The Tom 3 showing is located roughly 3 kilometres northwest of Highland Surprise (082KSW037), 31 kilometres northwest of Kaslo, British Columbia.
A serpentinite belt, about 300 metres wide, cuts through the Kaslo Group adjacent to the Highland Surprise. The main lithologies of the area are assigned to the Permian Kaslo Group, consisting of andesite flows, pyroclastics and tuffaceous sediments. Volcanics are extensively chlorite altered and schistose. The reader is referred to the Highland Surprise for a more detailed description of the geology of the area. The serpentinite is largely altered to talc, chrysotile with grains of magnetite, chromite? and some carbonate. Pyroxene crystals have been altered to brucite and magnetite. Immediately south of the Tom 3 showing, quartzite of the Triassic Slocan Group crops out.
Cairnes (1934) reports "conspicuous amounts of talc" and mariposite developed on the property, where a large body of serpentine, located in the vicinity of the quartz veins, is largely altered to talc and brownish weathered (Ca-Mg-Fe) carbonate. The surrounding massive greenstones are altered to chlorite, serpentine, uralite, saussurite and albite. The alteration is believed to be related to intrusion of the Nelson batholith.
Chrysotile forms thin hairline-fracture fillings, 16 to 32 millimetres thick, in areas of intensely sheared serpentinite on the former Tom 1, 3 and 5 claims. The Tom 3 showing consists of chrysotile over 600 metres along the main shear zone. Hairline fractures are usually perpendicular to jointing and closely spaced with less than 2.54 centimetre separations. Diamond drilling at this showing in 1972 indicated asbestos was concentrated near a narrow pyroxenite dike. No concentrations greater than 5 per cent of 32 millimetre or longer chrysotile were found outside shear zone intersections with serpentinite. Average content was 2 per cent. Based on information obtained, this showing was considered of insufficient size, quality and grade to warrant further exploration (Assessment Report 3926).
