December 31, 2004
The plant has treated 2,200,000 tonnes grading 1.52% Cu and 7g/t Ag, and has produced 61,000 tonnes of concentrate.
On the deposit area outcrops a volcanic sequence of the La Negra Formation, where diorite stocks intrusion took place, formed from the Las Luces porphyry, on the north side, and from the south Diorite, on the south side. Also the Tranquita dike exists. All these formations are affected by a system of faults which control the emplacement of a porphyry intrusion at the north zone, and have served as mineralization fluid channels. Mineralization appears in bodies joined to sub vertical hydrothermal breccias, and mantles emplaced at receptive porous levels of flow which extends toward the sides of the nourishing structures. The sulfide mineralization appears from 50 m depth where Chalcosin -Bornite association and some Chalcopyrite prevail.
The mine is an underground mine where sublevel open stopping is used as mining method. The mine has a 65,000 t/m-capacity flotation treatment plant. (Dec/04)
In 1994, the development of the underground mine and the treatment plant construction began.
In 1984, a mining company (Shell Minerķa) began an exploration program and as of 1991, after carrying out 35,000 m of drilling, the project was transferred to Citibank.
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