The Las Cruces orebody, Seville Province, Andalucia, Spain.

The Las Cruces massive sulphide deposit is located near Seville, southern Spain, in a blind extension of the Iberian Pyrite Belt. Mineralisation extends down from the pre-Miocene erosion surface, along which there has been some mechanical transport of its weathering products. Below that surface is a boadly flat-lying zone of secondary enrichment, generally 50 to 75 m thick, rich in chalcocite and other secondary sulphides. Copper enrichment is the most important economically, and the zone is capped by oxidised and siliceous materials that concentrate gold and silver. Hypogene sulphides of normal type underlie the enriched zone, with the main sulphide body dipping concordantly to the north at 45 degrees. Rio Tinto's geological estimate of the secondary copper resource at the end of 1998 was 15 500 000 t averaging 6.1% Cu. They also estimated about 2 000 000 t of gossan oxides, averaging 5.1 g/t Au and 115 g/t Ag. Hypogene resources at that time were estimated at 4 500 000 t averaging 3.3% Cu and 20 700 000 t of polymetallic mineralisation averaging 4.2% Zn, 2.0% Pb and 0.8% Cu.
The Las Cruces massive sulphide deposit is located near Seville, southern Spain, in a blind extension of the Iberian Pyrite Belt. Mineralisation extends down from the pre-Miocene erosion surface, along which there has been some mechanical transport of its weathering products. Below that surface is a boadly flat-lying zone of secondary enrichment, generally 50 to 75 m thick, rich in chalcocite and other secondary sulphides. Copper enrichment is the most important economically, and the zone is capped by oxidised and siliceous materials that concentrate gold and silver. Hypogene sulphides of normal type underlie the enriched zone, with the main sulphide body dipping concordantly to the north at 45 degrees. Rio Tinto's geological estimate of the secondary copper resource at the end of 1998 was 15 500 000 t averaging 6.1% Cu. They also estimated about 2 000 000 t of gossan oxides, averaging 5.1 g/t Au and 115 g/t Ag. Hypogene resources at that time were estimated at 4 500 000 t averaging 3.3% Cu and 20 700 000 t of polymetallic mineralisation averaging 4.2% Zn, 2.0% Pb and 0.8% Cu.