Gold and silver

Underground operation

Angaraes, Huancavelica

4,200 masl

Started in 1953

Julcani (100% BVN) the driving force behind Buenaventura, commenced its operations in 1953 in the District of Ccochaccasa, Province of Angaraes, Region of Huancavelica. It is an underground mine with silver in narrow veins. 

Geology: Julcani is a fracture-filling silver-bearing epithermal deposit with Ag-Pb-Bi-Cu-WO3 mineralization, hosted in a complex of dacitic/rhyolitic domes from the Tertiary. The most important system of structures runs NW-SE, followed by E-W and NE-SW. It is important to note the zoning, wherein the central part (Tentadora dome) exhibits an Au-Bi-WO3 ensemble that changes to Ag- Pb toward the edges. Historically, the most important mines have been Herminia, Nueva Herminia, Mimosa, and Manto. The Acchilla and Estela Mines are currently in operation. The minerals present include tetrahedrite, argentite, silver sulfosalts, galena, sphalerite, and chalcopyrite, with gangues of siderite, pyrite, barite, silica, and calcite.

Mining: Over the course of its history, it has had several areas of exploitation. Operations are currently underway at Acchilla and Estela, where there are eight levels, with the highest being 420 and the lowest being 710. The shafts are located in Acchilla. Exploitation is carried out using the conventional overhand cut and fill method. The waste is recirculated to the pits, and the excess material is transported to the barren material deposits on the surface. Mine water drainage is performed using pumping stations located near shafts 487 and 993, with maximum flow volumes of 120 l/s. There is an acid water treatment plant at Acchilla, with a capacity of 180 l/s.

Metallurgy: At Julcani, the ore enters via hoppers and is sent to the washing mill, the crusher, and then to the bar and ball mills. The process continues in the flotation cells, thickener, and press filter. Finally, a bulk lead and silver concentrate is obtained, while ore with low metal content is disposed of in the Acchila tailings pond.

Treatment Capacity: 600 MTD

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