The M.T. Fraction consists of one Reverted Crown grant (Lot 10110) which is located on the southeast flank of Mount Catherine, on the north side of Delphine Creek in the Golden Mining Division, at an elevation of 1677 metres.
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 M.T. Fraction is hosted within dolomite of the Mount Nelson Formation. The occurrence consists of a quartz-carbonate vein 20 to 30 centimetres wide which has been explored with a small adit. Limited production at the turn of the century yielded 254,641 grams of silver, 1655 kilograms of copper and 39 kilograms of lead. Ore minerals include galena, tetrahedrite and chalcopyrite with minor sphalerite. The vein is within a dilatant zone along a normal fault that strikes southeast and dips 80 degrees west.