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Exploration and Mining in Greenland
GEOLOGY AND ORE
No. 2
The Black Angel lead-zinc
mine at Maarmorilik in
West Greenland
The Black Angel lead-zinc
mine at Maarmorilik in
West Greenland
The Black Angel mine took its name
from a pelite outcrop that forms a
dark angel-like figure on a precipitous
cliff face of marble above Affarlikas-
saa fjord. The mineralised zone actu-
ally crops out just above the angel
figure about 700 m above fjord level.
The 1100 m high Angel mountain is
situated at the margin of the Green-
land ice cap at 71°N lat. on the west
coast of Greenland, about 500 km
north of the Arctic Circle, where there
is two months of winter darkness.
The peninsula across the fjord housed
the mining camp, concentrator and all
services and received its name
Maarmorilik from a former marble
quarry situated there from the 1930s.
The only access to the mine from
these facilities was by two aerial
tramways.
The Black Angel deposit comprised
ten ore bodies totalling 13.6 million
tons grading 12.3% Zn, 4.0% Pb and
29 ppm Ag. Of these 11.2 million tons
were extracted in the period 197390.
The mining operations ceased when
the extractable ore reserves were
exhausted, leaving 2.4 million tons of
ore tied up in pillars and other areas
inaccessible to mining.
2
Greenland
Canada
Inland
Ice
Hudson
Bay
Maarmorilik
SUPERIOR
CRATON
NORTH
ATLANTIC
CRATON
Foxe
-
Rinkian
belt
500 km
Lower Proterozoic
supracrustal rocks
Middle Proterozoic-Tertiary
platform rocks
Archaean
Hudsonian (including
reworked Archaean)
Pre-drift map of West Greenland and NE Canada showing the Foxe-Rinkian mobile belt and
Maarmorilik. Modified from Grocott & Pulvertaft (1990).
View from north-west of the Angel mountain with the Greenland Inland Ice in the background. The former mining town of Maarmorilik was
situated on the peninsula to the right. Summer 1992.
GEOLOGY AND ORE 2 / 2003
The Black Angel lead-zinc mine
at Maarmorilik in West Greenland
Regional geology
The ores are hosted in the Mârmorilik
Formation of the Palaeoproterozoic Karrat
Group. This Group belongs to the Foxe
Rinkian mobile belt of NE Canada and
central West Greenland, which constitutes
a component of the Trans-Hudson Orogen
of North America. In Greenland, exposures
of the Karrat Group are known over a
northsouth distance of c. 550 km cover-
ing some 10,000 km
2
. The Group, that
rests unconformably on an Archaean
gneiss complex, is intruded by a major
1860 Ma syn-tectonic granite complex
and is overlain by CretaceousTertiary sed-
iments and volcanics. The Karrat Group,
several kilometres thick, is composed of
lower shelf units of carbonates and
quartzites, and an upper unit of deep-
water turbidites and minor volcanic rocks.
The basement and the cover sequence
were subjected to several phases of strong
folding and thrusting during the
Hudsonian orogenesis and variably affect-
ed by regional metamorphism.
The Mârmorilik Formation consists of cal-
citic and dolomitic marbles with a basal
quartzitic unit and intercalations of anhy-
drite-bearing marbles and semipelitic
schists. The formation is believed to have
been deposited on a carbonate shelf in an
epicontinental marginal basin c. 2 Ga ago.
In the mine area, where the formation has
been tectonically thickened to c. 1000 m,
three main phases of folding and thrust-
ing have been distinguished, and meta-
morphism reached upper greenschist
facies.
