The dominant host rocks at the Ridge and AW zones are andesitic(?) volcanic breccias. Conspicuous augite phenocrysts in these rocks are diagnostic of a stratigraphic position within the Stuhini Group.
The AW zone is situated at the top of the West Nunatak and is underlain by sedimentary rocks and volcanic rocks. The zone is exposed within a series of trenches and comprises quartz veining with up to 20 per cent chalcopyrite and galena within silicified and sericitized wallrock. Surface samples collected from this zone by Tantalus Resources Ltd. assayed up to 178.29 grams per tonne gold and 936 grams per tonne silver (5.2 opt Au and 27.3 opt Ag) (Assessment Report 23686). In 1991, five diamond drill holes totalling 141 metres were collared to test the extent of mineralization within the AW zone. Of the five drill holes TC91-1 was the only hole to intersect mineralization and assayed 5.45 grams per tonne gold and 237.95 grams per tonne silver over 4.7 metres (Assessment Report 21318, 23686). Mineralization is characterized by up to 20 per cent galena, 15 per cent chalcopyrite and 10 per cent pyrite within sericite+calcite altered volcanic rocks.
Chalcopyrite and pyrite are reported to occur in outcrop on the eastern edge of the Johnstone Icefield in the same vicinity as the Ridge and AW showings; this MINFILE occurrence was previously named Johnstone. (Open File 1988-4).