The Brenda mine: The life of a low-cost porphyry copper-molybdenum producer (1970-1990), southern British Columbia

Special Volume, Vol. SV 46, No. 1995, 1995

Between 1970 and 1990 the Brenda mine milled 177 million tonnes of ore grading 0.169% Cu and 0.043% Mo from the calc alkalic Brenda stock which at the start of production was estimated to contain 159.3 million tonnes grading 0.183% Cu and 0.049% Mo (0.082 MoS.). The stock is a composite quartz-diorite/ granodiorite body of Jurassic age which intrudes Upper Triassic sedimentary and volcanic rocks of the Nicola Group. The initial extraction rate of 21 500 tonnes per day was gradually increased to 30 000 tonnes per day in 1986 to allow the extraction and processing of lower grades at a profit. A stripping ratio of 0. 6:1 was attained over the life of the mine. Operating costs in 1989 were $4.39 per tonne. Reclamation of the site included the contouring of all waste rock piles, seeding of all tailings pond slopes and the pumping of tailings water back into the open pit. The pit has the capacity to contain all the run off from the tailings pond and waste piles until the year 2003. The excellent environmental closure plan meets all provincial and local requirements. Brenda's efforts in the human resources field make it a benchmark for the mining industry. When closure was announad in 1987, Brenda instituted a human resources program which was well received by the employees and general public. This core of the program was based on providing pertinent information about closure, job relocation and environmental reclamation programs.

Mots Clés: Brenda Mine, Porphyry, Molybdenum, Copper, Economics, Low-cost, Human resources