The Property is located along the margins of the Sierra Madre Oriental physiographic province. The regional geology is comprised of platform and basin sediments that were formed during the Mesozoic era on top of Paleozoic and Precambrian basement rocks. The region has undergone compression resulting in complex folding, faulting and uplift. Mantos and chimney style mineralization are associated with the Horizontes horizon within the La Negra member of the Lower Cretaceous Tamaulipas Formation. Pliocene age intrusions are emplaced into the stratigraphy on a local scale. Locally, the Carrizal mine contains six mineral zones and the El Monte Mine contains eight mineral zones that are hosted in limestone and calcareous shales of the Las Trancas, Tamaulipas, and Soyatal formations. The mineral zones are characterized as high temperature carbonate replacement deposits that consists of silver, lead, zinc and copper rich semi-massive and massive sulfide bodies that occur in proximity to quartz-monzonitic to monzonitic intrusions and monzonitic quartz-feldspar porphyry dikes. Argentite, galena, sphalerite, and chalcopyrite are the dominant economic minerals in the mineral zones.

Deposit Type
The general characteristics of mineralization at the Zimapan property are consistent with polymetallic replacement deposits as described by Morris (1986) and Cox (1986), published by Bray (1995). The mineral zones are further characterized as high temperature, chimney-style ca ........

Underground open stope mining is the primary method used at the Carizzal and El Monte mines. Variations of this method includes cut-and-fill, long hole stoping, and sub-level stoping for sub-vertical to inclined bodies, and room and pillar mining for sub-horizontal bodies. Sub-level stoping are typically mined in 15.0 m to 20.0 m primary and secondary panels between the main levels. Cross-cuts from the underground workings are typically developed through the footwall waste rock. Material from development headings through waste rock is used to backfill exhausted stopes where required. Typical room and pillar height are approximately 5.0 m.

The dimensions of the access drifts and ramps are approximately 4.5 m high by 4.0 m wide while production drifts are similar or 3.5 m high by 3.0 m wide. Muck piles and waste rock piles are prepared by mechanized drilling and blasting methods and the material is removed from the active stopes by scooptram vehicles. Material is then loaded into 10 to 15-tonne haul trucks and transported to the El Monte plant through the Lomo de Toro access ramp. Mechanized equipment is powered by diesel.

The main workings and access are actively ventilated while cross cuts and stopes are passively ventilated by raises and vent shafts, and actively ventilation if necessary.

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Conventional sulfide flotation is the recovery method used at the El Monte plant. The ground material is mixed with water and collector chemicals and passed through two froth flotation circuits: a lead-copper bulk flotation circuit and a zinc selective flotation circuit. The slurry is then thickened and filtered to produce a lead, a zinc and a copper concentrate. The resulting lead and zinc concentrates are generally 10% in humidity while the copper concentrate is generally 11% in humidity. Approximately 90% of the water utilized in the process is recovered and reused. Tailings are gravity fed down gradient to the existing tailings pond. Overall, approximately 67% Ag, 64% Pb, 52% Cu and 70% Zn mineral is recovered from the three concentrates.