Snowflake Mine, Mount Cotterell, Revelstoke Mining Division, British Columbia, Canadai

Regional Level Types
Snowflake Mine	Mine
Mount Cotterell	- not defined -
Revelstoke Mining Division	Division
British Columbia	Province
Canada	Country

The Snowflake mine is located near the junction of Woolsey and Clabon creeks, about 3 kilometres north-west of Mount Cotterell, and about 31 kilometres north-east of Revelstoke, British Columbia. The Snowflake workings are continuous with those of the Woolsey or Regal Silver mine (MINFILE 082N 014). Because the Snowflake is better known in the literature, it has been chosen as the principal reference.
There are descriptions of both deposits, and the area, on the British Columbia “Minfile” site, current to 2019. Brief excerpts for Snowflake are quoted below – those for Woolsey do not differ significantly:
“The area is underlain by black, fissile graphitic slates with local minor variations in carbonate and silica content, and thin-bedded, dark-grey argillaceous limestone and limy argillite of the Cambrian to Devonian Index Formation (Lardeau Group). These rocks strike northwest and dip from 35 to 60 degrees northeast. A well-developed, slaty cleavage parallel to bedding is universally present. A pronounced system of jointing trends northeast and dips steeply southeast. All of the sediments are cut by numerous, small, barren quartz stringers.
Locally, a system of northwest–striking, mineralized, subparallel quartz veins occurs in slates over an area of 3.5 by 1 kilometres and has been subjected to exploration and underground development on the Snowflake and Woolsey (MINFILE 082N 004) occurrences. The veins vary in width from a few centimetres to 6 metres, but widths between 0.6 and 2.4 metres are most common.
The quartz veins are generally coarsely crystalline, crushed and fractured and normally contain wallrock fragments and minor calcite. The veins strike northwest and dip 60 to 35 degrees northeast, with faulting both across and along the veins. They are variably mineralized with argentiferous galena, sphalerite, pyrite and minor chalcopyrite. Minor amounts of tetrahedrite, pyrargyrite, native silver and pyrrhotite were identified by microscope examination. The oreshoots are extremely irregular, pinching and swelling in the vein, and their continuity cannot be assumed to extend for any distance beyond an exposure. The oreshoots generally occur on the footwall sides of the veins but are occasionally found in the hangingwall.
Stannite has been identified from a sample of the mineralized vein in the Snowflake workings and is associated with pyrite-chalcopyrite-sphalerite; it occurs very sparingly in the Woolsey workings. Scheelite has also been identified in the Snowflake workings but occurs widely in the Woolsey workings as small masses widely scattered in the veins, and as concentrations in pyritic lenses. Fluorite has also been reported to occur with the scheelite.”
Comments by Giles Peatfield on some of the minerals reported from the locality:
There are numerous minerals already listed on Mindat for this occurrence. Many of these have references simply copied from the “Minfile” page. I have chosen to expand these references, by going back to the original sources. Several of the minerals listed here are not presently on the Mindat page, and I have provided detailed references for these.
Actinolite: Reported in drill core by Goad (1980) and by Goad & Hodgson (1980).
Andalusite: Reported in drill core by Goad (1980) and by Goad & Hodgson (1980).
Arsenopyrite?: Reported by Goad (1980) as a possible trace in drill core. The significance of the existing reference, Anthony, et al. (1980), is not immediately obvious.
Biotite: “Brown biotite” reported from drill core by Goad (1980).
Canfieldite: Reported only by Harris & Owens (1972), who noted it is “Te-bearing”.
Cassiterite: Reported only by Harris & Owens (1972).
Cerussite: Reported only by Harris & Owens (1972).
Covellite: Reported only by Harris & Owens (1972).
Diopside: Reported from drill core by Goad (1980).
Fluorite?: Reported on the “Minfile” page, but Goad & Hodgson (1980), who were hoping to see it as their target was a molybdenum deposit, specifically noted that it was not present in drill core; nor did they report molybdenite. Neither Stevenson (1943), who examined the tungsten mineralization in detail, nor Harris & Owens (1972) in their detailed mineralogical examination mentioned fluorite. I would suggest that it is not likely for the deposit.
