Mission prospect, Hedley, Osoyoos Mining Division, British Columbia, Canadai

Regional Level Types
Mission prospect	Prospect (Abandoned)
Hedley	Unincorporated Community
Osoyoos Mining Division	Division
British Columbia	Province
Canada	Country

The Mission occurrence is located near the headwaters of Jamieson Creek, 4 kilometres south-west of the small unincorporated community of Hedley, or 38 kilometres west-southwest of Penticton, British Columbia, in the Osoyoos Mining Division. One report indicates that this prospect is located in theSimilkameen mining division.

There is a description of the property, including regional geology, on the British Columbia “Minfile” site, (as of 2014). Relevant portions are quoted below:
“An elongate mass of medium-grained biotite granodiorite of the Middle Jurassic Cahill Creek pluton extends northwest from the main intrusive body into argillite, siltstone and limestone of the Upper Triassic Hedley and Stemwinder Mountain formations (Nicola Group). The granodiorite is cut by a number of shear zones commonly striking at 030 and 060 degrees. Significant mineralization is contained along three principle shear zones, the Barnes, Walker and Winkler zones. The Barnes zone strikes 030 degrees and dips 70 degrees southeast. The zone has been traced for 240 metres and is between 3 and 5 metres wide. The Walker and Winkler zones extend southwest from the Barnes zone, both striking 060 degrees for 90 and 140 metres respectively, and dipping 80 degrees northwest and 85 degrees southeast respectively.

The granodiorite is altered in the shear zones to a white granular material comprised of quartz, sericite and orthoclase [no reference given], with minor chlorite (altered biotite) [see mineral discussion below] and traces of epidote and calcite. The zones contain disseminations, bands and lenses of sulphides forming between trace and 40 per cent of the altered granodiorite. The sulphides include pyrite, fine-grained arsenopyrite, dark brown sphalerite and minor tetrahedrite and chalcopyrite.”

Giles Peatfield Ph.D., P.Eng (Retired) comments:
There is no recorded production from this property. There are also no reported silver minerals, apart from small amounts of tetrahedrite (see below). Hedley (1937) reported assay data that appear to show a positive relationship between sphalerite content and silver grade.


Comments on the Minerals Reported:
Arsenopyrite: Reported by Hedley (1937) as “fine grained”, and by Lee (1947) as “coarse, euhedral”.

Boulangerite: First reported by Lee (1947), who at first thought it might be galena, but on the basis of etch tests discarded this hypothesis. He then conducted a series of microchemical tests led him to consider jamesonite, boulangerite, meneghinite, or semseyite. The mineral was finally conclusively identified as boulangerite on the basis of an X-ray determination by Dr. R. M. Thompson, then at the University of Toronto. This identification was subsequently published by Warren (1948), who was Lee’s supervisor for the work at UBC.
The Pacific Museum of Earth at the University of British Columbia has two specimens (catalogue #1943) of boulangerite with pyrite from this occurrence. As an interesting aside, Lee wrote that “Previous workers had listed arsenopyrite, pyrite, sphalerite, tetrahedrite, stibnite and an unidentified silver mineral as being the sulphides present in the deposit.” Unfortunately, he did not provide a reference, and I have been unable to find any further information. However, mistaking boulangerite for stibnite is not difficult – refer to a recent Mindat posting for the Nip And Tuck deposit in the Invermere, B.C. area for another example of this.

Calcite: Reported only by Hedley (1937) as “traces”.

Chalcopyrite: Hedley (1937) reported “a very little” chalcopyrite. Lee (1947) reported tiny inclusions in sphalerite, which were too small for him to analyze but which from his description sound like “chalcopyrite disease.”

Chlorite Group: Hedley (1937) mentioned “a little” chlorite in altered vein material.

Epidote: Hedley (1937) reported “traces” of epidote.

“Limonite”: Lee (1947) reported a reddish iron oxide with pyrite, which I have assumed to be limonite.

Mica Group: McKechnie (1969) reported green mica that he called “altered biotite”, but gave no further information. Several workers have described another mica as sericite, in altered vein material.

Pyrite: Reported by most workers on the occurrence.

Quartz: Lee (1947) gave a good description of two or more varieties of quartz in the deposit.

Scorodite?: Lee (1947) reported a “yellowish-green oxidation” product with the arsenopyrite; I have tentatively listed this as scorodite, but detailed work would be necessary to confirm this.

Sphalerite: Hedley (1937) made the point that sphalerite was “dark brown”. It does not appear to be a common constituent of the mineralized material.

Tetrahedrite subgroup: Hedley (1937) reported “a very little” tetrahedrite; Lee (1947) did not see it.

Other Databases

Link to British Columbia Minfile:	092HSE052

Other Regions, Features and Areas containing this locality

References