El Soldado, located in Central Chile (32°38’S; 71°04W) 120 km northwest of Santiago, is the largest (>200 Mt @ 1.4 % Cu) of the known copper manto-type deposits in central Chile. Although structurally controlled and discordant at the scale of the mine, it is regionally strata-bound within shallow marine, bimodal calc-alkaline basalt - rhyodacite (extrusive- intrusive) rocks of the Lower Cretaceous Lo Prado Formation, which also contains marine carbonaceous shale and volcaniclastic sandstones. It is generally acknowledged that hydrothermal sulphide base metal deposits in the Andes obtained their metals and sulfur from calc-alkaline magmatic systems.

Several structurally-controlled orebody clusters occur within an area of ca. 2000 x 800 m, 600 m vertical, in a dilational fault jog within a large NS orogen parallel (sinistral) strikeslip shear fault system that was active in the Cretaceous. The orebodies are zoned with pyrite in outer halos or envelopes, followed inwards by zones with abundant pyrite-chalcopyrite, chalcopyrite-bornite and a bornite-chalcocite core with minor hematite in the higher levels and the chalcocite cores; pyrite is relatively more abundant at depth and in the northern half of the deposit.

Samples of massive pyrite and associated chalcopyrite and bornite, devoid of visible bitumen, were selected from the Valdivia Sur, Arauco Norte, Catedral and Morro orebody clusters, most from the pyrite-chalcopyrite halos such as those shown in, o ........

Currently, the deposit is exploited in an open pit, at an average height of 1,000 meters above sea level. The El Soldado pit is of a hillside type, very different from the ones we commonly know in the shape of an amphitheater.

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