Deposit Types
The Chipmo mineralization is of hydrothermal type with quartz infill. This deposit can be classified as epithermal Au-Ag veins associated with tellurides, with intermediate and low sulfidation. These structures are located in calc-alkaline rocks that are rich in potassium (Sarpane Volcanic). Veinhosting faults appear to be deep and crustal (Villon, 2011)The major recognized structures are the Prometida, Nazareno and Pucara Sur veins and correspond to the N60°E system.
Mineralization
In general terms, mineralization in the area of Orcopampa is associated to calderas with subvolcanic intrusives, dikes in Miocene tuffs (Swanson, 1998); in the Ocoruro-Jaspe area, mineralized structures are related to the Sarpane complex, faults, and possibly to subvolcanic bodies with more than one event or pulses of mineralization.
Mineralization in Chipmo deposit is dominated by the occurrence of gold tellurides, mainly calaverite in high levels; petzite and hessite and native gold can be found in the central part. Copper sulfosalts and other gold-silver and bismuth tellurides occur subordinately. In general, mineralization is characterized by high Au/Ag ratios (>3) and low base metal concentrations, which are evident in the deep levels to the east. Its mineralogy is mainly composed of quartz in breccia, banded and replacement textures; there are also sulfides such as pyrite (leached), barite, gypsum, anhydrite and calcite. Alteration minerals inclu ........
