Gold-silver mineralization found within the area of La Virginia is epithermal in character and typical of deposits in the Sierra Madre Occidental being hosted within andesite and basaltic andesite volcanic rocks of the Lower Volcanic Sequence and associated with dacitic, rhyolitic and andesitic intrusives. Mineralization is generally found along the regionally extensive subvertical major structures that are oriented NS to N10W or controlled locally along conjugate N40W structures (i.e. within the central Con Virginia Zone of the main district). Regional reconnaissance has resulted in identification of seven potentially significant zones containing gold-silver mineralization at various locations along the major structures.  The Company controls mineral rights over 34,000 hectares of ground and the La Virginia Zone is the first of the identified areas to be drill tested.   

Work within the main La Virginia district has been focused on seven kilometres of mineralized structures located in the eastern central portion of the claim block.  Target areas of high development potential include the El Campo Santo Zone, Con Virginia, and Las Huatas Zones, respectively, from north to south. Of the more than 50 drill holes reported to date, over half have encountered grades of mineralization that indicate the potential for underground development and production (see news releases dated October 14, 2011, June 28, 2011, and September 20, 2010). Historically gold and silver were mined from shallow pits and adits with high grade material being shipped to Nacozari, Sonora or processed on site using a primitive mill. Prior to Minefinders involvement in the project no modern day exploration drilling had been carried out on the zone.    

The mineralization is low sulfidation epithermal and occurs as quartz stockworks, veins and hydrothermal breccias controlled by high angle structures. Most of the drilling has been concentrated in the Las Huatas Zone where hydrothermal breccias containing greater than 6 mineralizing pulses have been identified. Assays from the hydrothermal breccias are typically greater than 5 grams per tonne of gold and 300 grams per tonne of silver locally ranging to over 30 grams per tonne of gold and 1,000 grams per tonne of silver. Zones of quartz stockwork surround the breccias and extend up to 30 metres into the hanging wall of the structure.  Gold and silver grades tend to be slightly lower in the stockwork zones though coalescing veining and metal rich pulses have resulted in bonanza grades locally. Mineralization drilled to date occurs as a mix of oxides and sulphides with a gradual decrease of oxidation with depth.   

Drilling at the project overall has identified a favourable horizon for bonanza gold andsilver grades that ranges from approximately 1,500 metres to 1,850 metres in elevation. Above this elevation the system transitions into lower temperature chalcedony veins and stockworks and below this elevation an increasing temperature regime is marked by a very slight increase in base metals and molybdenum. Areas of more intense mineralization may contain bonanza grades that have been observed to extend above and below the preferred elevations and are found where structural preparation is most intense.