EL BURRERO PROJECT; THE FIRST MANTO TYPE COPPER DEPOSIT IN THE ANDES OF ARGENTINE

D. SCHOMWANDT, G. RE KÜHL Y N. RUBINSTEIN

Keystone, Colorado

Congreso; SEG 2010 Conference; 2010

Society of Economic Geologists (USA)

El Burrero Project is located in the Malargüe fold and thrust belt in the Andean Cordillera of Mendoza Province, Argentina. It was mined in the beginning of last century and at present it is being explored by MINERA GEOMETALES S.A. The ore deposit is hosted by a Jurassic back-arc basin sequence composed by andesitic lavas (Río Damas Formation), interbedded with red sandstones and conglomerates (Tordillo Formation). The hypogene ore paragenesis consists mainly of chalcocite with minor chalcopyrite and galena and scarce bornite in a prehnite and calcite gangue; secondary minerals (malachite, azurite and supergenic chalcocite), are abundant. The mineralization appears discontinuously as stockwork and as infilling vesicles located exclusively in the upper part of the lava flows. Within the Project, there is evidence of mineralization that can be identified over an area of 500 hectares. Two mineralized levels were intercepted during the drilling program. Within the first 52 meters, there is an interval of 28 meters that presents an average content of 2.4% Cu and up to 55 ppm. of Ag. A second mineralized level, approximately 10 meters long, was also intercepted, bearing an average content of 3% Cu and up to 170 ppm.of Ag. The genetic characteristics and the age of this mineralization are similar to many Chilean “manto- type” copper deposits in the Southern Andes, being El Burrero Project the first deposit of this type described in Argentina. The reserves of this deposit could reach well over 50 million tons.