Caraiba Copper, Brazil

Mineracão Caraíba S.A., a privately owned company, operates the Caraíba copper mine in northeastern Brazil. The mine’s processing facilities include a heap leach circuit for copper recovery from oxide ores, and a milling and flotation circuit for production of concentrates from primary and secondary sulfidic ores. Copper in the pregnant solution from the oxide leach is recovered in a SX-EW circuit, while the sulfidic flotation concentrates are shipped to an outside smelter. In an effort to avoid the high shipping and processing charges associated with the treatment of the sulfidic flotation concentrates at an outside smelter, and to provide acid to the oxide leach circuit and utilize excess SX-EW capacity, Caraiba is evaluating the applicability of the GEOCOAT^® technology for the heap biooxidation and leaching of the flotation concentrates. In 2008, Caraiba constructed a reusable 1600 tonne, 50m x 40m engineered GEOCOAT^® heap pad, along with associated solution ponds and a bacteria incubation and inoculation system. Due to the world economic downturn in late 2008 and the lower copper prices, commissioning was delayed until December 2009. The demonstration plant will operate for approximately 6 months, and a decision to treat all of the sulfide concentrates through GEOCOAT^® will be made thereafter.