Mount Isa Mines tetrahedrite as ore minerals along with common accessories pyrite, pyrrhotite, quartz, carbonates and graphite. Minor arsenopyrite, marcasite, chalcopyrite, valleriite, proustite, polybasite and argentite also occur. Original surface oxidized ore contained cerussite, anglesite and pyromorphite. Silver and zinc were removed from the surface oxidized zone and were deposited as supergene ore at a depth above the primary ore. Copper occurs in brecciated "silica-dolomite" rock. Primary minerals are chalcopyrite, pyrrhotite and arsenopyrite. minor amounts of cobaltite, marcasite, valleriite, chalcostibite, galena and others are reported. Smelter operations release sulfur dioxide emissions very close to the city of Mount Isa. The Mount Isa Mines
Lateritic nickel ore deposits the weathering mantle developed above ultramafic rocks. As such they tend to be tabular, flat and really large, covering many square kilometres of the Earth's surface. However, at any one time the area of a deposit being worked for the nickel ore is much smaller, usually only a few hectares. The typical nickel laterite mine often operates as either an open cut mine or a strip mine. Nickel laterites are a very important type of nickel ore deposit. They are growing to become the most important source of nickel metal for world demand (currently second to sulfide nickel ore deposits).