The Bristol occurrence straddles Tommy Creek at an elevation of 1170 metres, approximately 3.5 kilometres south of the creek mouth on Carpenter Lake.
The area in which the prospect occurs is underlain by cherty quartzites, argillites, metabasalt and crystalline limestone lenses of the Mississippian to Jurassic Bridge River Complex (Group). The stratigraphy generally strikes north- northeast and dips steeply west, although some large- scale folding along north west–trending axes is also evident. The sequence is intruded by two plutons, probably related to the Cretaceous to Tertiary Bendor pluton, each approximately 1 kilometre in diameter and consisting of granodiorite and porphyritic granite. Minor amounts of felsic, mafic and ultramafic dikes also occur.
Gold mineralization occurring in the vicinity of the Bristol workings is hosted by five shear zones (East, Hangingwall, Main, Footwall, Tommy Creek) in which the rocks are variably altered to an assemblage of quartz, carbonate, clay, pyrite, pyrrhotite and limonite. The principal rock type within the shear zones is a cherty quartzite. The Main shear zone is believed to contain fairly uniform but low gold content but with some lenses or pipes of high-grade gold and/or gold-tungsten. The shear zones trend from 32 to 37 degrees and vary from approximately 0.4 to 6 metres in width. They dip steeply to the east and are relatively continuous. The shear fillings usually consist of fractured quartzite banded by gouge seems; coatings and veinlets of calcite are common and stringers of quartz less common.
The sulphides include major amounts of pyrite, arsenopyrite and marcasite together with very minor amounts of sphalerite, galena and chalcopyrite. Tungsten occurs in the form of scheelite, which generally can not easily be detected in hand specimens. Gold occurs mainly in arsenopyrite and pyrite with lesser amounts within quartz; the highest grade ore was reported to contain small quartz stringers which contained pyrite, arsenopyrite and large grains of scheelite. Ore grades from the workings vary considerably.
Historical samples from drilling and underground workings are reported to have assayed up to 30.8 grams per tonne gold and 6.5 per cent tungsten trioxide (Assessment Report 15304). A 23 kilogram sample taken from a winze is reported to have assayed 0.16 per cent tungsten trioxide (WO3), 48 grams per tonne gold and 20.6 grams per tonne silver (Bulletin 10, page 106).
In 1988, diamond drilling yielded up to 0.89 gram per tonne gold over a true width of 0.25 metre from the Main shear zone, 1.59 grams per tonne gold over a true width of 0.75 metre from the Hangingwall shear zone, 3.97 grams per tonne gold over a true width of 0.84 metre from the Footwall shear zone and 7.5 grams per tonne gold over a true width of 0.5 metre in the Tommy Creek shear zone (Assessment Report 18618).
During 1939 through 1946, Bristol Mines Ltd. completed three adits and short winze, totalling approximately 333 metres of drifting. In 1947, a 2,743- metre underground diamond drill program was completed. In 1973 and 1978, the area was examined by Camero Resources. In 1980 and 1981, Columbia Capitol Co. Ltd. completed a program of geological mapping, soil sampling and four diamond drill holes. In 1986, Fairchild Resources completed a program of rock and soil sampling, trenching, geological mapping and ground geophysical surveys on the area. In 1987, Equinox Resources soil sampled the area as the Ray claims. During 1988 through 1992, Westmin Resources completed programs of soil and rock sampling, geological mapping and four diamond drill holes, totalling 480.2 metres, on the Bristol claims.
