Davidson deposit, Omineca Mining Division, British Columbia, Canadai

Regional Level Types
Davidson deposit	Deposit
Omineca Mining Division	Mining Division
British Columbia	Province
Canada	Country

The following quote is from B.C. Government site “Minfile”- Minfile No. 092JNE 068:
“The showing area is underlain by Lower-Middle Jurassic Hazelton Group andesite and tuffs that are in turn overlain by Lower-Upper Cretaceous Skeena Group sediments. A large discordant and differentiated granodiorite sheet is intruded into the volcanic sequence. The Early Tertiary-Late Cretaceous (67-73 Ma) Hudson Bay Mountain stock is concealed and is estimated to be 550 metres thick. It is divided texturally from the upper to lower contacts as aplitic granodiorite, porphyritic granodiorite and granodiorite, respectively. The stock contains blocks of Hazelton volcanics traceable for hundreds of metres. Lamprophyre dikes crosscut both the granodiorite and Hazelton rocks. The metamorphism is due to the intrusion of the Hudson Bay stock and the associated intrusion of a rhyolite porphyry plug and radial quartz feldspar porphyry dikes. The rhyolite plug is oval shaped and at its upper contact are quartz stockworks and a high silica zone that crosscuts well defined chill and crenulate quartz band zones.
Veins hosting molybdenite and scheelite occur over three kilometres horizontally and are enveloped by radial base metal veins that extend beyond an eight kilometre radius. High-grade molybdenum zones occur in the lower portion of the differentiated granodiorite sheet and is (sic) an important lithological control on mineralization. The molybdenite mineralization occurs over a surface area of approximately 2.5 by 1.5 kilometres and a vertical distance of 2.1 kilometres. Strands of 0.2 per cent molybdenite appear over more than 600 metres vertically.
Molybdenite occurs in three modes: 1) early fine grained, hairline stockwork veins characterized by potassic alteration and relatively low molybdenum values; 2) domal sets of fine grained, banded quartz-molybdenite veins associated with phyllic alteration and high-grade assays; and 3) spectacular molybdenite crystals up to 5 centimetres in length occur in coarse grained quartz-molybdenite veins characterized by potassic alteration envelopes with high assays.
Scheelite occurs in quartz-magnetite-potassium feldspar veins formed prior to the coarse grained quartz-molybdenite veins. Scheelite also occurs as rare disseminations associated with andradite garnet, epidote and quartz assemblages formed prior to the fine grained hairline stockwork veins. Minor amounts of wolframite are found downdip from the granodiorite sheet.
Late-stage vein mineralization includes pyrite, chalcopyrite, sphalerite and carbonate. The source of the mineralizing fluids is thought to be the Hudson Bay Mountain stock due to its spatial relationship. The tungsten-rich zone generally straddles the upper 0.2 per cent molybdenum boundary.”
For details of various resource calculations for the deposit, refer to Minfile, No. 092JNE 068.
Further comments by Giles Peatfield regarding minerals reported:
“Scheelite-Powellite”: Kirkham (1967) described “scheelite-powellite”, and this nomenclature was repeated by Jonson, et al. (1968). Kirkham (1969, p. 59) stated that “Chemical and x-ray analyses show, however, that scheelite from the Hudson Bay Mountain district contains only minor Mo in solid solution.” Given this information, I have listed scheelite only.
Bismuthinite: Kirkham (1967) and Jonson, et al. (1968) both mentioned bismuthinite. Kirkham (1969), in a table (p. 76), mentioned bismuthinite from the 3500 level adit, “in a tungsten-rich vein near the limit of molybdenum deposition.”
“Tetradymite”: Kirkham (1969), also in a table (p. 76), mentioned tetradymite from the 3500 level adit, “in a tungsten-rich vein near the limit of molybdenum deposition.” This is only mention of tetradymite I have been able to find, but I have let it stand.
“mineral groups”: Several mineral groups, e.g. “epidote”, etc., have been mentioned but have no more definitive data. I have allowed these to stand, in quotes- Giles Peatfield

Giles Peatfield
BASc. (Geological Engineering) University of British Columbia 1966.
PhD Queen's University at Kingston 1978.
Worked for Texas Gulf Sulphur / Texasgulf Inc. / Kidd Creek Mines - 1966 to 1985.
Vancouver based consultant 1982 to retirement in 2016

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Link to British Columbia Minfile:	093L++110

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References