The area of the West Gossan is underlain by the contact of Upper Triassic volcanics of the Stuhini Group and volcanic rocks of the Tertiary to Quaternary Mount Edziza Complex.
The West Gossan area is located 800 metres west of the Spectrum, Central Zone (104B 036). The showing is located on a steep, rusty ridge that extends northwards from the edge of the basalt cap. Soil sampling in 2015 identified a strong gold-copper-silver-arsenic-lead-antimony-zinc geochemical anomaly in the area that measures approximately 630 by 230 metres. The IP chargeability geophysical high, that passes through the 300 Colour zone (to the east), projects into this general area.
Historical work, including prospecting and trenching, was completed in 1989 and 1990 by Cominco and Columbia Gold Mines. Three trenches (T-01, 02, and 03) were established to determine the source of high gold values in “talus fine” soil samples collected down-slope. All three trenches intersected gold mineralization, with the highest assay, (from T-03) yielding 3.8 gram per tonne gold over 1.0 metre. Trenches T-02 and T-03 yielded values of 0.42 gram per tonne gold over 13 metres and 0.61 gram per tonne gold over 34 metres, respectively (as reported in Assessment Report 36675). Trench mapping indicates that veins are oriented 155 to 175 degrees, dipping 50 to 80 degrees southwest. Cross fractures trend roughly east-west and dip 50 to 60 degrees north. The host rock is largely composed of weathered pyritic tuff. As of 2017, no drilling had been completed in this area.
Prospecting in 2015 identified several quartz-carbonate veins along the ridge, though most returned gold values less than 0.1 gram per tonne gold (Assessment Report 36675). On the northeast side of the ridge, a cluster of higher-grade samples were collected in the hangingwall of a northwest-trending normal fault. Six samples from this area yielded assay values ranging from 1.29 to 37.2 grams per tonne gold (Assessment Report 36675). All the higher-grade samples were obtained from quartz-carbonate veins that contain greater than 10 per cent sulphide material by volume with a gold-silver-arsenic-zinc-lead-antimony geochemical signature. Little is known of the widths and orientations of these samples. Sample 2641945 was a 0.25 metre chip sample that graded 37.2 grams per tonne gold, 16.3 grams per tonne silver 0.084 per cent zinc and 1 per cent arsenic; grab sample 2641942 graded 30 grams per tonne gold, 0.8 per cent copper, 544 grams per tonne silver, 15.1 per cent zinc, 0.78 per cent lead, 1 per cent arsenic and 0.33 per cent antimony (Assessment Report 36675).
The Southwest Gossan forms the southerly extension of the West Gossan and has a different soil geochemical signature dominated by gold with weak copper and arsenic. The small anomaly (110 by 110 metres) likely extends beneath the young basalt cap to the south. As of 2017, no significant prospecting or mapping had been completed in this area. The strength of the gold in soil anomaly (averaging 1202 parts per billion) may be an indication of buried high-grade gold veins).
