MEXICO BAJA MINING CORP. of Vancouver has prepared a definitive feasibility study for its Boleo copper-cobalt project at Santa Rosalia, on Mexicos Baja Peninsula. Direct capital costs would be in the neighbourhood of US$407 million to build a mine and plant that would produce 55,750 t of copper cathodes, 1,535 t of cobalt cathodes and 6,400 t of contained zinc metal in each of the first four years of production.
Resources are sufficient for a 25-year project life. Proven reserves suitable for open pit mining total 11.1 million t at 2.3% CuEq and probable reserves total 6.5 million t at 1.75% CuEq. Proven underground reserves are 29.8 million t at 2.54% CuEq and probable reserves are 37.6 million t at 2.19% CuEq.
Both surface and underground mining operations are planned for extracting ore for the first 25 years at a full mining rate exceeding 3.1 million t/y. Approximately 68.0 million t of ore will be mined from underground operations and 9.0 million t from open pits. Approximately 18.8 million tonnes of limestone will also be quarried for use in the plant process.
The Boleo mineral processing plant will treat ore with a head grade of 2.2% Cu, 0.1% Co and 0.6% Zn by hydrometallurgical means. It will produce LME Grade A copper cathodes, high purity (greater than 99.8% Co) cobalt cathodes, and zinc sulphate monohydrate. A conservative ramp-up rate of four years is assumed before achieving design throughput of ore, however the run-of-mine ore grades are highest in these years and copper production will still reach the capacity of the electrowinning circuit by Year 3. Recovery of cobalt and zinc will commence in Year 2, allowing an accelerated construction schedule for copper production and a focused technical effort on the start-up of the copper circuit.
The process plant design includes a 2,400 t/d acid plant with a cogeneration facility to produce electrical energy from the burning of sulphur. It is expected that the acid plant will generate essentially all of the power requirements of the process and electrowinning plants as well as the desalinated water requirements. The leach circuit will utilize sea water. Average cash costs over the life of the mine are estimated to be US$0.70/lb of copper.
A quick check of the Baja website at www.BajaMining.com reveals photos of picturesque buildings in the nearby town of Santa Rosalia as well as pictures taken during test mining.