The Red Mountain talc deposit is near the British Columbia- Alberta border, in Kootenay National Park, and is situated on the north side of an easterly spur about 300 metres south of Talc Lake. Access to the deposit is 20 kilometres west of Banff, Alberta, where a secondary road leads off Highway 1 following Redearth Creek; from the mouth of Pharoah Creek a trail heads south into Redearth Pass and Talc Lake.
A series of talc bodies are exposed 300 to 1000 metres to the southeast of Talc Lake (Red Mountain and Gold Dollar, 082O 001 respectively), and also 1 kilometre northwest of Talc Lake (Saddle, 082O 003). They may represent erosional remnants of a once continuous and extensive zone. The bodies are in the hangingwall and close to and southwest of the northwest trending informally named Haiduk normal fault (Fieldwork 1992, page 365). The fault cuts through saddles along the spurs, two of which mark the contact between the Lower Cambrian Gog Group and Takakkaw tongue (slope facies of the Middle Cambrian Cathedral Formation). The talc bodies are just southeast and north of the northeast corner of an embayment in the Cathedral escarpment. There is a facies change at the Cathedral escarpment between the platformal Cathedral and Mount Whyte formations in the east, to the basinal Takakkaw tongue and Middle Cambrian Naiset Formation to the west. The Red Mountain and Gold Dollar occurrences are at the base of the Takakkaw tongue (or Naiset Formation), whereas the Saddle occurrences are at the base of the Cathedral Formation.
The talc deposit at Red Mountain is exposed along steep, mostly inaccessible bluffs above an extensive talus slope and below a cliff of the Takakkaw tongue and younger rocks. The cliff exposing the Cathedral escarpment is 550 metres to the north. In 1927, ten years after the occurrence was first staked, two short (10 and 15 metres) adits, 50 metres apart, were driven southerly into it by the National Talc Company. In 1930, Western Talc Holdings drilled five holes totalling 152 metres into the talc. In 1944, Wartime Metals Corporation developed a stope and raise at the end of the western adit.
The Red Mountain talc occurrence has a length of 260 metres and height of up to 30 metres. The gently southwest-dipping body appears stratabound and formed as replacement of dolomite in interbedded and intergradational thin-bedded dolomite, argillaceous dolomite and dolomitic carbonaceous argillites. In general, it is just above the lowermost occurrence of dolomite and is above the unconformity at the top of the Gog Group quartz arenites. The extreme eastern end of the talc body appears to be offset with a minimum dip-slip displacement of 10 metres along the Haiduk fault. The talc is also strongly deformed by steep to gently dipping shears and intersecting sets of non-pervasive subparallel fractures commonly spaced 0.5 to 15 centimetres apart.
The talc body weathers a dark rusty brownish orange resulting from oxidized pyrite shears and fractures. Most of the talc is dark grey to near-black on fresh surfaces, with 2 to 10 per cent dirty white and up to 50 per cent very light grey patches, lenses, spots and specks. Thin sections and x-ray diffraction analyses indicate the near-black colour results from a carbon compound and a few per cent chlorite (Fieldwork 1992, page 366). A distinct 18-metre interval of light grey talc with dirty white patches and lenses forms the hangingwall of the Haiduk fault.
Pyrite is very irregularly disseminated in the lighter coloured talc, commonly forming 0.5 to 1 per cent, to locally 3 per cent. Thin sections indicate that the black talc does not contain pyrite.
The talc is generally moderately to strongly fractured and sheared. Intersecting fractures and fracture cleavages commonly result in a brecciated texture.
