Teck’s Red Dog MineThe Red Dog Mine in Alaska is an open-pit zinc and lead mine in Alaska. It is a grind and load-to-truck operation. A primary gyratory crusher and backup jaw crusher are sited at the exit from the pit. The ore is crushed to –150mm in the primary crusher. The mill grinding sequence consists of Fuller SAG and ball mills, which reduce the ore to 80% –65µm for primary flotation. Tower mills regrind to Zn 80% –22µm and Pb 80% –19µm. Treated water is used in the grinding circuit to minimize metal ions that inhibit flotation performance.
Flotation is carried out in Maxwell cells, retro-fitted with Outokumpu mechanisms, and in CESL column cells supplied by Canadian Process Technologies. On-stream analyzers, providing real-time assay information, control the flotation circuit. The result is a zinc concentrate at 55.2% Zn, 3% Pb and 137g/t Ag and a lead concentrate at 56.1% Pb, 11.7% Zn and 435g/t Ag. The concentrates are dewatered using pressure filters.
CONCENTRATE TRANSPORT
Concentrates are transported 83km by road to port facilities on the Chukchi Sea by Arrow Transportation using specially designed trucks. These haul 85t of concentrate in two side-dump trailers at an average of 50 loads/day year-round. At the port, two storage buildings are capable of storing 850,000t of concentrate from October to June. During the 100-day shipping season, Foss Maritime uses two barges to lighter the concentrates to vessels 5km offshore, owing to shallow inshore waters. Barge-based Caterpillar 988 loaders unload the concentrates. About one-third of the concentrates are destined for Cominco’s trail smelter in British Columbia."