Summary:
The Caballo Blanco zinc, silver, lead mine, situated south of Potosi, is located in the Jayaquila – Victoria corridor, a 5-7 km north-south structural zone with three sectors, from north to south, the Colquchaquita, Reserva, and Tres Amigos mines. They are not described in the published literature. They are hosted by volcanic rocks of the Kari-Kari volcanic complex, with dimensions of 32 km north-south and 12 km wide, located on the SE side of the Los Frailes felsic volcanic field that covers an area of 8,500 km2 at altitudes of 4,000 – 5,200 masl. The history started with intrusion of small granitoids at about 25 Ma at Kumurana, at the southern end of the Kari massif, and Azanaques. These were followed by the formation of Kari at about 20 Ma that is interpreted to be a resurgent caldera with welded ignimbrite fill. Ash flows, domes and stocks formed in the Cebadillas episode at 17-10 Ma, including the Cerro Rico dome with Ag-Sn mineralization at 13.8 Ma (Zartman & Cunningham, 1995; Cunningham et al., 1996; Rice et al., 2005).
The rocks of the Kari complex are felsic, peraluminous, and rich in garnet, cordierite and tourmaline (Schneider, 1987).
Mineralization in its generality is characterized by being housed in philonian structures divided into three domain orientations:
1. Oriented at N 10° to 20° E, are Colquechaquita (Karina, Viviana, Camila), and some veins of Tres Amigos (Catalina, Milagros Este and Central);
2. Oriented N 10° to 30° W°; Reserve veins (Rosario, Wendy, Juanita and Blanquita), in Tres Amigos there is also within this system the vein (Ramo Catalina); and
3. Corresponding to veins of the Porvenir sector where they have an N-S orientation, corresponding to Reserva (Veta Rosita) and in Tres Amigos (Milagros veins).
General mineralogy is composed of quartz-pyrite-chalcopyrite and marmatite, sphalerite, galena, boulangerite (Tres Amigos) as primary minerals; as accessory minerals we have siderite, calcite and ankerite at the trace level.
The mineralogy is quartz, pyrite, chalcopyrite, marmatite, sphalerite, galena and boulangerite with minor siderite, calcite and ankerite.