Mineralisation and ore
Carbonate-hosted lead-zinc mineralisation
is common in the Mârmorilik Formation
and in the mine area stratabound sulphide
mineralisation occurs at various levels. The
main ore bodies are located 600700 m
a.s.l. in the upper part of the sequence
which is dominated by calcitic marble,
whereas the satellite ores of Nunngarut to
the south are hosted in the lower part of
the sequence dominated by dolomite mar-
ble. The distribution of ore bodies is con-
trolled by a major z-fold with a 070°-strik-
ing near-horizontal axis. The ore forms
flat-lying, highly deformed, massive lenses
up to 30 m thick, of which ten reach eco-
3
GEOLOGY AND ORE 2 / 2003
T H E B L A C K A N G E L L E A D - Z I N C M I N E A T M A A R M O R I L I K
Inland Ice
Qaamarujuk
Maarmorilik
Uummannaq
Nuussuaq
Nunngarut 2
Angel
I South
I
V 16
Cover
Banana
Tributary
Nunngarut 1
Deep
Ice
Map
500 m
500 m
500 m
A
ffa
rlik
as
sa
a
2
1
3
4
25 km
1 km
71
°
07´N
71
°
N
51
°
15´W
51
°
15´W
52
°
W
Map of the Maarmorilik area with ore bod-
ies shown in red. Stars in inset map show
main prospects of Black Angel type; the
cross marks a shale-hosted zinc prospect.
Pb
concentrate
1000 t
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1996
Total
8
37
32
38
39
42
45
42
38
37
31
26
26
24
30
34
36
25
-
590
46
168
153
143
132
148
151
151
140
141
136
122
119
105
120
136
129
87
-
2,327
-
336
429
478
387
332
592
520
683
653
754
723
542
456
440
779
843
507
-
9,454
-
1
6
11
11
2
11
22
63
37
56
33
3
-32
1
59
157
99
16
556
-4
76
91
97
33
16
128
85
109
71
79
71
-231
55
53
149
184
92
-
1,154
Zn
concentrate
1000 t
Gross sales
mill. DKK
Taxes
mill. DKK
Net earnings
mill. DKK
Key economic figures for the Black Angel mine
nomic size and were mined. The massive
ore consists of pyrite, sphalerite and gale-
na, with abundant rotated marble frag-
ments and quartz inclusions. The main
accessory ore minerals are pyrrhotite, chal-
copyrite, tennantite and arsenopyrite.
Cherty horizons and disseminated
graphite are quite common in the wall
rocks whereas minor fluorite and baryte
are restricted to a few of the ore bodies.
Various ore tectonites have been distin-
guished massive ore, banded ore, por-
phyroclastic ore or "buck shot ore" and
remobilised ore.
The sulphides are strongly tectonised and
metamorphosed and the origin of the ores
is uncertain; their present distribution is
structurally controlled. It is perhaps most
likely that the ores have been formed by
sedimentary-exhalative processes on the
sea floor (SEDEX-type) but they could also
have formed at a later stage (Mississippi
Valley-type).
Sphalerite-galena-pyrite occurrences of the
Black Angel type are known from marble
outcrops at three localities south of Maar-
morilik. It appears that this type of sul-
phide deposit only occur in areas of
intense folding and major structural thick-
ening of the marbles.
Zinc mineralisation is also known from the
clastic metasediments of the Karrat
Group. At one locality north of Maar-
morilik, stratabound sphalerite-galena-
pyrrhotite mineralisation occurs over a
strike-length of some 9 km near the base
of the turbidite sequence. The clastic rocks
also have a potential for epigenetic `tur-
biditehosted gold deposits'.
History of the mine
Sulphide samples leading to the discovery
of the Black Angel deposit were found in
connection with marble quarrying in the
1930s and investigated by Danish geolo-
4
Elev. 600 m
Elev. 0 m
Affarlikassaa
1.7 km
Elev. 1000 m
A simplified cross-section through the Black Angel mine
Angel zone
Fine
e ore bin
The mill
Th
Crusher
Maarmorilik
W
GEOLOGY AND ORE 2 / 2003
T H E B L A C K A N G E L L E A D - Z I N C M I N E A T M A A R M O R I L I K
gists in the 1930s and 1940s. Commercial
investigations including diamond drilling
were carried out in the 1960s by a syndi-
cate led by Cominco Ltd. of Canada. In
1971 the Danish mining company Green-
ex A/S (established in 1964 and 62.5%
owned by Cominco Ltd. through the sub-
sidiary Vestgron Mines Ltd.) obtained a
25-year exploitation concession. Financial
terms were favourable at that time, with
only a resource tax of yearly earnings to
be paid after recovery of all pre-produc-
tion costs and capital investments. The
investment of c. 333 mill. DKK had been
recovered in 1977, after which the com-
pany started to pay concession fees.
