The porphyry-style mineralization at Quebrada Blanca is considered to be typical of an Andean porphyry copper–molybdenum deposit. Common features of this subset of porphyry-style deposits include:
- Large zones (>10 km2 ) of hydrothermally altered rocks that commonly grade from a central potassic core to peripheral phyllic-, argillic-, and propylitic-altered zones;
- Mineralization is generally low grade and consists of disseminated, fracture, veinlet, and quartz stock-work controlled sulphide mineralization. Deposit boundaries are determined by economic factors that outline ore zones within larger areas of low-grade, concentrically-zoned mineralization;
- Mineralization is commonly zoned with a chalcopyrite–bornite–molybdenite core and peripheral chalcopyrite–pyrite and pyrite zones;
- The effects of surface oxidation commonly modify porphyry deposits in weathered environments. Low pH meteoric waters generated by the oxidation of iron sulphides will leach copper from hypogene copper sulphides and form oxide copper minerals such as malachite, chrysocolla, and brochantite, and redeposit copper as secondary chalcocite and covellite immediately below the water table in flat tabular zones of supergene enrichment.
A north–south trending corridor, bounded by the West and El Loa Faults, is preserved in the Quebrada Blanca–Collahuasi area. The corridor includes the Paleozoic volcano–sedimentary sequence Collahuasi Formation, generally consisting o ........