The San Martín gold-silver district hosts classic, medium-grade gold-silver, epithermal vein deposits characterized by low sulphidation mineralization and adularia-sericite alteration. The San Martin veins are typical of most other epithermal silver-gold vein deposits in Mexico in that they are primarily hosted in the Upper Cretaceous black limestone and calcareous shales of the Soyatal-Mexcala Formation. Tertiary Lower Volcanic series of rhyolite flows, pyroclastics and epiclastics, overlain the sediments.

Mineralisation is generally made up of breccia that commonly is concordant with a limestone/shale contact (in the San Martin and San José areas) which forms the relatively steeply dipping “Tronco” and “Mantos” oreshoots, these veins contact the younger volcanic flows (dacite and ignimbrite) where they have formed the more horizontal portions of the deposit. The mineralized economic breccia grades from 30 g Ag/t to 250 g Ag/t. Exploration has been concentrated along the NE trending breccia zone however evidence of a northerly trend in area 30 and 31 leads to suspect possible other structures together with 2.0 g Au/t to 30 g Au/t over widths that vary from 1.5 to 17.0 m but averaging 4.0 m.

Mineralization at San Martín occurs in association with an epithermal low sulphidation, quartz-carbonate, fracture- filling vein hosted by a structure trending approximately N40°- 60°E, dipping to the 50° to 90° to the southeast.

The San Martin structur ........

Mine production operations are in two distinct underground zones and one under one small open pit operation. Current mining is from zones, which are contiguous to, or nearby, earlier mined out areas.

The two underground zones are known as San José II and San Martín, while the open pit is the near surface remnants is now a closed operation. Production operations have been underway at the San Martin mine since May 1994. On top of the big breccia-vein the structure becomes a manto-like. Here the Cuerpo 28 and Cuerpo 29 orebodies have been exploited partially since 1998. A set of faults crosscut the structure and thrown down the continuous oreshoot and split it into several segments where Cuerpo 30 and Cuerpo 31 have been found. In 2001 the exploration of high-grade gold bodies called "Mantos" began. The first of these oreshoots was the Body 28.

The orebody geometry and geotechnical attributes of the ore and host rocks, in both underground zones, resulted in the selection of mechanized, trackless, room and pillar stoping, with post waste rock backfill and a poor mix of waste and cement, as the most suitable mining method for ore extraction. Ore recovered from these operations is hauled to surface by truck to the mill infrastructure, where it is crushed and milled.

The San Martin underground mine is accessed through a tunnel located at the 2,050-meter level.

Since 2007, SIM (Starcore International Mines) has been in control of the day ........

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