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.

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

Tajo Norte is an open pit operation that exploits zinc-lead-silver ores.

The drills make boreholes measuring 6.5 m deep and 6.74 m in diameter, in a 5 x 5 m grid. Once the terrain has been drilled, the explosives are placed, carrying out the blasting process to stir up the rock. An excavator allows for better selectivity of the ore to be transported to the concentrating plant, 8 km away, using dump trucks with a 35-MT payload. For loading, a power shovel with a bucket capacity of 10 m3 is used. The barren material is transported to the waste or waste ore deposit located 1.8 km away, using trucks with a 50-MT payload.

Marcapunta is an underground operation that exploits arsenical copper ore.

The Marcapunta mining method involves long drills, by sub-levels.

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 ........