Gray Rock Mine, Truax Creek, Bridge River area, Lillooet Mining Division, British Columbia, Canadai

Regional Level Types
Gray Rock Mine	Mine
Truax Creek	Creek
Bridge River area	Area
Lillooet Mining Division	Division
British Columbia	Province
Canada	Country

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Moore et al. (2009) give quartz, stibnite, tetrahedrite, sphalerite, jamesonite, cinnabar and gold as the late-stage open-space phases of the veins.

The old Gray Rock mine is located at the head of Truax Creek, 10 kilometres south of Carpenter Lake and 11 kilometres south-east of Goldbridge, British Columbia.
The following quote is from B.C. Government site “Minfile”- Minfile No. 092JNE 066, current to 2019:
“The mineralized veins of the Grey (sic) Rock occurrence are hosted by the Mississippian to Jurassic Bridge River Complex (Group) metasediments-greywacke, hornfels, minor conglomerates, recrystallized chert breccia and silicified limestone and volcanics. The metasediments are complexly intruded by dykes of granodiorite, aplite, granite, quartz diorite and quartz latite; extensions of the Cretaceous to Tertiary Bendor batholith are found approximately 300 metres to the south. Quartz filled parallel fissures transect both metasediments and dyke rocks. The mineralized veins are found mainly in the metagreywacke. The quartz infillings in the dykes are generally barren.
There are three main veins and up to six in a parallel system, striking northeast and dipping 50 to 65 degrees southeast. The vein-fissures vary in width from several centimetres to 2 metres, and have numerous faulted minor offshoots. The main (#1) vein is continuous downdip for at least 123 metres, averaging 1 metre in width and is offset 35 metres by fractures. The mineralization occurs in lenticular masses and is constant throughout the length of the vein. Stibnite occurs as disseminations and streaks in the quartz gangue and as massive layers on the vein walls. Smaller amounts of pyrite, grey copper with associated silver, sphalerite, galena, arsenopyrite, tetrahedrite and fuchsite are found in the main #1 vein; #2 and #3 veins contain only discontinuous lenses of high grade stibnite.”
Comment by Giles Peatfield regarding the locality:
It should be made clear that Gray Rock is a less well known occurrence, well to the south of the mines with antimony-gold mineralization closer to Carpenter Lake – see for instance Congress (B.C. Minfile No. 092JNE 029), Lou (B.C. Minfile No. 092JNE 131) and Minto (B.C. Minfile No. 092JNE 075), among others.
Comment by Giles Peatfield regarding the references:
I have included the references for papers by Leitch, et al., (1991), by Maheux (1989) and by Moore et al. (2009). While all these have good regional geological information, it is important to note that none of them refers directly to the Gray Rock mine.

Comments by Giles Peatfield regarding some of the minerals listed:
Arsenic: Allen (1964) identified arsenic “. . . as small blebs in the quartz and realgar.” He gave no further information, and this mineral should be regarded as tentative.
Arsenopyrite: This was reported by O’Grady (1937), and said by Bacon (1955) to be “rare”.
Bournonite: Armstrong (196?) regarded bournonite as tentative, but gave a good summary of microscopic characteristics – he found the mineral to occur in galena. Allen (1964) found bournonite as “. . . reaction rim between galena and tetrahedrite.” Again, there was very little definitive information. Joyce (un-dated) mentioned bournonite as occurring in the veins, but did not say whence he acquired this information. I would regard it as likely, but tentative.
Cervantite? Goodman (1944) reported an antimony oxide, possibly cervantite, as a surface phenomenon. He based the identification on microchemical tests. Further examination was made of “. . . tails of a flotation test . . . .”, and spectrographic analysis by (then) Mr. R. M. Thompson showed antimony to be major, and interestingly enough arsenic to be present in trace amounts. Currie, et al. (1944) noted that “A small amount of oxidized antimony (cervantite) was noticed . . . .” in polished section. None of the other workers reported this mineral, and it should be regarded as tentative.
Cubanite: None of the early workers identified cubanite, but Joyce (undated) described it and described how it was collected. The mineral was positively identified by Dr. R. Boggs of Eastern Washington University. Photographs of cubanite specimens are attached to this posting.
Muscovite: Bacon (1955) described an apple green Cr-bearing muscovite. One should, however, be cautious – not all green muscovites are necessarily Cr-bearing.
Pararealgar: For details on this mineral, refer to Roberts, et al. (1980) and Bonazzi, et al. (1995).
Pyrrhotite: Allen (1964) described pyrrhotite as “. . . exsolution blebs in sphalerite (emulsion texture).”
Realgar: Reported by numerous workers on the deposit. The only question is given the apparent paucity of arsenic minerals, what was the source of the arsenic?
Tennantite?: O’Grady (1937) reported tennantite, but Goodman (1944) whose comment for tetrahedrite was that it was “Microscopically determined, the presence of copper, antimony, and silver, as well as the absence of arsenic, disproved the previous suggestion by Dr. O’Grady that the grey copper was tennantite.” The mineral is thus shown not likely to be present.
Wurtzite: This was reported by Joyce (undated), posted a photograph and noted that “On the same cubanite crystals which are epitaxic on tetrahedrite, there are tiny crystals of wurtzite epitaxic on the cubanite crystals.”

Mineral List

21 valid minerals. 1 (TL) - type locality of valid minerals.