The Colquijirca mine consists of three important polymetallic deposits: (1) Tajo Norte–Smelter, which contains zinc, silver and lead; (2) Marcapunta, which contains an auriferous mineralization in breccia oxides and an arsenic copper enargite mineralization as a continuation of the mineralized mantles of the Marcapunta Norte mine; and (3) San Gregorio massive zinc deposit, which contains zinc.

The Colquijirca deposit (Tajo Norte) is structurally located within asymmetric synclines and anticlines, whose flanks are Principal-Mercedes-Chocayoc-La Llave-La Pampa; and stratigraphically located in the Calera Formation (Lower Tertiary-Eocene), middle and upper members. The base metal zone (Zn + Pb-Ag) is the outermost halo of mineralization (cordillera-type) and, by volume, the zone of greatest economic importance. Its mineralogy consists of sphalerite and galena as vein ores, which occur as fracture filling and cavities, disseminations, and massive replacements. The gangue consists of pyrite, specular hematite, magnetite, kaolin, barite, siderite, ankerite-dolomite, and fluorite, less commonly. All of them occur as fracture filling and cavities. Native silver as filigree in cavities, and in association with siderite, has been observed near the transition zone. It is also possible to observe the occurrence of chalcopyrite-galena-dickite as filling in fractures and replacement zones.

At Marcapunta Norte, mineralization is stratiform, in both the mineralized blankets emplaced in the limestone of the Calera Medio Formation, and in the mineralized breccia located in the unit below said formation. The vein of ore consists of a massive replacement of sulfides and the filling of open spaces, for which reason it has been classified as a cordillera deposit tied to the Marcapunta volcanic complex. Mineralization consists of a vein of arsenical copper (enargite) with Ag-Au values, with gangues of pyrite, quartz, and alunite.

San Gregorio is located four kilometers south of the Colquijirca mine and consists of carbonate-hosted epithermal zinc-lead deposits.

The Colquijirca (also known as Tajo Norte) and Marcapunta Norte mines are wholly-owned by El Brocal.

The mining method in the Marcapunta mine (Underground) is sub level stoping with long pillars and backfill. This method is used to mine the Copper mantle that has an ore thickness up to 60 m. Mining is made by contactor with its own equipment. The equipment used for development are 2 arm jumbos with 6 yd3 underground loaders. The equipment used for production includes S7 top hammer Simbas with 6 yd3 underground loaders with remote control. Ore haulage to surface is done with 12 m3 15 m3 tipper trucks. Ore is taken to the process plant with 15 m3 and 20 m3 tipper trucks. In 2021, we are planning to use 9 yd3 underground loaders and in the hole hammer. Bench height is also being optimized in new zones from 20 m to 30 m.

Meanwhile, the mining method in Tajo Norte is an open pit. It is a conventional truck and shovel operation, through a contractor. The height of a workbench is 6 m and the equipment used includes DM45 and DML drilling rigs. Loading are by hydraulic excavators EC950E (5.6 m3) and 374D (4.6 m3) and hauling is by G500 B8X4 trucks (24.5 m3). For 2021 we are planning to use 8 excavators and 48 trucks. To maximize mine production, Tajo Norte mine employs a fleet management system that supports the transmission and receipt of data across the mobile fleet, and supports the collection of data which is input directly by equipment operators.

The ore from Marcapunta is treated in Plant 1, which uses the selective flotation process to achieve the concentration of the economic Cu mineralization. The concentrating plant is located in the Community of Huaraucaca, and includes the crushing, sorting, milling, conditioning, flotation, and filtering processes, as well as the respective tailings storage yards. Given the equipment characteristics and layout, the plant has the ability to beneficiate the copper ore from the Marcapunta Norte Mine. It has direct access to a railway, which is used to transport the concentrates to the port of El Callao.

The ore from Tajo Norte is treated at Plant 2, which uses the selective flotation process to achieve the concentration of the economic mineralization. It includes the crushing, washing, sorting, milling, conditioning, flotation, and filtering processes, as well as the respective tailings storage yards. Given the equipment characteristics and layout, the plant has the ability to b ........