Underground exploration in 197172 indi-
cated a probable ore reserve of 4.1 million
tons grading 15.0% Zn, 5.0% Pb and 28
ppm Ag. Based on this and after a hectic
construction period of only 15 months,
production started in 1973. During the
mine's 17-year lifespan, it was possible to
more than triple the original minable
reserves. In 1985 a major operating loss
was incurred, and due to growing finan-
cial losses and dwindling ore reserves,
Cominco scheduled Black Angel mine for
closure in early 1986. Boliden Mineral AB
took over Greenex from Cominco in mid-
1986. Boliden managed to keep the mine
in operation and ensure sufficient mill
throughput for profitable operation until
mid-1990. Boliden cut operation costs,
which peaked at about 1,700 DDK/t in
1985 by about 30% to 1,200 DDK/t.
Among other things, personnel were
reduced from 335 at the end of 1984 to
around 250 in late 1987. Greenex was liq-
uidated in 1995.
Infrastructure and personnel
The Maarmorilik townsite comprised a
storage hall for stockpiles, workshops,
harbour and shipping facilities, offices,
residences, dining hall, heliport and
hangar, as well as medical facilities.
5
Black Angel mountain
Banana zone
I zone
Cover zone
Inland Ice
4.0 km
E
Massive ore
Pelite
Grey banded marble
White/light grey banded marble
LEGEND
GEOLOGY AND ORE 2 / 2003
T H E B L A C K A N G E L L E A D - Z I N C M I N E A T M A A R M O R I L I K
A simplified cross-section through the Black Angel mine. Not to scale.
Recreational facilities included a radio/TV
station, library, sports hall, post office,
recreation centre and guest apartments.
An 8.4-MW diesel generator station pro-
vided all the power needed for the mine's
operations and the community. By desali-
nating the fjord water through use of
waste heat from the diesels, the power
plant also produced all the fresh water
required. The saline-enriched water from
the desalination plant was used as drilling
fluid in the mine; strong brine would not
freeze when drilling in permafrost. The
brine for drilling had to be transported in
tanks up to the mine via the aerial
tramway, as had all other equipment.
Supplies had to be shipped in and concen-
trate shipped out during the 6 months
ice-free period from June to November.
Personnel were ferried by helicopter
between the mine and the nearest airport
at Ilulissat, 200 km to the south.
The Black Angel mine provided employ-
ment opportunities and was important to
the local economy. Of the c. 350 employ-
ees, up to 44% were Greenlanders, the
rest mainly Danes and Swedes. The em-
ployees worked a 10-hour shift, with 2
shifts a day, six days a week. Four working
months at the mine earned one month's
vacation, travel included.
When mining was discontinued, Greenex
undertook in 199091 an extensive clean-
up, partly of buildings, plant, installations
etc. and partly targeting the sources of
heavy-metal contamination in the area.
Final abandonment involved the removal
of all surface structures (except two) and
the cable ways. Very little infrastructure
was removed from the mine.
Exploration in the mine area
In the period 196685, 17 major surface
drilling programs were conducted around
Maarmorilik and a total of 160,000 m was
drilled in 400 holes. Most of the drilling
was on top of the Angel mountain where
it was performed systematically in a grid
along the 070° corridor hosting the ores.
Much of this was through the ice cap, so
that 200300 m of ice had to be pene-
trated and then several hundred metres of
rock to intersect the target areas. New ore
bodies located by surface drilling were
investigated further by underground
drilling. Primary exploration drilling was
also accomplished underground, thus con-
tinually adding new tonnage to the ore
reserves.
High-grade ore intersections below the ice
cap were encountered in three areas. Only
the westernmost of these, the Deep Ice
zone, was reached by primary develop-
ment and mined, whereas the two east-
ernmost targets remain. This was partly
due to delays created by water inflow due
to the lack of permafrost below the ice
cap.
Immediately south of the mine area, sev-
eral lead-zinc prospects of Black Angel
6
Mining town seen from the mine portal. Summer 1990.
GEOLOGY AND ORE 2 / 2003
T H E B L A C K A N G E L L E A D - Z I N C M I N E A T M A A R M O R I L I K
type exist, and farther away, lead-zinc
prospects of the same type occur in three
areas. Some of these were drill tested but
all were rejected as viable prospects by
Greenex. However, the zinc prospects in
the turbidite basin north of Maarmorilik
were found after the mine closure and
never drilled.
