The chemical characteristics and development potential of magnesite deposits in British Columbia, Canada

摘要

Sediment-hosted Precambrian to Cambrian magnesite deposits in British Columbia are mostly located in the southeastern part of the Province. The only working mine is Mount Brussilof (Baymag Mines Copmpany Ltd) which contains high purity ore, with minor CaO, FeO, SiO_2 and Al_2O_3 as impurities. The mine supplies magnesite for the production of high quality caustic and fused magnesia. Other deposits are Marysville, Anzac, Driftwood Creek, Jab, Red Mountain, Topaz Lake, Cleland Lake, Dunbar Creek, Botts Lake and Invermere. Their magnesium-rich portions are mainly of magnesite. Impurities are more than at Mount Brussilof and are made up of pyrite, iron oxides, dolomite, calcite, chert, chlorite and mica. Microprobe analyses show that the magnesite from Mount Brussilof has extremely low Fe content and that all of the deposits in British Columbia contain magnesite with similar CaO/MgO/FeO proportions. Magnesite crystals from these deposits approach the composition of stoichiometric magnesite Assuming favourable market conditions, several of the other magnesite occurrences have good development potential. These deposits may be sources of raw materials for the production of refractory, electrical grade, environmental, agricultural and chemical grade magnesia products or magnesium metal. Beneficiation may not be required for electrical, environmental and agricultural applications.