Mineralogy and Mineral Chemistry of the Au-Ag-Te-(Bi-Se) San Luis Alta Deposit, Mid-South Peru

A mineralogical and mineral chemistry study was carried out in the San Luis Alta telluride-rich gold deposit, mid-south Peru, to contribute towards determining its formation improving ore processing. The mineralization is considered an intrusion-related deposit located Arequipa segment of Coastal Batholith. occurs quartz veins hosted diorites granodiorites from Tiabaya Super-Unit. These are sulfide-rich deep areas contain abundant iron oxides. Sulfides mainly pyrite with minor chalcopyrite galena. Native telluride minerals abundant. Mineral determined using electron microprobe. mineralogy classified into four stages. Gold three last stages either large grains, visible naked eye, or, more frequently, grains less than 10 µm. appears as encapsulated pyrite, Fe oxides, filling fractures. first stage characterized by deposition massive which does not gold. During second stage, hessite, calaverite, petzite altaite formed. Additionally, Bi-tellurides, volynskite, rucklidgeite, kochkarite tellurobusmuthine, Some these occur blebs suggesting that a Bi-Te-rich melt formed ore-forming hydrothermal fluid transported Au Ag elements. This followed fracturing event tellurobismuthite, tetradymite montbrayite precipitated. In supergene replacement covellite, bornite goethite. Te-Bi do appear this but selenium amounts. Chlorargyrite iodargyrite associated