The Homestake deposit is located on Homestead Creek, approximately 21.5 kilometres south east of the community of Barriere.
The deposit is hosted by quartz-talc-sericite schists, sericite-quartz phyllite and sericite-chlorite-quartz phyllite derived from felsic to intermediate volcanic rocks (Unit EBA) of the Lower Cambrian and older(?) to Mississippian Eagle Bay Formation. The rocks are overlain by intermediate to felsic volcanic and volcaniclastic rocks (Unit EBF) which hosts the Rea Gold deposit (082M 191), 4 kilometres north. These units are overlain by metasedimentary rocks consisting of argillites, siltstones and grits, which are structurally overlain, to the east by mafic volcanic rocks (Unit EBG) (see Map 56 for unit descriptions).
The deposit lies on the southern limb of a northwest trending, tight, overturned syncline. An east dipping thrust fault is inferred to separate the felsic to intermediate metavolcanics and the more mafic metavolcanics to the east.
Several barite lenses with variable amounts of sulphides occur near the top of a bleached, rusty-yellowish weathered zone of pyritic sericite-quartz schist interpreted to be a highly altered, felsic tuff. The schistosity and compositional layering dip at shallow to moderate angles to the northeast. The main horizon consisting of massive to banded barite, metallic minerals and quartz-sericite are cut by veins and lenses of quartz. The metallic minerals include tetrahedrite, galena, sphalerite, pyrite, chalcopyrite, argentite, native silver and trace ruby silver and native gold. The bayle-basemetal deposit has an extremely large sericite mica envelope.
At least three zones of mineralization, referred to as the 300, 400 and 500 zones, have been identified above the 1750 Level adit and in the area of the 1750 raise. The 500 zone averages 6.8 to 10.5 metres in width and is comprised of a 0.3- to 2.4-metre wide lower barite zone and a 0.2- to 1.5-metre wide upper high-grade quartz schist zone separated by 4.5 to 6.0 metres of semi-barren schist to the west. The 400 zone, located approximately 21 to 23 metres above the 500 zone, varies from 3.0 to 9.0 metres in width from the west to east, averaging approximately 3.5 to 3.9 metres, and comprises massive barite. The zone appears to join with the 300 zone near the centre of the deposit and the two are separated by up to 12 metres of schists. The 300 zone is reported to vary from 3.0 to 9.0 metres in width with an average of approximately 6.0 to 7.0 metres. The ‘Barite Bluff’ outcrop is likely the surface exposure of the 300 zone. A series of narrow lenticular mineralized pods, known as the Hanging Wall zone, is located above the 300 zone. The mineralized zones are reported to have at least a 120-metre strike length and have been traced for at least 210 to 300 metres along dip. Mineralization is reported to be controlled by drag or cross folding associated with movement along the main 2250 fault. The 300 and 400 zones are cut-off to the southeast by the main 2250 fault.
Later work, in 2005, describes at least two subparallel massive sulphide-barite horizons. The horizons trend northwest and dip at shallow angles to the northeast. The lower horizon lies approximately 40 metres below the upper horizon. The horizons have been traced by diamond drilling for approximately 300 metres downdip and are reported to thicken downdip. The massive sulphide-barite lenses are developed near the structural footwall contact of a sequence of quartz porphyritic felsic tuffs with a cherty tuff or pyritic siltite horizon. The lenses strike 130 to 140 degrees, dip 30 degrees northeast and plunge 25 to 30 degrees east to northeast.
The Victory group is comprised of the Treasure (L.4567) and Signet (L.4568) Crown grants and the former Victory, Eldorado, Dixie and Bullion claims. Development work includes the Wright-Davidson adit and opencut on the Treasure claim, the Dixie adit and the Bullion adit, located approximately 570, 1650 and 2070 metres southeast of the Homestake deposit and at elevations of approximately 825, 645 and 625 metres, respectively. Mineralization comprises quartz-carbonate-sulphide (pyrite-galena-sphalerite) lenses and pods, up to 0.6 metre wide and 3.0 metres long, in quartz-sericite schists and quartzites.
