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File Created: 24-Jul-85 by BC Geological Survey (BCGS)
Last Edit:  28-Mar-09 by Gloria Robinson(GLR)

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NMI 093L1 Ag1
Name EQUITY SILVER, SAM GOOSLY, S.G., MAIN, WATERLINE, SOUTHERN TAIL, EQUITY, NORTHERN Mining Division Omineca
BCGS Map 093L019
Status Past Producer NTS Map 093L01W
Latitude 54º 11' 22" N UTM 09 (NAD 83)
Longitude 126º 15' 48" W Northing 6008059
Easting 678550
Commodities Silver, Copper, Gold, Antimony, Arsenic Deposit Types L01 : Subvolcanic Cu-Ag-Au (As-Sb)
Tectonic Belt Intermontane Terrane Stikine
Capsule Geology

Silver, copper and gold are produced from the Equity Silver deposit. In addition antimony and arsenic were leached from the concentrate and recovered as byproducts; however, due to metallurgical difficulties this process was discontinued.

The mineral deposits are located within an erosional window of uplifted Cretaceous age sedimentary, pyroclastic and volcanic rocks near the midpoint of the Buck Creek Basin. Strata within the inlier strike 015 degrees with 45 degree west dips and are in part correlative with the Lower-Upper Skeena(?) Group. Three major stratigraphic units have been recognized. A lower clastic division is composed of basal conglomerate, chert pebble conglomerate and argillite. A middle pyroclastic division consists of a heterogeneous sequence of tuff, breccia and reworked pyroclastic debris. This division hosts the main mineral deposits. An upper sedimentary-volcanic division consists of tuff, sandstone and conglomerate. The inlier is flanked by flat-lying to shallow dipping Eocene andesitic to basaltic flows and flow breccias of the Francois Lake Group (Goosly Lake and Buck Creek formations).

Intruding the inlier is a small granitic intrusive (57.2 Ma) on the west side, and Eocene Goosly Intrusions gabbro-monzonite (48 Ma) on the east side.

The chief sulphides at the Equity Silver mine are pyrite, chalcopyrite, pyrrhotite and tetrahedrite with minor amounts of galena, sphalerite, argentite, minor pyrargyrite and other silver sulphosalts. These are accompanied by advanced argillic alteration clay minerals, chlorite, specularite and locally sericite, pyrophyllite, andalusite, tourmaline and minor amounts of scorzalite, corundum and dumortierite. The three known zones of significant mineralization are referred to as the Main zone, the Southern Tail zone and the more recently discovered Waterline zone. The ore mineralization is generally restricted to tabular fracture zones roughly paralleling stratigraphy and occurs predominantly as veins and disseminations with massive, coarse-grained sulphide replacement bodies present as local patches in the Main zone. Main zone ores are fine-grained and generally occur as disseminations with a lesser abundance of veins. Southern Tail ores are coarse-grained and occur predominantly as veins with only local disseminated sulphides. The Main zone has a thickness of 60 to 120 metres while the Southern Tail zone is approximately 30 metres thick. An advanced argillic alteration suite includes andalusite, corundum, pyrite, quartz, tourmaline and scorzalite. Other zones of mineralization include a zone of copper-molybdenum mineralization in a quartz stockwork in and adjacent to the quartz monzonite stock and a large zone of tourmaline-pyrite breccia located to the west and northwest of the Main zone.

Alteration assemblages in the Goosly sequence are characterized by minerals rich in alumina, boron and phosphorous, and show a systematic spatial relationship to areas of mineral deposits. Aluminous alteration is characterized by a suite of aluminous minerals including andalusite, corundum, pyrophyllite and scorzalite. Boron-bearing minerals consisting of tourmaline and dumortierite occur within the ore zones in the hanging wall section of the Goosly sequence. Phosphorous-bearing minerals including scorzalite, apatite, augelite and svanbergite occur in the hanging wall zone, immediately above and intimately associated with sulphide minerals in the Main and Waterline zones. Argillic alteration is characterized by weak to pervasive sericite-quartz replacement. It appears to envelope zones of intense fracturing, with or without chalcopyrite/tetrahedrite mineralization.

The copper-silver-gold mineralization is epigenetic in origin. Intrusive activity resulted in the introduction of hydrothermal metal-rich solutions into the pyroclastic division of the Goosly sequence. Sulphides introduced into the permeable tuffs of the Main and Waterline zones formed stringers and disseminations which grade randomly into zones of massive sulphide. In the Southern Tail zone, sulphides formed as veins, fracture-fillings and breccia zones in brittle, less permeable tuff. Emplacement of post-mineral dikes into the sulphide-rich pyroclastic rocks has resulted in remobilization and concentration of sulphides adjacent to the intrusive contacts. Remobilization, concentration and contact metamorphism of sulphides occurs in the Main and Waterline zones at the contact with the postmineral gabbro-monzonite complex.

The Equity Silver mine was British Columbia's largest producing silver mine.

The Southern Tail deposit has been mined out to the economic limit of an open pit. With its operation winding down, Equity Silver Mines does not expect to continue as an operating mine after current reserves are depleted. Formerly an open pit, Equity is mined from underground at a scaled-down rate of 1180 tonnes-per-day. Proven and probable ore reserves at the end of 1992 were about 286,643 tonnes grading 147.7 grams per tonne silver, 4.2 grams per tonne gold and 0.46 per cent copper, based on a 300 grams per tonne silver-equivalent grade. Equity has also identified a small open-pit resource at the bottom of the Waterline pit which, when combined with underground reserves, should provide mill feed through the first two months of 1994 (Northern Miner - May 10, 1993).

