Cerro Verde Project — Stage 1 "Copper — Oxides To Cathodes"

CIM Bulletin, Vol. 71, No. 798, 1978

Victor R. Eyzaguirre P., Production Manager, Minero Peru, Lima, Peru Roy Ellerman, Vice-President, Mining and Process Technology, and Lynton Gormely, Process Engineer, Wright Engineers Limited, Vancouver, B.C.

Cerro Verde is one of several large porphyry-type copper deposits in Southern Peru. The copper occurs as primary sulphides, with a significant oxide capping. The exploitation of the deposit has been correspondingly divided into two stages, the first consisting of copper production from oxides, and the second from sulphides.Minero Peru successfully started the Stage I plant in June of 1977 with the first production of electroron copper cathodes. This paper is essentially devoted to a description of the Stage I process, which can be summarized as follows: Ore is trucked to the primary crusher, where it is crushed to 225 mm and conveyed to a coarse ore stockpile. Ore withdrawn from the stockpile is secondary crushed to 65 mm, conveyed to a truck loadout bin, loaded into trucks and driven to the leaching pads. Ore is placed on the pads in lifts and sprayed with sulphuric acid solution to dissolve the copper. Copper-bearing solution forms a pond behind a dam at the lower end of each pad and is pumped from there to the solvent extraction plant. Copper is extracted from the leach solution into an organic phase and is then stripped from the organic phase to form a purified concentrated copper solution suitable for feed to electrowinning. In etectrowinning, the copper is finally recovered as cathodes suitable for sale as refined copper.
Keywords: Hydrometallurgy, Cerro Verde Project, Peru, Copper production, Crushing, Leaching, Pad leaching, Solvent extraction, Solution storage, Electrowinning, Cosecha solutions.