Colquijirca
(Marcapunta)

Marcapunta is an underground operation that exploits arsenical copper ore in the District of Colquijirca, Province of Pasco, Region of Pasco. The mine forms part of the Colquijirca Production Unit, property of Sociedad Minera El Brocal (61.43% BVN), a subsidiary of Buenaventura.

13K Project: The mine’s production will be increased from 7,500 to 13,000 tons per day. This project will include the following components: construction of a 1.3-km tunnel; the extension of ventilation systems with six vents with an additional 3 m in diameter; installation of a mobile crusher and a tertiary crusher in Copper Plant 1. The mine is expected to reach a production of 55,000 tons of fine copper by 2017.

Geology: 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.

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

Metallurgy: 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.

Treatment capacity: The El Brocal processing plant has a total capacity of 20,000 MTD, which is shared by the ore from Marcapunta and Tajo Norte.

Note: As of december 31st of the year indicated.