Equity Silver Mines Ltd. ceased milling in January 1994, after thirteen years of open pit and underground production. Production totalled 2,219,480 kilograms of silver, 15,802 kilograms of gold and 84,086 kilograms of copper, from over 33.8 Million tonnes mined at an average grade of 0.4 per cent copper, 64.9 grams per tonne silver and 0.46 gram per tonne gold.

Bibliography
EMPR AR 1968-137
EMPR BC METAL MM00009
EMPR BULL *64, p. 150
EMPR ENG INSP Annual Report 1989, 1990
EMPR EXPL 1975-138; 1977-189; 1978-215; 1979-224; 1984-321; 1985-310; 1986-349-350; 1987-C300,C301; 1988-C167
EMPR FIELDWORK 1974, p. 79; 1976, p. 55; *1978, pp. 132-137; *1979, pp. 123-125; 1980, pp. 25-31; 1981-229-233; *1984, pp. 174-187; 1991, p. 232; 1992, pp. 475-481; *1997, pp. 23-1-23-10
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EMPR P *1990-2
EMPR PF (*Equity Silver Mines Annual Report 1985; Equity Mining Capital Annual Report 1975; Sam Goosly Project Information Summary, Oct 1975; Preliminary Environmental Impact Study on the Proposed Sam Goosly Project, Feb 1976; Beak Consultants Ltd., An Environmental Baseline Survey for the Sam Goosly Project, March 1974; Beak Consultants Ltd., Sam Goosly Project Stage II Detailed Assessment, Sept 1976; Property description excerpt; Geological notes and field notes; Equity Silver Mines Ltd. site plan, 1982; Wetherell, D.G and Sinclair, A.J. (1979): Preliminary Report on Stratigraphy and Genesis of the Sam Goosly Copper-Silver-Antimony Deposit; Report on Equity Silver Mines Limited, Canadian Research Report, Jan.13, 1982; Titanium in Tailings of Porphyry Deposits in British Columbia, by Y.T.J. Kwong; Monthly report, June 1981, Smithers Office; Project Summary: Acid Drainage from the Mine Walls: The Main Zone pit at Equity Silver Mines, BCAMD 1.15, September 1990, Natural Resources Canada; Executive Summary, Geochemical Assessment of the Equity Silver Tailings Pond, MEND Report 2.11.5c, August 1996, Natural Resources Canada)
EMR Canadian Mineral Industry Monthly Report, January 1990
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GSC BULL 270, 73 pp.
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CIM BULL Vol. 83, No. 934, pp. 69-76 (Church, B.N. and Pettipas, A.R. (1990): Interpretation of the Second Derivative of Aeromagnetic Maps at the Silver Queen and Equity Silver Mines, Houston, B.C.)
CIM Reporter Oct.30, 1981; Mar. 1982; Sept. 1983; Dec. 1985 p. 84-93
CMJ April 1992
GCNL #13,#20, 1976; #11, 1977; #232, 1978; #46,#146,#152,#169,#229, 1979; #36,#40,#56,#145,#152,#208, 1980; #34,#38,#80,#146,#206, #212, 1981; #28,#82,#83,#85,#148,#209,#210, 1982; #23,#82,#143, #144, 1983; #12,#31,#39,#81,#146,#240, 1984; #28,#81,#115,#120, #208, 1985; #131,#143,#213, 1986; #38,#55,#222,*#154, 1988; #87(May 6), 1993
MIN REV Nov/Dec, 1981; Mar/Apr, 1982; July/Aug 1982
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CIM BULL Vol. 69, pp. 88-95 (Church, B.N., Barakso, J.J. and Bowman, A.F. (1979): Endogenous Distribution of Minor Elements in the Goosly-Owen Lake Area of Central British Columbia)
CIM BULL Vol.65, pp. 53-64 (Ney, C., Anderson, J.M. and Panteleyev, A. (1972): Discovery, Geologic Setting and Style of Mineralization, Sam Goosly Deposit)
ECON GEOL Vol.79, pp. 969-990 (*Wojdak, P.J. and Sinclair, A.J. (1984): Equity Silver Ag-Cu-Au Deposit; Alteration and Fluid Inclusion Studies)
ECON GEOL Vol. 79, pp. 947-968 (*Cyr, J.B., Pease, R.B. and Schroeter, T.G. (1984): Geology and Mineralization at Equity Silver Mine)
W MINER, Vol.57, No.4, pp. 50-54 (Kowalchuk, J.M., Church, B.N., Bradshaw, P.M.D. and Barakso, J.J. (1984): Lithogeochemistry at the Equity Silver Mine; August 1981)
Church, B.N. (1993): The North Zone, Equity Silver Mine, EMPR Unpublished report.
Metals Week Feb 27, 1984
Placer Dome File
Wetherell, D.G. (1979): Geology and Ore Genesis of the Sam Goosly Copper-Silver-Antimony Deposit, British Columbia, M.Sc. Thesis, University of British Columbia
Wojdak, P.J. (1974): Alteration of the Sam Goosly Copper-Silver Deposit, British Columbia, M.Sc. Thesis, University of British Columbia

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