Mining and ore treatment
The main mining equipment was electro-
hydraulic 2 and 3 boom jumbos, front-end
loaders (scooptrams) and trucks, and the
mine housed an underground workshop
for repair and maintenance. After drilling
by hydraulic jumbos and blasting, the bro-
ken ore was hauled by truck to ore passes
and then by locomotive haulage to the
primary crusher bin just inside the
tramway portal. Parts of the Angel zone
near the portal were declared off limits to
mining to protect major access and trans-
port routes in this area from possible dam-
age from rock instability. The crushed ore
was skipped across the fjord to the ore
dressing plant by an aerial tramway with a
free span of 1500 m. The tramway had a
capacity of 12 skips per hour; skip capaci-
ty was 10 tons. One skip was fitted with a
cabin to transport personnel. There was a
second, smaller tramway for transporta-
tion of material. Ore from Nunngarut was
7
GEOLOGY AND ORE 2 / 2003
T H E B L A C K A N G E L L E A D - Z I N C M I N E A T M A A R M O R I L I K
Car on foot-wall ramp in marble below mined-out stopes in ore dipping to the left.
Sketch of thin irregular ore which must be
mined selectively.
0
10
20
30
40
50
60
70
80
90
Year
10.000 t
Pb%
Zn%
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
Annual ore
production
at the Black
Angel mine.
trucked directly to a crusher in
Maarmorilik.
The concentrating process was conven-
tional selective flotation of galena and
sphalerite using sea water. In most years
the recovery was c. 96% for zinc, 90%
for lead and 75% for silver. Annual pro-
duction averaged 135,000 tons of 57.6%
zinc concentrate and 35,000 tons of
69.7% lead, 420 ppm silver concentrate.
Tailings were discarded through a pipeline
to the bottom of the adjacent Affarlikas-
saa fjord. The concentrate was stored
under cover and shipped to West
European smelters, normally by three ship-
ments between June and November.
For the ore reserve calculations comput-
erised from the early 1980s a diluted
cut-off grade of 8% combined lead and
zinc was used. The ore was mainly mined
by the room-and-pillar method; only
smaller steep ore bodies were mined by
cut-and-fill methods. In thin parts of the
ore, selective mining (resuing) was prac-
tised. The full face was drilled over, keep-
ing the ore horizon in the top of the face.
The lower part of the face containing the
8
in 1000 t
Angel
Cover
Tributary
I
Banana
Nunngarut 1
Deep Ice
Nunngarut 2
I South
V 16
Total
6,645
3,992
767
684
450
347
316
197
119
36
13,557
4.8
2.8
2.0
4.6
2.9
3.8
5.5
3.1
4.3
1.9
4.0
14.2
10.5
9.1
12.3
8.3
8.7
14.8
7.2
11.1
5.3
12.3
5,283
3,343
683
622
335
327
312
150
112
28
11,196
5.0
3.0
2.0
4.7
3.2
3.8
5.5
3.2
4.4
2.0
4.1
Pb%
Zn%
in 1000 t
Pb%
14.6
11.0
9.2
12.7
9.1
8.8
14.9
7.5
11.2
5.4
12.6
83
84
89
91
73
94
99
76
95
79
83
85
88
90
94
82
95
99
79
95
81
85
Zn%
Ore
Metal
Tonnage
Production
Recovery %
Ore zone
Tonnage and production of individual ore bodies
of the Black Angel mine
GEOLOGY AND ORE 2 / 2003
T H E B L A C K A N G E L L E A D - Z I N C M I N E A T M A A R M O R I L I K
Maarmorilik after the removal of the mining town. Summer 1997.
View of the mining town and the Angel
mountain from the west. Summer 1985.
waste was blasted and mucked out first.
The upper ore section was then mined.
Ore bands down to 0.4 m thick were
mined by this method.
Remnant mining guided by a careful
registration of metal contents in the pillars
aiming at maximal metal recovery and
supervised by an extensive rock mechanics
programme led to a high metal extrac-
tion rate of 85%. In one section of the
Angel zone, the stopes were totally back-
filled with waste and a number of high-
grade pillars were recovered by long hole
mining from drifts underneath the ore
horizon.
