisters in deep repository. Nuclear
Waste Commission of Finnish Power Companies, Report YJT-95-19.
American Small Business Computers, Inc., 1992. Design Cad 3-D, Version 4.0.
Reference manual, 464 p.
Binnig G., Quate C., and Gerber Ch., 1986. Atomic force microscope. Phys. Rev. Lett.
56, p. 930 - 933.
Dibble W.E. Jr. and Tiller, W.A., 1981. Non-equilibrium water/rock interactions - I.
Model for interface-controlled reactions. Geochim. et Cosmochim. Acta 45, p. 79 - 92.
Engman U., and Hermansson H.-P., 1994. Korrosion av kopparmaterial for inkapsling
av radioaktivt avfall - En litteraturstudie. SKI Rapport 94:6. Swedish Nuclear Power
Inspectorate.
Fontes J.Ch., 1994. Isotope palaeohydrology and prediction of long-term repository
behaviour. Terra Nova, 6, p. 20 - 36.
GemCom Services Inc., 1991. Geomodel User Manual, Software for Geological
Modelling. Vancouver, Canada.
GemCom Services Inc., 1992. PC-XPLOR User Manual, PC-XPLOR Version 2.00,
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Hallberg, R.O., Ostlund P., and Wadsten T., 1988. Inferences from a corrosion study of
a bronze cannon, applied to high level nuclear waste disposal. Applied Geochemistry,
3, p. 273 - 280.
Hietanen S., Ehrnsten U., and Saario T., 1996. Environmentally assisted cracking
behaviour of copper in simulated groundwater. STUK-YTO-TR 105. Finnish Centre for
Radiation and Nuclear Safety.
Hochella M.F., 1990. Atomic structure, microtopography, composition, and reactivity of
mineral surfaces. In Mineral-Water Interface Geochemistry (Eds. M.F. Hochella Jr. and
A.F. White). Amer. Mineral. Soc., Rev. in Miner. 23, p. 87 - 132.
Hyyppa J. and Juntunen R., 1983. Nummi-Pusulan kunnan Hyrkkolan kylan kaivovesien
uraani- ja radonpitoisuuden tutkimukset v. 1982. Julkaisematon tutkimusraportti
13.5.3.013.
Jean G. and Bancroft G.M., 1986. Heavy metal adsorption by sulphide mineral surfaces.
Geochim. et Cosmochim. Acta 50, p. 1455 - 1463.
Johanson B. and Kojonen K., 1995. Improved electron probe microanalyses services at
Geological Survey of Finland. Geological Survey of Finland, Special Paper 20, 181-184.
33
Johnson C.A. and Lenhoff A.M., 1996. Adsorption of charged latex particles on mica
studied by atomic force microscopy. J. Colloid and Interf. Sci., 179, p. 587 - 599.
King F., Litke C.D., and Ryan S.R., 1992. General corrosion of copper nuclear waste
containers. Corrosion 92. The NACE Annual Conference and Corrosion Show, paper
119.
Kuivamaki A, Paananen M. and Kurimo M., 1991. Structural modelling of bedrock
around the Palmottu U-deposit. Geological Survey of Finland, Nuclear Waste Disposal
Research, report YST -72, 30 p.
Latvalahti, U., 1979. Cu-Zn-Pb ores in the Aijala-Orijarvi area, southwest Finland.
Econ. Geol. 74, pp. 1035 - 1059.
Marcos N., 1996. The Hyrkkola native copper mineralization as a natural analogue for
copper canisters. Report Posiva-96-15, Posiva Oy, Helsinki
Miller W., Alexander R., Chapman N., McKinley I., and Smellie J., 1994. Natural
Analogue Studies in the Geological Disposal of Radioactive Wastes. NAGRA, Technical
Report 93-03, January 1994.
Makela, U., 1989. Geological and geochemical environments of Precambrian sulphide
deposits in southwestern Finland. Ann. Acad. Sci. Fenn., Ser. A, No. 151, 102 p.
Nenonen K. and Hakala P., 1983. Malminetsintaa palvelevat maaperatutkimukset
Nummi-Pusulan Hyrkkolassa KL. 2024 10. Geological Survey, unpublished research
report P/3.2.041.
Pearson F.J. Jr., Balderer W., Loosli H.H., Lehmann B.E., Matter A.,Peters Tj.,
Schmassmann H., and Gautschi A., 1991. Applied isotope hydrogeology- a case study
in northern Swithzerland. Studies in Environmental Science 43, Elsevier, Amsterdam,
439 p.
Ploegsma, M., 1989. Shear zones in the West Uusimaa area, SW Finland. Doctoral
thesis, Vrije Univesiteit te Amsterdam, 134 p.
Ruotsalainen, P. (toim.) 1994. TVO:n vesinaytteenoton kenttatyoohje. Work-report
PATU-94-28. Teollisuuden Voima.
Raisanen E., 1986. Uraniferous granitic veins in the Svecofennian schist belt in NummiPusula, southern Finland. Technical Commitee Meeting on Uranium deposits in
Magmatic and Metamorphic rocks. Report IAEA-TC-571, 37-44.
Schreurs, J. & Westra, L., 1986. The thermotectonic evolution of a Proterozoic, low
pressure granulite dome, West Uusimaa, SW Finland. Contr. Min. Petrol. 93, pp.263 250.
34
Schwartz M.O., 1996. Native Copper Deposits and the Disposal of High-Level Waste.
International Geology Review, 38, p. 33 - 44.
Simonen, A. 1956. Geological map of Finland 1:100 000, sheet 2024 Somero,
explanation to the map of rocks (in Finnish, summary in English). Geological Survey
of Finland, 30 p.
White A.F. and Peterson M.F., 1996. Reduction of aqueous transition metal species on
the surfaces of Fe(II)-containing oxides. Geochim. et Cosmochim. Acta 60, p. 3799 3814.
Vieno T., Hautojarvi A., Koskinen L., and Nordman H., 1992. TV0-92 safety analysis
of spent fuel disposal. Nuclear Waste Commission of Finnish Power Companies, Report
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report of investigations M19/2023/-84/1!60, 18 p.

Research plan for field studies at the Hyrkkiil8 native

Transcription

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