INVENTORY FILE NO.
NAME OF PROPERTY
1993 Black Hawk Mining Inc.
2000 - 95 Wellington St.
Toronto, ON M5J 2N7
The following description of the Farley Lake deposit (not to be
confused with the Farley shaft of the nearby “A” mine. See: Mind No. 636)
is based mostly on personal communication with Neil Briggs of Manitoba Mineral
Resources Ltd. (MMR) and Ted Baumgartner of Hudson Bay Exploration and
Wasekwan Group iron formation, argillite and andesite to
basalt flows underlie the area. These rocks are considered to represent the
eastern continuation of the Agassiz Metallotect. A small quartz diorite plug
intrudes these rocks to the west of Farley Lake.
The iron formation in
the Farley Lake area is 6 km long by 600 m wide (Milligan, 1960, Map No.
3) and is predominantly composed of an oxide facies iron formation that is
intercalated with clastic sediments (Dahlstrom, 1949; Milligan, 1960). The oxide
facies iron formation, that outcrops west of Gordon Lake, consists of laminae of
hematite and chert ranging from less than 5 cm up to 15 cm in width (Stanton,
Between Gordon and Farley Lake, the oxide facies iron formation
consists of interbedded laminae of magnetite, chert and layers of chlorite,
amphibole, minor silica and disseminated magnetite. The oxide facies iron
formation hosts several zones of gold mineralization. They occur as lens-shaped
deposits within and subparallel to alteration zones characterized by
silicification, chloritization and sulphidization; both the deposits and the
alteration zones are oblique to layering. The gold and sulphide bearing iron
formation consists of interbedded pyrrhotite/magnetite and chert laminae. Minor
amounts of pyrite and silicate minerals are also present. The proportion of
pyrrhotite in individual pyrrhotite/magnetite laminae ranges from less than 5%
up to 90% and contains small isolated grains of gold in the cavities of the
silicate matrix and within pyrrhotite and magnetite grains (Manitoba Mineral
Resources, internal report). Traces of gold and sulphides also occur in quartz
veins within iron formation, argillite, mafic volcanics and quartz
Exploration has outlined three zones of gold mineralization, the
Wendy, South and East zones. The Wendy Zone and East Zone have combined
geological reserves of 635,000 tonnes averaging 6.86g/tonne (0.20oz/tonne) gold
(Northern Miner, January 19, 1987, p. 13). The South Zone contains an estimated
363,000 tonnes grading 4.80 g/tonne (0.14 oz/ton) gold.
MMR and HBED consider
the deposits epigenetic and similar in genesis to iron formation-hosted gold
deposits at Water Tank Hill and Nevoria, Western Australia. It has been proposed
that the deposits are formed in these areas by selective replacement of oxide
facies banded iron formation by gold and sulphur bearing fluids (Phillips et
al., 1984). Fyon et al. (1983) proposed a similar genesis for the Carshaw and
Malga gold deposits at Timmins, Ontario and suggested that fluid ingress was
along fractures and faults in the iron formation. Evidence supporting an
epigenetic model for formation of the Farley Lake deposit is:
abrupt change from barren oxide facies iron formation to gold and sulphide
bearing iron formation,
2) the deposits and the surrounding alteration zone
crosscut stratigraphy, and
3) the concentration of gold relative to base
metals in the deposit.
MINERALS OR PRODUCTS OF VALUE
EXPLORATION AND DEVELOPMENT
Sherritt Gordon Mines Limited staked the area as the Lind claims in
1945. Mapping in the area discovered gold in frost heaved boulders at the west
end of Farley Lake (Milligan, 1960).
In 1947, drilling carried out by
Sherritt, on the Lind showing and in the Pot Hole Lake-Pump Lake area,
intersected two gold-bearing zones that assayed up to 14.0g/tonne (0.41oz/ton)
gold (Manitoba Mines Branch, Non-confidential assessment files 91041, 91836).
After this initial drilling, the claims were apparently inactive until they
lapsed in 1976.
HBED staked the property in 1977 and from 1978 to 1983, HBED,
as operator, carried out linecutting, HLEM surveys and diamond drilling in the
search for base metals. MMR, as operator in a joint venture agreement with HBED,
carried out extensive exploration programs from 1983 to 1989. In 1986,
widespread gold mineralization was discovered in three zones, two of which was
considered amenable to open pit mining (Manitoba Mineral Resources, News release
to the Northern Miner, January 1987). In total, 15 250 m of drilling was carried
In 1989, a feasibility study, carried out by MMR and Mingold (an
affiliate of HBED), put the estimates to be 2.23 million tonnes grading
3.6g/tonne (Northern Miner, March 12, 1990). This suggested a gold price of more
than $400 would be needed for the mine to be profitable. The gold prices were
extremely low at the time, therefore, the development of a mine was put on
Golden Band Resources optioned Mingold’s 44.83% interest with the right
to earn 100% of this interest, in 1992. Golden Band proceeded to complete a
$300,000, 18 hole, initial phase of drilling to test for additional shallow
reserves. The most encouraging holes resulted in 2 holes returning 12.7g Au over
1.1 metres in the first, and 5.1g Au over 6.2 metres in the second (Northern
Miner, August 21, 1992).
