El Peñón is classified as a low- to intermediate-sulphidation epithermal gold-silver deposit associated with steeply dipping fault-controlled veins emplaced following rhyolite dome emplacement. Gold and silver mineralization consists of disseminations of electrum, native gold and silver, acanthite, silver sulphosalts, halides, and accessory pyrite occurring with quartz, adularia, carbonates, and clay minerals. Epithermal deposits represent shallow parts of larger, mainly subaerial, hydrothermal systems formed at temperatures as high as about 300°C and at depths from about 50 to as much as 1,500 m below the water table. Analogous epithermal gold-silver deposits set in an extensional-transtensional, continental-margin arc are the Comstock Lode in Nevada, Martha Hill in New Zealand, Peñasquito in Mexico, and Hishikari in Japan.

El Peñón is located in the Central Depression (also known as the Central or Longitudinal Valley), that extends for 650 kilometers from the Chile-Peru border in the north to south-central Chile in the south. In the Atacama Desert, this valley corresponds in part to a Late Cretaceous to Paleogene volcanic belt that separates the Mesozoic magmatic arc, exposed in the Coast Mountains located to the west, from the Paleozoic and Triassic volcanic and sedimentary assemblages of the Domeyko Cordillera to the east. The Late Cretaceous to Eocene volcanic and intrusive rocks within the Central Depression consist of an alkali-enriched calk-alkaline bimodal ........

Ore from underground mines have recently been - and will continue to be - the main source of feed for the El Peñón mill. All underground mining operations are carried out by Yamana, while the open pit mining operations, representing only a very small proportion of the production over the LOM, are carried out by a contractor.

The El Peñón mine (El Peñón) is an underground and open-pit gold-silver mine located in the Atacama Region of Chile, approximately 165 km southeast of the city of Antofagasta.

The major assets and facilities associated with the mining operations at El Peñón are listed as follows:
• Mine and mill infrastructure including office buildings, shops, laboratories, stockpiles, tailing storage facility, and equipment.
• Campsite/housing facilities.
• Facilities providing basic infrastructure to the mine, such as access roads, electric power distribution systems connected to national power grid, water treatment and supply and sewage treatment.
• Underground infrastructure including portals, access ramps, ventilation raises, maintenance shops, and mobile fleet equipment.
• The open-pit infrastructure including haulage roads, ramps, and mobile fleet equipment.

Ore from underground mines have recently been—and will continue to be—the main source of feed for the El Peñón mill. Ore is sourced from one small active open pit mine (Chiquilla Chica) and from five of the seven major underground mining zones.