The Silver King and Silver Queen claims are located approximately 1200 metres northwest of the Homestake deposit. Development work includes three adits, two inclined shafts and several opencuts. This work has been directed towards scattered quartz lenses, up to 60 metres long and varying from 0.05 to 1.50 metres in width, in a greenstone and quartz-talc schists and a shear zone, 4.5 metres wide and traced for 21 metres along strike, hosting quartz-sulphide (pyrite-chalcopyrite-sphalerite-galena) pods/lenses, averaging 0.1 by 0.3 metre in size. The shear zone strikes north 20 degrees west and dips 50 degrees northeast. A sample from a 0.1-metre wide mineralized pod in the shear zone is reported to have assayed 48.6 grams per tonne gold, 1129 grams per tonne silver and 0.9 per cent lead (Annual Report 1936).
Bands, up to 600 metres wide, of sericite and quartz-sericite extend for up to 7 kilometres from Squaam Bay northwest. The sericite schist is fine-grained, fissile and weathers yellow due to ferric sulphate coating. Nodules of augen-like quartz give the rock a mottled appearance (Z.D. Hora, personal communication, 1990). X-ray diffraction analyses in 1987, by the Ministry of Energy, Mines and Petroleum Resources found talc to be a component in a number of samples of quartz-sericite schist. This deposit is a major potential sericite-mica resource in British Columbia. The large sericite envelope of the deposit represents a metamorphosed alteration zone that is of potential interest as a source of mica and may contain substantial reserves of fine-grained muscovite within the sericite schist.
In 1974, four chip samples (H-01 to -04) from underground workings on the 500 vein/zone yielded an average of 2.81 per cent zinc, 1.56 per cent lead, 0.26 per cent copper, 74.2 per cent barite, 260.9 grams per tonne silver and 1.1 grams per tonne gold over 10.8 metres (Property File – Goring A.W. [1974-03-12]: Letters regarding the Kamad and Homestake Property).
In 1980, a drillhole (U-14) on the 500 zone yielded 60.9 grams per tonne silver, 0.09 per cent copper, 0.34 per cent lead and 0.70 per cent zinc over 25.17 metres (16.5 metres true width; Property File – Silversides, D.A. [1980-06-01]: Homestake Property Evaluation). Also at this time, drilling on the 400 zone is reported to have yielded 205.2 and 239.4 grams per tonne silver over 4.2 and 3.6 metres in holes U-15 and U-17, respectively (Property File – Hicks, H.B. [1981-07-30]: Re: Review of Current Situation).
In late 1981 and early 1982, underground drilling on the 500 zone yielded intercepts including 0.33 and 0.35 gram per tonne gold, 150.0 and 120.6 grams per tonne silver, 0.18 and 0.18 per cent copper, 0.90 and 1.01 per cent lead, 1.83 and 1.94 per cent zinc with 52.2 and 35.1 per cent barite over 23.04 and 11.40 metres in holes 82-2 and 82-5, respectively (Property File – Jenks, J. [1982-04-01]: Diamond Drill Record - Hole No. 82-2 - Kamad).
In 1983, three underground samples (0602 through 0604) from the 500-zone averaged 0.21 gram per tonne gold, 182.4 grams per tonne silver, 0.23 per cent copper, 0.16 per cent lead, 1.68 per cent zinc and 14.9 per cent barium (Property File - CDN Resource Laboratories Ltd. [1983-12-22]: Assay Report - File No. 83-214 - Falconbridge Copper Corp. - Kamad). Two drill holes (No.14 and No.16) on the 300 zone yielded 3.83 and 8.14 grams per tonne gold, 1344 and 782.2 grams per tonne silver, 2.99 and 9.99 per cent lead, 5.17 and 21.43 per cent zinc, 1.07 and 2.24 per cent copper with 39.01 and 18.16 per cent barite over 4.05 and 3.00 metres, respectively (Property File - O'Hara, T.A. [1985-05-01]: Feasibility Study - Homestake Mine).
Also at this time, a sample from the Barite Bluffs zone assayed 0.18 per cent copper, 1.49 per cent zinc, 1.77 per cent lead, 172.4 grams per tonne silver and 0.51 gram per tonne gold (Property File – Davidson, A.J. [1983-08-08]: Proposed Reconnaissance at Adams, Barriere).
