The Fourth (L.301) occurrence is located at an elevation of approximately 1630 metres on the north side of Coffee Creek, approximately 5 kilometres southwest of Ainsworth.

Regionally, the area is underlain by hornblende schists, limestone and banded quartzite of the Upper Mississippian to Permian Milford Formation and basaltic volcanic rocks of the Carboniferous to Permian Kaslo Group. Granodioritic intrusive rocks of the Middle Jurassic Nelson Batholith are exposed to the west.

The occurrence is situated near the contact of Mississippian to Permian Milford Formation strata, consisting of argillite, limestone and quartzite, and porphyritic granite, granodiorite and granite gneiss of the Middle Jurassic Nelson Batholith. A vein, 0.9 to 1.3 metres wide, hosting galena, pyrite and sphalerite strikes southeast in a brecciated and faulted argillaceous limestone.

Assays indicated 686 to 2606 grams per tonne silver and 10 to 38 per cent lead.

In 1979, samples (B, E, and G) of fault zone material yielded an average of 3.9 per cent lead, 9.8 per cent zinc and 219 grams per tonne silver, whereas a sample (A) of black argillaceous limestone assayed 14.9 per cent lead, 3.52 per cent zinc and 291 grams per tonne silver (Assessment Report 8192).

Work History

In 1895, a 152-metre long tunnel was driven, and further underground development took place in the 1930s. The adit portal is reported to be located at an elevation of 1628 metres, and an upper shaft or winze is located at approximately 1673 metres elevation.

In 1968, approximately 5.5 tonnes of mud and high-grade ore was stacked but not shipped. In 1979, Tri Country Holdings Ltd. conducted a program of geological mapping, rock sampling, stripping and trenching.

During 2007 through 2011, Goldcliff Resource Corp. completed programs of prospecting, geological mapping, geochemical (rock, silt and soil) sampling and an airborne geophysical survey on the regionally extensive Ainsworth Silver property. In 2015, Goldcliff Resource Corp. conducted a program of prospecting, geological mapping, geochemical (rock, silt and soil) sampling and a 4.1 line-kilometre ground electromagnetic survey on the area as part of the Ainsworth Silver property.