Ross No. 15 occurrence is located on the east side of Climax Creek at an elevation of approximately 1020 metres.

The area is underlain by granodioritic intrusive rocks of the Middle Jurassic Nelson Batholith and granitic intrusives of the Paleocene to Eocene Sheppard, Tuzo and Shingle Creek intrusions. To the west, Carboniferous to Permian undivided metamorphic rocks are exposed.

Locally, a 95-centimetre wide quartz vein, referred to as the ‘Tough’ vein, hosts galena and pyrite mineralization.

In 1976, a grab sample of vein material assayed 131.7 grams per tonne silver and 0.6 gram per tonne gold, whereas a sample of quartz float from a trench located 30 metres to the east yielded 32.8 grams per tonne silver and 2.07 per cent lead (Property File - D.W. Tully [1976-10-18]: Geological Report on the Republic Property).

The area has been explored since the 1890s, in conjunction with the nearby Republic No. 2 (MINFILE 082FNW168) past-producing mine. Past workings include at least one adit and several pits and/or trenches.

During 1972 through 1979, Tandem Resources Ltd. examined the area. Exploration programs included geochemical sampling, geological mapping, trenching and an induced polarization survey.

In 2011, Moose Mountain Technical Services, on the behalf of Rainbow Resources Inc., completed a program of prospecting and geochemical (rock and soil) sampling on the area as the Big Strike property