“Garnet”: Reported from drill core by Goad (1980), who gave no details.
Graphite: Specifically reported by Stevenson (1943) and by Goad (1980); several other workers mention “graphitic” sedimentary rocks.
Kësterite: Harris & Owens (1972) described this in detail, as an intergrowth with stannite (q.v.). Interestingly, Campbell (1952) noted that “A fine, sub-graphic intergrowth . . . was noted under crossed nicols. The intergrowth was more pronounced in places where stannite displayed strong anisotropism. Etch reactions gave similar tests for both stannite and the ex-solved mineral. Physical properties were also alike, except for the colour difference under crossed nicols. X-ray analyses, made by Dr. Thompson, gave good patterns of stannite and the intergrowth mineral. Unfortunately, the pattern did not fit any of the minerals which are known to exist in solid solution with stannite.” Photomicrographs in Campbell’s report are not unlike those in Harris & Owens (1972) and in Kissin & Owens (1979).
Muscovite: Goad (1980) described “green muscovite” in drill core. It is possible that from this observation has come the proposal to add “mariposite” and “phengite” to the minerals at the site. The whole subject of “green mica” is fraught with problems, and absent detailed mineralogical studies it would appear best to simply note the presence of muscovite.
Pyrargyrite?: Reported by “Minfile” to be present, with no supporting reference. Could this be the “ruby silver” reported by Gunning (1929, 1931)? Or might it be proustite? More work would be necessary.
Rutile: Reported only by Harris & Owens (1972).
Sericite: Reported only by Gunning (1931).
Silver: Reported only by Gunning (1931).
Stannite: First reported from the Snowflake workings by Gunning (1929, 1931), who described it as “zincian”, quoting an analysis performed at the laboratory of the Division of Mineralogy, Geological Survey of Canada which showed a zinc content of 7.72 percent. This material was studied by Campbell (1952), who noted in polished section the intergrowth of stannite with another phase (see comment above for kësterite), and said that an X-ray analysis, performed by Dr. R. M. Thompson showed a pattern matching that of stannite and a second which was unknown. Note that kësterite was only established in 1948 – see Mindat mineral data. Berry and Thompson (1962) reported an X-ray pattern for the Snowflake material, which they called “Zincian Stannite” – note that they did not appear to have access to any kësterite material, as it is not included in the Peacock Atlas. There things rested for a decade, until Harris and Owens (1972) studied “. . . a tin-rich lead-zinc-silver ore submitted to the Mineral Processing Division of the Mines Branch . . . .” (Canada Department of Energy, Mines and Resources). They determined that the so-called “stannite” was actually “a stannite-kësterite exsolution”. This has led to several other studies – interested readers should refer to, inter alia, Springer (1972); Kissin and Owens (1979); Kissin (1989); and Kissin and Owens (1989). Refer also to the Mindat Mineral Data page for more references. Finally, the Pacific Museum of Earth at the University of British Columbia has a specimen (Catalogue No. 406), which may be the material used by Thompson for his X-ray work.
Stannoidite: The only reference for this is that already posted, Anthony, et al. (1980), which does not appear to have any local significance, and the mineral has not been reported by any of the listed researchers. I would suggest this is not a valid species for the locality.
Tetrahedrite subgroup: First reported by Gunning (1929) as “grey copper” and confirmed by Harris and Owens who described it as “argentiferous”, but gave no further details.
Titanite: Reported only by Goad (1980), as occurring in drill core.
Wolframite: Reported only by Gunning (1931), and described as “. . . stubby dark brownish-black crystals . . . .”, but with no further data.

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Link to British Columbia Minfile:	082N 003

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References