Mining in the existing pit relies on Bucyrus Erie 60R 10 5/8-inch rotary drills to drill off 40-ft benches. The mine has five of these. Ore is hauled to the in-pit crusher (a Kobe 54×74- inch gyratory unit in Krupp-manufactured, semi-portable housing) by five 170-ton Lectrahaul trucks and 16 Euclids. Ore is moved from the pit floor via a tunnel conveyor inclined at 18 degrees through the pit wall to the concentrator at surface. The conveyor system was designed by Wright Engineers in 1985. Primary grinding is achieved by six 350-ton, semi-autogenous grinding (SAG) mills. Five 16.5×22-ft Allis-Chalmers ball mills provide secondary grinding. Mine Manager Chris Brown says the fifth grinding mill had been added only a few months ago. The rest of the concentrator incorporates conventional flotation with a rougher stage, three stages of cleaning, and column flotation for the final cleaning step. A separate flotation circuit recovers molybdenum.
The 18-year-old Island Copper mine, operated by BHP-Utah Mines (a wholly-owned subsidiary of Australia’s Broken Hill Proprietary Co.), produces 130 millon lb of copper in concentrate which averages 25.5% copper every year. The concentrates are shipped to the Orient.
]]>
Be the first to comment on "ISLAND"