All ten ore zones, except the Deep Ice
zone, are in permafrost. On the whole,
the permafost proved to be an asset for
mine stability and it contributed to the
high extraction rate. Close to the surface
the rock temperature is minus 4°C and
this rises by 1°C per 150 m from surface.
However, under the ice cap, the tempera-
ture rises more rapidly so that the eastern
part of the mine is not in permafrost
hence water flows in from fissures in the
marble. During development of the access
ramp to the Deep Ice zone, drifting was
stopped in 1984 for more than a year
because of high water inflow. It was final-
ly continued through the water-bearing
zone under cover of grout injection and
draining of the water.
Pollution and environmental
monitoring
After the first few years of mining, pollu-
tion was found to be a bigger problem
than anticipated. Increasing amounts of
dissolved lead, zinc and cadmium were
measured in the fjord water around
Maarmorilik. A comprehensive monitoring
of heavy metals in the biota showed that
lead pollution of blue mussels and sea-
weed in the intertidal zone of the coastal
areas near Maarmorilik was the most seri-
ous problem. As a result, the authorities
requested Greenex to improve the envi-
ronmental situation, the main culprits of
the pollution being tailings and waste
dumps.
The tailings were discharged at a depth of
30 m through a pipeline, from where they
settled on the bottom of the Affarlikassaa
fjord at 5060 m.
A number of measures were undertaken,
and from 1978 to 1985 lead content of
the tailings fell from 0.44% to 0.15%,
zinc content from 1.10% to 0.23% and
cadmium content from 57 to 14 ppm.
9
GEOLOGY AND ORE 2 / 2003
T H E B L A C K A N G E L L E A D - Z I N C M I N E A T M A A R M O R I L I K
Typical face to be mined selectively: ore on top of white marble.
"Buck shot ore" with marble rafts left in pillar.
Four waste dumps totalling 23 million
tons with 0.10.8% Pb and 0.32.3% Zn
had been disposed outside the mine in its
first 10 years of operation. One of these
dumps of c. 400,000 tons reached into
the tidal zone, and the highest lead- and
zinc values in seaweed and mussels
occurred in this area. After mine closure
this dump was removed and partly placed
on the bottom of the Affarlikassaa fjord
and partly in the former concentrate stor-
age.
Rib pillar with high
grade banded ore.
GEOLOGY AND ORE 2 / 2003
T H E B L A C K A N G E L L E A D - Z I N C M I N E A T M A A R M O R I L I K
Scooptram shifting broken rock.
Waste dump rea-
ching from 345 m
a.s.l. into the fjord
on north side of
the Angel moun-
tain, summer
1989. The ore
horizon is seen just
above the dump
hole (arrow) in the
uppermost part of
the 900 m high
cliff. The dump
was removed after
mine closure.
10
GEOLOGY AND ORE 2 / 2003
T H E B L A C K A N G E L L E A D - Z I N C M I N E A T M A A R M O R I L I K
Prior to abandonment, an environmental
agreement was in place to ensure the
ongoing monitoring of the fjords around
Maarmorilik by the National
Environmental Research Institute (NERI).
Thus, since closure the environment
around the site has been monitored annu-
ally by analysing for lead and zinc in sea
water, lichens, seaweed and marine ani-
mals. As anticipated, these studies show a
marked decline in heavy metal concentra-
tions compared to earlier. Environmental
monitoring will be continued until 2005.
Resumption of mining activity?
In spring 1997, Canadian company
Platinova A/S was granted an exploration
licence for the Maarmorilik area in order
to examine the possibilities for re-opening
the mine. The Platinova plan was based
on mining about half of the remaining
zinc from the highest value pillars in the
Angel and Cover zones (800,000 tons
averaging 14% Zn and 4.5% Pb). The ore
was to be crushed on site and shipped by
bulk ocean carrier during three shipping
seasons to a concentrator for custom
milling.
During a site visit in 1997, the mine was
found to be completely dry with few signs
of loose rock falling from the back in
either stoping areas or travel ways.
Measurements of previously established
rock mechanical control points revealed
no detectable ground movement since
shutdown in 1990. Much of the equip-
ment, including crushing facilities, was in
excellent condition with virtually no signs
of rust. In January 1998, however, due to
low zinc prices Platinova gave up the proj-
ect and the company has since aban-
doned its license.
