San Dimas carries out a continuous program of exploration to convert resources into reserves. The program usually involves more than 35,000 meters per year of diamond drilling and more than 20 kilometers per year of drifting including exploration, preparation and infrastructure.
Typical of epithermal systems, the silver and gold mineralization of the San Dimas district exhibits a vertical zone with a distinct top and bottom that has been termed the Favourable Zone. This Favourable Zone was deposited in a horizontal position paralleling the erosional surface of the LVG on which the UVG was extruded.
This Favourable zone at San Dimas is some 300-600 metres in vertical extent and can be correlated, based both on stratigraphic and geochronologic relationships, from vein system to vein system and from fault block to fault block. Using this concept of the dip of the unconformity at the base of the UVG, the team is able to infer the dip of the Favourable Zone and with considerable success explore and predict the Favourable Zone in untested areas.
Exploration is focused on the high grade zone of the Central Block and western extension of the veins through the Sinaloa Graben Block. A tunnel connecting the Central Block Block and Sinaloa Graben Block was completed in early 2010 that enabled more detailed exploration to be carried out and to provide the infrastructure to develop more than 20 new high grade veins. One of the high grade areas is between the Roberta and Castellana veins (more than six veins), where diamond drilling has indicated that extensions to the economic zone could reach more than 0.5 kilometre in length.