The Butler prospect is located at the headwaters of Farnham Creek, on the west flank of Black Diamond Mountain in the Golden Mining Division. The property consists of two Reverted Crown grants (Lots 9989 and 9990).
Regionally, the area is underlain by Proterozoic clastic sedimentary rocks of the Purcell and Windermere supergroups and by lower Paleozoic strata of the Beaverfoot and Mount Forster formations (Geoscience Map 1995-1).
The Purcell Supergroup strata include the Aldridge, Creston, Kitchener, Dutch Creek and Mount Nelson formations. The Windermere Supergroup unconformably overlies the Purcell Supergroup rocks and includes the Toby Formation and Horsethief Creek Group (Paper 1990-1).
In the vicinity of the occurrence, rocks of the Kitchener and Dutch Creek formations have been further subdivided and assigned to the Van Creek and Gateway formations. The Van Creek Formation correlates with the Lower Kitchener Formation while the Gateway Formation is equivalent to the lower portion of the Dutch Creek Formation. The Mount Nelson Formation has been subdivided into seven discrete members, a lower quartzite, a lower dolomite, a middle dolomite, a purple dolomite, an upper middle dolomite, an upper quartzite, and an upper dolomite (Open File 1990-26).
Rocks of the Horsethief Creek Group, Beaverfoot and Mount Forster formations are folded and overthrusted by rocks of the upper portion of the Dutch Creek Formation and the lower members of the Mount Nelson Formation.
The sedimentary rocks have undergone regional metamorphism to at least greenschist facies.
The prospect consists of a vertical fissure vein within silicified dolomitic limestone of the Mount Nelson Formation. Mineralization includes galena, pyrite, chalcopyrite, freibergite, azurite and malachite in a gangue of quartz and barite.
The vein has been explored with two adits and a 150 metre long crosscut. A 50 centimetre chip sample across the mineralized vein assayed 250 grams per tonne silver, 3.0 per cent copper, 1.26 per cent zinc and 0.5 per cent lead (Assessment Report 21066).