The future of the 'Black Angel'
At mine closure, Greenex deposited
important geological records at the
Geological Survey of Greenland,
Copenhagen now the Geological
Survey of Denmark and Greenland
(GEUS). This included data files comprising
the ore reserves data base, geological sec-
tions and mine maps, a collection of typi-
cal ore specimens and 23 km of drill core.
In 1999, the cores were relocated at the
Bureau of Minerals and Petrolems's drill
core archive in Kangerlussuaq, West
Greenland. A complete set of surface
exploration reports was already housed at
the Survey. The collections in Denmark
and Greenland make it possible to contin-
ue studies of the Black Angel ores with
the possibility of gaining new understand-
ing about the distribution of possible addi-
tional ore in the area.
The existence of an additional ore poten-
tial in the mine area is indicated by ore
grade intersections known from surface
drillings in two areas to the east. It is to
be hoped that research in the Black Angel
records and continued field exploration of
the Mârmorilik Formation and the Karrat
Group will ultimately result in renewed
mining.
11
Mining town seen from the cable car with ore skip in the foreground. Spring 1986.
Key references
Alm, L., Christensen, K. & Ekenberg, R. 1987:
Room and pillar mining in Maarmorilik, Greenland.
In: Almgren, G., Berg, I. & Matikainen, R. (eds):
Improvement of mine productivity and overall econ-
omy by modern technology, 895904. Rotterdam:
A. A. Balkema.
Garde, A.A. 1978: The Lower Proterozoic
Marmorilik Formation, east of Mârmorilik, West
Greenland. Meddelelser om Grønland 200(3),
71 pp.
Grocott, J. & Pulvertaft, T.C.R. 1990: The
Early Proterozoic Rinkian Belt of central West
Greenland. In: Lewry, J.F. & Stauffer, M.R. (eds):
The Early Proterozoic Trans-Hudson Orogen of
North America. Geological Association of Cana-
da Special Paper 37, 443463.
Krauland, N. & Söder, P.E. 1987: Determining
pillar strength from pillar failure observation.
Engineering and Mining Journal 188, 3440.
Pedersen, F.D. 1980: Remobilization of the
massive sulphide ore of the Black Angel mine,
central West Greenland. Economic Geology 75,
10221041.
Pedersen, F.D. 1981: Polyphase deformation of
the massive sulphide ore of the Black Angel
mine, central West Greenland. Mineralium
Deposita 16, 157176.
Thomassen, B. 1991: The Black Angel lead-zinc
mine 197390. Rapport Grønlands Geologiske
Undersøgelse 152, 4650.
Thomassen, B. 1992: The gold and base metal
potential of the Lower Proterozoic Karrat
Group, West Greenland. Rapport Grønlands
Geologiske Undersøgelse 155, 5766.
Wyllie, R.J.M. 1988: Boliden coaxes a few
more years out of Greenland's Black Angel
mine. Engineering and Mining Journal 189(2),
2633.
12
GEOLOGY AND ORE 2 / 2003
Greenland Resources A/S
Vandsøvej 5
P.O. Box 821
DK-3900 Nuuk
Greenland
Tel: (+299) 32 79 13
Fax.: (+299) 32 79 14
E-mail: gras@greennet.gl
Internet: www.resources.gl
Bureau of Minerals and Petroleum
(BMP)
Government of Greenland
P.O. Box 930
DK-3900 Nuuk
Greenland
Tel: (+299) 34 68 00
Fax.: (+299) 32 43 02
E-mail: bmp@gh.gl
Internet: www.bmp.gl
Author:
Bjørn Thomassen, GEUS
Editor:
Karsten Secher, GEUS
Graphic Production:
Annabeth Andersen, GEUS
Printed:
April 2003
Printers:
Schultz grafisk
Geological Survey of Denmark
and Greenland (GEUS)
Øster Voldgade 10
DK-1350 Copenhagen K
Denmark
Tel: (+45) 38 14 20 00
Fax.: (+45) 38 14 20 50
E-mail: geus@geus.dk
Internet: www.geus.dk
Front cover photograph:
The Black Angel mountain with mine portals and
angel figure, with traditional Greenland dog
sledges in the foreground. Spring 1980.
Depot of drill cores from surface exploration on top of the Angle mountain. Summer 1989.
