The mineral deposits of the Colquijirca district belong to a member of the family of porphyry copper (Cu) related deposits known as Cordilleran deposits. These types of deposits, which are generally formed in the upper parts of a porphyry Cu, are fundamentally characterized by prominent zoning with internal parts that are dominated by Cu and external zones where Zn, Pb and Ag are the main economically-interesting elements. In the case of the Colquijirca district, and specifically the area between the Marcapunta Norte and Colquijirca sectors, such zoning generally consists of three zones, which mineralogically consist mainly of enargite in the internal parts; chalcopyrite in the intermediate parts; and sphalerite and galena in the external parts (El Brocal, 2021).

Due to the advance of stoping over the years, the Colquijirca deposit is currently exposed, which facilitates the geological identification of the Tertiary basin. Asymmetric anticlines and synclines composed of carbonate and detrital rocks, attributed to the Eocene-Oligocene Calera Formation, can be found and considered as the host of mineralization. The deposit also presents volcano-clastic intercalations (ash tuffs), which is evidence of volcanic activity that was contemporaneous to sedimentation. In addition, with the review of 5 drillholes, the Shuco conglomerate sequence of the upper Eocene has been identified in depth, which underlies Lower Calera and overlies in depositional contact with the Mitú sa ........

Marcapunta, an underground mine that produces copper minerals. The underground mining methods are Sub level Stopping with cemented back fill and Room and Pillar with long holes. The pillars left in the ground are chain pillars that run along the entire mining direction and cover the mantle’s extension. This method varies depending on the mining sector. Recovery of ore pillars using cemented or detrital backfill is planned. El Brocal underground mine is located in the southern projection of the open pit. Underground operations 1.Marcapunta Norte 2.Marcapunta Centro 3.Marcapunta Sureste 4.Marcapunta Suroeste 5.Marcapunta Sur The underground mining methods are Sub Level Stopping with cemented backfill and Room and Pillar with long holes. The pillars left in the ground are chain pillars that run along the entire mining direction and cover the mantle’s extension. This method varies depending on the mining sector: - North Sector: the stope is 8 m wide, 28 m high, and length varies between 50 to 100 m; the pillar width has been set at 6 m. - South Sector, which includes the Southwest and Southeast Zone: the stope is 14 m wide, 28 m high, and the length varies between 50 and 100 m, with a pillar width of 6 m. Currently, El Brocal mine uses the long-hole Sub Level Stopping mining method and detrital fill in the most unfavorable sectors. Additionally, the height of overburden varies from 80 to 400 m depth. In the past, some sectors, located in the northeast sector of the mine, ha ........

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