The Charcas mining district occupies the east-central part of the Mexican Central Mesa and is part of the Sierra Madre metallogenic province. Economic ore is found as replacement sulfurs in carbonates host rock. The ore mineralogy is comprised predominantly of calcopyrite (CuFeS), sphalerite (ZnS), galena (PbS) and silver minerals as diaphorite (Pb Ag Sb S).

San Martin lies in the Central Mesa between two major geologic provinces, Sierra Madre Occidental and Sierra Madre Oriental. The district’s most important mineral deposits are replacement veins and bodies generated in the skarn by Cerro de la Gloria granodiorite intrusion.

The majority of production from Santa Barbara district comes from quartz veins within faults and fractures. The north to northwestern trending veins is up to several kilometers long, dips steeply to the west and is 0.5 to 30 meters wide.

Santa Eulalia mineralization corresponds in its majority to ore skarns — silicoaluminates of calcium, iron and manganese with variable quantities of lead, zinc, copper and iron sulfides, located in the planes of crossings in the interstices of the silicates. Economic ore is found as replacement in the Limestone Glen Rose in the contact with dikes and sills and replacements in diabase sills. The mineralogy is comprised predominantly of sphalerite (ZnS), galena (PbS) and small quantities of pyrargyrite (Ag SbS ).

There are four types of ore deposits found in Taxco district. In o ........

IMMSA unit (underground mining poly-metallic division) operates five underground mining complexes situated in central and northern Mexico and produces zinc, lead, copper, silver and gold, and has a coal mine. These complexes include industrial processing facilities for zinc, lead, copper and silver. All of IMMSA’s mining facilities employ exploitation systems and conventional equipment. IMMSA’s principal mining facilities include Charcas, Santa Barbara, San Martin, Santa Eulalia and Taxco.

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.

Mining in San Martin is completed using a mechanized Cut and Fill mining method with rockfill and with tailings (hydraulic) and dry tailings. 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. San Martín has been testing the long hole stopping mining methodology after the operation resuming.

Santa Barbara includes three main underground mines (San Diego, Segovedad and Tecolotes). The mining operations at Santa Barbara ar ........

Charcas
Mineral processing is completed via conventional flotation processes with three concentrates being produced (in order of scale):
• Zinc concentrate;
• Copper concentrate;
• Lead concentrate.

The mineral benefit plant was built with the purpose of concentrating the metallic minerals of interest (zinc, copper, and lead) and has a nominal capacity to process 4,100 tons/day.

San Martin
Mineral Processing is completed via conventional flotation processes, including crushing, milling, flotation, filtration, thickening and conduction and disposal of tailings. The Minera San Martín unit has two processing plants or concentrators. Three concentrates are produced:
• Zinc Concentrate
• Copper Concentrate
• Lead Concentrate

Santa Barbara
The ore, once crushed, is processed in the flotation plant to produce concentrates. The lead concentrate produced is treated at a third party refinery in Mexico. The copper conce ........