The Big Spring (Winchester Road) occurrence is located on north facing slopes, south of McDonald Creek approximately 12 kilometres east of Upper Arrow Lake.

Regionally, the area is underlain by a sequence of Devonian-Mississippian pelitic quartzites and pelites belonging to the Silver Creek Formation and Milford Group; Upper Triassic, Lower Jurassic carbonaceous meta-mudstone with minor calcareous quartzite and limestone belonging to the Slocan Group, and rare volcanic breccia of the Rossland Group. These have been intruded by Jurassic diorite porphyry dikes and sills, Cretaceous granite stocks and dikes and Tertiary lamprophyre dikes. The area covers a southeast- plunging, gentle anticline roughly parallel to McDonald Creek and north trending faults, possibly Tertiary, dissect the area.

Locally, an intrusive hosts quartz veining with sulphides. The sulphide mineralogy was not described.

In 1988, channel samples from a road cut assayed up to 0.58 gram per tonne gold and 14.5 grams per tonne silver (Assessment Report 18446).

In 1982 and 1983, Nuspar Resources completed programs of silt and soil sampling, geological mapping and ground and airborne geophysical surveys on the area. In 1988, Meadow Mountain Resources completed a program of geochemical sampling, geological mapping and ground geophysical surveys on the area.

In 2008, an airborne electromagnetic and magnetometer geophysical survey was conducted for Kootenay Gold Inc., and Theia Resources Ltd. on the property containing the occurrence. Results correlated with orientation and placement of the Ruby Range, Meadow Mountain, and affiliated quartz diorites, and the local sill-mudstone complex (Thompson, R. (2008-12-01): Technical Report on Geology, Exploration Programs and Results from the Rosetta Stone Property with Recommendations for Further Exploration).