Summary:
Julcani is a large polymetallic deposit located in central Peru, which primarily produces silver and, as a byproduct, lead. The silver is mainly present in the form of sulfosalts in numerous veins with complex mineralogy. These veins are narrow and are hosted in domes of dacitic rocks, tuffs, breccias, and other tertiary volcanic rocks.
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.