Probable reserves are 249,906 tonnes grading 226.6 grams per tonne silver, 36.7 per cent barite, 0.28 per cent copper, 1.24 per cent lead, 2.19 per cent zinc and 0.58 grams per tonne gold (Statement of Material Facts 06/06/86, Kamad Silver Company Ltd.). Caving occurs in unsupported ground. Test milling in 1981 was completed for flow sheet design.
In 1987, drillhole KAM-26, located at an elevation of approximately 790 metres and 700 metres to the southeast of the Homestake workings, yielded intercepts of 0.13 and 0.10 gram per tonne gold, 7.1 and 30.8 grams per tonne silver, 1.50 and 1.9 per cent lead with 9.30 and 2.50 per cent zinc over 0.4 and 0.3 metre (84.4 to 84.8 and 130.0 to 130.3 metres downhole), respectively, from bands of semi-massive to massive sulphides (pyrite-spalerite-galena-chalcopyrite-tetrahedrite) with quartz and dolomite in a felsic volcanic (Assessment Report 16701). Another drillhole (KAM-27), located at an elevation of approximately 690 metres and 400 metres southeast of the previous drillhole, yielded 26.5 grams per tonne silver, 0.17 per cent copper, 4.40 per cent lead and 1.13 per cent zinc over 0.3 metre (191.2 to 191.5 metres downhole; Assessment Report 16701).
In 1988, a possible additional reserve of 27 884 tonnes grading 824.2 grams per tonne silver, 4.61 per cent lead, 7.66 per cent zinc and 1.07 per cent copper was reported for a narrow high-grade zone located along a 75-metre strike-length of the hangingwall of the 300 zone (Property File – Friesen, R.G. [1988-11-30]: Report on Kamad Silver Co. Homestake Property Excluded Area).
In 2005, drilling on the area of the historic Homestake workings yielded intercepts including 459, 285, 508 and 287 grams per tonne silver; 2.70, 1.05, 2.44 and 0.34 grams per tonne gold; 1.27, 0.41, 0.31 and 0.26 per cent copper and 5.95, 1.11, 0.98 and 1.17 per cent lead with 9.17, 2.23, 1.15 and 1.93 per cent zinc over 7.2, 9.1, 3.5 and 7.6 metres (61.0 to 68.2, 80.1 to 89.2, 111.0 to 114.5 and 156.0 to 163.6 metres downhole) in holes MX5-03, -04, -05 and -08(?), respectively (Property File - Amarc Resources Ltd. [2005-03-22]: Amarc drilling encounters strong silver values at massive sulphide target in central British Columbia).
Also at this time, a drillhole (MX5-16), located at an elevation of approximately 960 metres upslope and north of the Homestake mine workings, yielded intercepts of up to 0.42 gram per tonne gold, 87.5 grams per tonne silver, 0.135 per cent copper, 0.723 per cent lead and 1.380 per cent zinc over 0.9 metre (321.4 to 322.3 metres downhole; Assessment Report 28277).
Earliest history of work within the claim area occurred during 1893-1894 when the exploration interest in the outcropping barite and massive sulphide lenses was initiated.
These mineralized zones would form the nucleus of the Homestake Mine. This led to 2,500 tonnes of production during 1926 and 1927 followed by the erection of a 27 tonne per day mill in 1935. Between 1935 and 1936, 2,700 tonnes of massive sulphides and barite ore were processed.
The property was essentially dormant until 1970 when Kamad Silver Ltd. acquired both the crown grants and surrounding mineral claims. Canadian Reserve Oil and Gas acquired the claims in the early 1980’s and completed the development of an 800 metre drift on the 1750 level which was connected to the 2250 level workings by a single raise collared from near the northeast terminus of the 1750 drift. Detailed underground sampling and mapping was carried out and 2,072 metres of underground drilling was completed, along with 2,993 metres of surface drilling. The mine was re-opened during the winter of 1983/1984.
Esso Minerals conducted a significant exploration program on these claims from 1986 to 1989. Homestake Canada Ltd. assumed interest in Esso Minerals mineral properties in 1989. In the 1990's, the Kamad and Twin claims were allowed to lapse.
In 1999, these claims were re-staked by Eagle Plains Resources Ltd. The claims were optioned to Amarc Resources Ltd. in December of 2004. In 2005, Amarc completed geological mapping programs, lithogeochemical studies and 3,639 metres of NQ diamond drilling in 16 boreholes.