The La Caridad deposit is a typical porphyry copper and molybdenum deposit as seen also in the southwestern basin of United States.

The La Caridad porphyry copper-molybdenum deposit occurs exclusively in felsic to intermediate intrusive igneous rocks and associated breccias. Host rocks include diorite and granodiorite. These rocks are intruded by a quartz monzonite porphyry stock and by numerous breccia masses, which contain fragments of all the older rock types.

Supergene enrichment, consisting of completes to partial chalcosite (Cu S) replacement of chalcopyrite (CuFeS ). The zone of supergene enrichment occurs as a flat and tabular blanket with an average diameter of 1,700 meters and thickness generally between 0 and 90 meters.

Economic ore is found as disseminated sulfurs within the central part of the deposit. Sulfide-filled breccia cavities are most abundant in the intrusive breccia. This breccia-cavity mineralization occurs as sulfide aggregates which have crystallized in the spaces separating breccia clasts. Near the margins of the deposit, mineralization occurs almost exclusively in veinlets. Ore minerals include chalcopyrite (CuFeS2), chalcosite (CuS) and molybdenite (MoS).

The La Caridad mine uses a conventional open-pit mining method.

Concentrator.
La Caridad uses state-of-the-art computer monitoring systems at the concentrator, the crushing plant and the flotation circuit in order to coordinate inflows and optimize operations. The concentrator has a current capacity of 94,500 tons of ore per day. Ore extracted from the mine with a copper grade over 0.30% is sent to the concentrator and is processed into copper concentrates and molybdenum concentrates. The copper concentrates are sent to the smelter and the molybdenum concentrate is sold to a Mexican customer. The molybdenum recovery plant has a capacity of 2,000 tons per day of copper-molybdenum concentrates. The lime plant has a capacity of 340 tons of finished product per day.

SX-EW Plant.
Approximately 757.7 million tons of leaching ore with an average grade of approximately 0.245% copper have been extracted from the La Caridad open-pit mine and deposited in leaching dumps from May 1995 to December 31, 2015. All copper ore with a grade lower than the mill cut-off grade 0.30%, but higher than 0.15% copper, is delivered to the leaching dumps. In 1995, we completed the construction of a SX-EW facility at La Caridad that has allowed processing of this ore and certain leach ore reserves that were not mined and has resulted in a reduction in our copper production costs. The SX-EW facility has an annual design capacity of 21,900 tons of copper cathodes.

The plant has three trains of solvent extraction with a nominal capacity of 2,400 cubic meters per hour and 94 electrowinning cells distributed in one single electrolytic bay. The plant has a daily production capacity of 65 tons of copper cathodes with 99.999% purity.