The Charcas district presents a complex magmatic history. The swarm dikes consist predominantly of monzogranite, granodiorite, and granite. They represent four distinctive magmatic pulses dated at 157, 50, from 48 to 45, and 30 Ma.

Two main types of mineralization are found at Charcas. IMMSA describes the mineralization as either veins or replacement bodies (in the form of skarn/mantos). The mineralization of Charcas is associated to fracture systems that strike at N65°W to N80°E and dip up to 70°NE and up to 60°SW. Near the Tiro General Mine, there is fissure-fill mineralization, which forms parallel to the contact between the intrusive and the limestones. Vein Leones is hosted in limestone, and the Santa Isabel vein is hosted in the intrusive and is characterized by reduced widths. The formation of the mineralized fissures is associated to normal faulting.

The Principal Fault (which runs parallel to the Temeroso intrusive stock boundary) cuts all the mentioned veins. Many replacement orebodies are reported to be occurring along the fault. El Rey and La Reyna replacement orebodies are generated by the Leones-Santa Isabel trend to the west of the Principal Fault. Parallel to the Temeroso intrusive contact is the Bufa Fault that controls other replacement mineralization.

Replacements occur as massive sulfide ore, breccia ore, and as banded white tiger ore (Levresse et al., 2015). The mineralization of the veins and the associated replacement ........

The Charcas complex includes three underground mines: San Bartolo, Rey-Reina and LaAurora.

Charcas is exploited underground by room and pillar with hydraulic cut and fill. The crushed ore is transported to the surface for processing in the flotation plant.

Mining is completed using a mechanized cut-and-fill mining method with rockfill. Ramps and levels are developed to provide access to the ore. Attack ramps are then driven to access each cut. The ramps and level development are performed using jumbos.

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