This is a high-sulfidation epithermal deposit with outcropping gold and silver mineralization in oxides, related to silicified breccia associated with a pervasive siliceous alteration. Below the oxides level, there is mineralization consisting predominantly of arsenical copper and, to a lesser extent, covellite and supergene chalcocite. This epithermal event overprints a skarn with retrograde alteration identified at-depth, with clean copper mineralization.

Geologically, the Tantahuatay deposits are located at diatremes or volcanic necks in a sequence volcano-magmatic hydrothermal predominant linked to the regional mineralized sector north of Peru. Tantahuatay consists of five areas of Au-Ag mineralization, contained in material of supergenic oxidation (Mirador Norte, Mirador Sur, Cienaga Norte, Cienaga Sur and Tantahuatay). We have also discovered that below the oxides level of the Cerro Tantahuatay area, there is a significant resource of Cu AuAg in pyrite-enargite ore (sulphides), which is present as disseminations and fracture fillings associated with advanced argillic alteration and multiphase breccia bodies.

The mining is performed in two pits in exploitation: Tantahuatay 2 and Ciénaga Norte. The hauling distances to the leach pad and the barren material deposit, in the case of Tantahuatay 2, are 2.4 km and 0.7 km; and in the case of Ciénaga Norte, 9 km and 0.7 km, respectively. The material is loaded using 3-m3 excavators and transported using trucks with a capacity of 20 m3.

The metallurgical process at Coimolache consists of leaching the ROM ore (obtained from blasting in the open pit) on the leaching heap using cyanide solution. Two processes are carried out in the plant: Merrill-Crowe (zinc precipitation) and ADR (adsorption, desorption, and regeneration using activated carbon). All of the production at Coimolache is turned into doré bars (gold and silver), which are later sold.