Mercator Minerals has reported the results of an optimized feasibility study that confirms development potential for what it terms a robust, large-scale, low-cost copper mine at its El Pilar project in Sonora, Mexico.
Proven and probable mineral reserves at El Pilar total 230.2 million mt grading 0.313% total copper and containing 1.6 billion lb of copper. The feasibility study outlines a 12-year mine life at an average production of 73 million lb/y of copper cathode, including an average of 78.7 million lb/y during the first five years. Processing of surface-mined ore would be by copper leaching and solvent extraction/electrowinning (SX/EW).
Initial capital to develop the project, excluding working capital, is estimated at $245 million. Average total cash operating costs are estimated at $1.37/lb of payable copper over the life of the mine and $1.27/lb during the first five years of operation.
Contract mining is planned for the preproduction period and for the first two years of operations, followed by owner mining for the remainder of the mine life. Mining and stacking of run-of-mine ore is projected to average 52,000 mt/d over the life of the mine and 49,000 mt/d during the first five years of operation. The overall strip ratio for the project is 1.95:1 waste to ore.
The project is designed to be an open-pit operation using conventional drilling, blasting, loading by diesel hydraulic shovels and truck haulage. Run-of-mine leach ore will be mined and stacked on a leach pad. Copper cathode will be produced from the oxide copper ore by acid leaching and SX/EW processing. A majority of the power required by the project will be produced as a by-product of a sulphur-burning acid plant, with backup and additional power requirements supplied by a power line connecting to the national grid.