J & L Au deposit, Revelstoke, Revelstoke Mining Division, British Columbia, Canadai

Regional Level Types
J & L Au deposit	Deposit
Revelstoke	- not defined -
Revelstoke Mining Division	Division
British Columbia	Province
Canada	Country

Stratabound carbonate-hosted lead-zinc mineralization, overprinted by a shear zone-hosted orogenic Au-Ag-Pb-Zn polymetallic mineralization.

The J & L property is located at the confluence of Carnes and Mckinnon creeks, approximately 32 kilometres north-east of Revelstoke; Revelstoke Mining Division.
The J & L deposit has had exploration activity for almost a century, including underground workings, resource estimation, and extensive metallurgical testwork. There is an extensive write-up available on the B.C. Government site “Minfile”- Minfile No. 082M 005, to which interested readers are referred. The following quotation from Minfile gives a capsule summary of the deposit characteristics:
“The main zones of mineralization on the J & L property are hosted by Hamill Group metasedimentary and metavolcanic rocks. These rocks are interlayered, or in possible fault contact elsewhere on the property, with the Early Cambrian Mohican and Badshot formations and the Lower and Upper Index formations of the Cambrian and younger Lardeau Group. Minor diorite, lamprophyre and amphibolite intrusive rocks are also present.
The Hamill Group consists of impure quartzites, limestone, phyllites, chloritic and sericitic quartz-mica schists, minor chert and graphitic schists. Chloritic and sericitic phyllites are developed throughout the sequence and constitute the bulk of the lithologic sequence hosting the deposit. They are gradational in composition both laterally and vertically from chlorite-rich to sericite-rich, making subdivision difficult. Quartz-rich and quartz-poor mica schists are also highly variable in composition and are prominent in the hanging wall. Sericite and quartz-sericite schists are associated with most mineralized zones. Iron staining is common in sections adjacent to mineralization and forms a narrow alteration envelope with sericite, chlorite and sulphides.
A typical section in the footwall of the main sulphide zone comprises quartz-chlorite and quartz-sericite phyllites and schists, quartzites and limestone. In the immediate footwall of the massive sulphides, the quartzites and pelitic rocks are usually overlain by two distinct carbonate units. The lower unit is a massive banded medium to dark grey limestone, which ranges in thickness from a few metres to more than 20 metres and contains little or no mineralization. It is overlain by a dark grey graphitic or carbonaceous limestone, which averages between 1 and 2 metres in thickness and contains discontinuous wispy laminations of yellowish brown crystalline sphalerite. The unit is locally silicified, has a cherty texture and is commonly cut by irregular and deformed carbonate veins and minor quartz veinlets, which may also transect the adjacent massive sulphides.
In the hanging wall, the sulphide body is normally in contact with sulphide-rich sericitic schists or phyllites of variable thickness; locally it may contact sphalerite-pyrite bearing carbonaceous limestone. Further into the hanging wall, quartzite or micaceous rocks may be interlayered with minor limestone and disseminated sulphides, which gradually decrease in abundance, giving way to phyllitic rocks with only trace amounts of disseminated pyrite.
The rocks within the main zone of the deposit are extensively deformed. They generally strike northwesterly 320-325 degrees, with an average dip of about 55 degrees to the northeast. The entire sequence is strongly to intensely sheared and most individual units are transposed. Sulphides exhibit sheared, cataclastic and weak mylonitic textures. Detailed underground mapping suggests that four or possibly five phases of deformation have affected the main zone sulphide sequence. The most prominent folds are tight to isoclinal, generally upright, with variable plunges trending northwesterly, parallel to regional structural trends. Stratigraphic and structural studies of the main zone suggest that the deposit has a moderate plunge to the southeast.”
Comments by Giles Peatfield regarding minerals reported:
There is an extensive list of minerals reported for the J & L deposit and its enclosing rocks. I have provided comments for several of the less common or abundant ones, some of which have been reported by only one or in some cases two workers.
A special note regards the work of Ivan Stairs. According to Pegg (1983, p. 34), “Ivan Stairs of Bathurst, N. B. also had polished section work done while Westairs Mines Limited [of which Stairs was president] controlled the area.” This would be in the period 1962-1967. I can find no record of who did the examination, although there is some speculation that it was done at CANMET in Ottawa. Stairs later prepared a report for Selco, dated 22 March 1982, listing the results of this examination. I have accepted the minerals in the Stairs report as valid for the locality.
Albite: This was reported by Harris (1982), in thin section.
Anglesite: This was reported, as an alteration of galena, by Rae (1941) and by Morton (1941), based on polished section examination. No subsequent workers reported the mineral, but it seems reasonable.
Apatite: This was reported by Harris (1982), in thin section.
Acanthite: This was reported in polished section by Stairs (1982), as argentite. No other workers reported acanthite.
Biotite: This was reported by Harris (1982), in thin section examination.
Bornite: This was reported by Stairs (1982) in polished section. No other workers reported bornite.
Boulangerite: This was reported by Stairs (1982) in polished section. No other workers reported boulangerite.
Bournonite: This was reported by Benson (1943) and by Pollock (1948), based on polished section examination, and by Ixer (1984), in polished section study. It is not clear whether or not Ixer used EDAX analysis to confirm bournonite.
“Chlorite”: This was reported by Harris (1982), in thin section examination.
Covellite: This was reported by Rae (1941) and by Morton (1941), and confirmed by Harris (1982) in polished section.
Dolomite: This was reported by Harris (1982), in thin section examination.
Fluorite: This has been reported on the Mindat site for J & L. It has not been reported by any of the workers I have data for; possibly it comes from the Chinese report.
Gold: Native gold, as microscopic grains in polished section, was reported by Stairs (1982) and by Ixer (1984).
Hematite: This was reported by Harris (1982), in thin section examination.
Jamesonite: This mineral, misspelled as “jamiesonite”, was reported by Stairs (1982) in polished section. No other workers reported jamesonite.
Molybdenite: This was reported by Ixer (1984), in polished section study. It is not clear whether or not Ixer used EDAX analysis to confirm molybdenite.
Muscovite: This was reported only by Pegg (1983).
Opaline silica: This was reported by Harris (1982), in thin section examination.
Proustite: This was reported by Stairs (1982) in polished section. No other workers reported proustite.
Pyrargyrite: This was reported by Stairs (1982) in polished section. No other workers reported pyrargyrite.
Scorodite: This was X-ray confirmed by Harris (1982).
Siderite: This has been reported on the Mindat site for J & L. It has not been reported by any of the workers I have data for; possibly it comes from the Chinese report.
Silver: Native silver, as microscopic grains in polished section, was reported by Stairs (1982). No other workers reported native silver.
Stannite: This was reported by Stairs (1982) in polished section. No other workers reported stannite.
“Sulfosalts”: At least two unidentified Pb-Sb or Pb-Sb-As sulfosalts were reported by Ixer (1984). Reference should be made to his report (in Pegg & Grant, 1984) for details.
Sylvanite: This was reported by Stairs (1982) in polished section. No other workers reported sylvanite.
Talc: Talc was reported by Gunning (1929).
Tennantite: This was reported by Stairs (1982) in polished section. No other workers reported tennantite.
Tetrahedrite: This has been reported by numerous workers; Ixer (1984) described it as “argentiferous”.
Titanite: Harris (1982) reported “possible sphene” in thin section examination.
Tourmaline: Tourmaline (precise species not given) was reported by Harris (1982) in thin section.
Zircon: Zircon was reported by Harris (1982) in thin section.

Other Databases

Link to British Columbia Minfile:	082M 003

Other Regions, Features and Areas containing this locality

References