Canada Tungsten — Change to Underground Mining & Description of Mine-Mill Procedures

CIM Bulletin, Vol. 70, No. 784, 1977

W. W. Cummings, Chief Geologist, and D. E. Bruce, Metallurgist, Canada Tungsten Mining Corporation Ltd., Tungsten, Northwest Territories

Canada's only current tungsten producer started up in 1962 with a small open-pit mine on the Flat River, 130 air miles north of Watson Lake, Yukon Territory. The orebody was in a contact-metamorphic skarn zone and contained about 1.5 million tons of ore grading an estimated 247% W03 and 0.5% copper. Near the end of the open pit, a new zone was discovered on the lower limb of the same structure, and the decision to go underground was made in 1972 The new "E Zone" contains over k -million tons of ore grading an estimated 1.6% WOS and 0.23% Cu, and has been supplying the concentrator at about 175,000 tons/ year since late 1974. A continuing program, of change and up-grading is necessary in the conversion from a seasonal open-pit mine with limited life to an underground operation with twenty years of reserves. Changes are necessary in plant and services as well as the mine. Also, environmental protection requirements have changed from rudimentary to rigorous over the life of the operation. This paper sums up the changes in the operation since 1971 and outlines the changes yet to come.
Keywords: Canada Tungsten, Underground mining, Milling, Tungsten, Mine services, Blasting, Crushing, Classifying, Flotation, Talc flotation, Scheelite flotation, Gravity separation, Tailings.