In 1994, Granduc Mining Corporation, which was an
amalgamation of Cazador Resources and Granduc Mining Inc. (Northern Miner,
November 22, 1993), acquired the option of Golden Band Resources to earn Mingold
Resources’ 44.8% interest in the Farley lake for $500,000 in Granduc
shares (Northern Miner, March 7, 1994). Granduc also signed a letter of intent
of purchase for MMR’s 55.2% controlling interest in the property, for a similar
amount. At this time, by investing $10 million in the project, Granduc could
earn up to 49% interest in Keystone from DCC equities, Black Hawk’s Parent
In 1996, Granduc and Black Hawk merged to form the new Black Hawk
Mining Inc. with 100% ownership of the Farley Lake deposit (Northern
Miner, February 2, 1996). Open pit mining at Farley Lake began in August
of 1996, as Black Hawk phased out the nearby BT pit mine (See: Mind No. 1043).
All mining operations in the area were smoothly transitioned to the Wendy Pit.
Reserves at the time were estimated at 1.4 million tonnes grading 3.9g/tonne Au
(Northern Miner, August 19th, 1996).
By 1997, the Keystone Gold Project had
shown an increase by 60% over the 1996 production, due to the increased grade.
The East Pit was also brought into production that year. In late 1998, the Wendy
pit was excavated to its ultimate depth, the de-watering system was
decommissioned, and the pit allowed to flood.
The Farley Lake mine
completed the mining operations of the East Pit in November 1999. The mine and
mill was put on hold and maintenance, in case any new deposits were discovered
in the area. In 2000, $1.2 million was spent towards reclamation and
rehabilitation programs, including treatment of effluent water in the holding
ponds, and the clean up and shut down of the Lynn Mill, this work continued
until late 2001 (Black Hawk Mining Inc., Annual Report 2000).
Year Ore Milled
(Tonnes) Average Grade (g/tonne) Gold
1998 473,652 4.14 59,647
1997 449,028 5.19
1996* 468,252 3.22 41,619
*1996 statistics are combined with BT
pit, which phased out in June (See: Mind No. 1043)
All statistics from Black
Hawk Mining Annual Reports, 1997-1998, 2000
2000: Annual Report.
1998: Annual Report
1996: Annual Report
Davies, J.F., Bannatyne, G.B., Barry, G.S. and
1962: Geology and Mineral Resources of Manitoba, p. 130,
Manitoba Mines Branch.
Fedikow, M.A.F., Baldwin, D.A. and Taylor,
1986a: Gold mineralization associated with the Agassiz metallotect and the
Johnson Shear Zone, Lynn Lake greenstone belt, Manitoba; in Gold in the Western
Shield Symposium (L.A. Clark, ed.); Canadian Institute of Mining and Metallurgy,
Special Volume 38, 1986, p. 361-377.
Fyon, J.A., Crocket, J.H., and Schwartz,
1983: The Carshaw and Malga iron-formation-hosted gold deposits of the
Timmins area; in The Geology of Gold in Ontario; Ontario Geological Survey,
Miscellaneous Paper 110, p. 98-110.
Manitoba Mines Branch
Assessment File (91041, 91836); Manitoba Mineral Resources Ltd., News release
(February 24, 1986).
1960: Geology of the Lynn Lake
District, Publication 57-1, p. 261, Manitoba Mines Branch.
1996: “ Prospects brighten for Black Hawk”, August 19.
1996: “ Black
Hawk and Granduc Mining sign merger deal”, February 2.
1994: “ Exploration
’94 – Busy Manitoba exploration scene”, March 7.
1993: “ Granduc reviews mill
expansion”, November 22.
1992: “ Cazador in option deal in northern
Manitoba”, August 21.
1990: “ Manitoba suffers slowdown in drilling
activity”, March 12.
Phillips, G.N., Groves, D.I., and Martin, J.E.
An epigenetic origin for Archean banded iron-formation-hosted gold deposits; in
Economic Geology, v. 79, p. 162-171.
1948: Geology of the
Farley Lake area; Manitoba Mines Branch, Preliminary Report 47-5, 22
Farley Lake area, (Geolo), Scale 1:63 360, Manitoba
Map 64C/16, Barrington Lake
Topo, Sc. 1:50 000, Surveys and
Mapping Branch, Ottawa. NAD 1927, 3rd Edition, 1984.
Lake, (Geolo), Scale 1:506 880 Geological Survey of Canada (1953).
Barrington Lake, (Aeromag), Scale 1:63 360, Manitoba Mines
Map No. 3
Barrington Lake, (Geol.), Scale 1:63 360 accompany
publication by Milligan (1960), Manitoba Mines Branch, Publication 57-1.
Bedrock Geology Compilation Map Series, 1:250 000, Granville
Manitoba Energy and Mines, Geological Services.
Preliminary Map 1980
Barrington Lake, (Geol.), Scale 1:50 000, Manitoba Mineral Resources