The San Dimas mine is located on the border of the States of Sinaloa and Durango, some 125 kilometres northeast of Mazatlan in central west Mexico. The site is accessed via a 45 minute flight from either Mazatlan or Durango, or by road through a ten hour drive from the city of Durango. Most of the personnel and light supplies for the San Dimas mines arrive on regular flights from Mazatlan and Durango. Heavy equipment and supplies are brought in by road from Durango.
Tayoltita is the most important population centre in the area with approximately 8,000 inhabitants, including mining company personnel. The population outside the mining town is sparse.
Water for the mining operations is obtained from wells and from the Piaxtla River. Water is also supplied by San Dimas to the town of Tayoltita from an underground thermal spring at the Santa Rita mine.
Electrical power is obtained from a combination of San Dimas owned power systems and the Federal Power Commission’s supply system. San Dimas operates hydroelectric and back-up diesel generators which are interconnected to the Federal Power Commission system.
The San Dimas region is mountainous. Elevations range from 2,400 metres on the high peaks to 400 metres in the valley floor of the Piaxtla River. Pine, juniper and scattered oak trees grow on the higher ridges while the lower slopes and valleys are covered with thick brush, cactus and grasses. Mining, subsistence farming, ranching and timber cutting are the predominant activities in the region.
San Dimas consists of five ore zones or blocks: San Antonio West, Sinaloa Graben, Central Block, Tayoltita and Arana Hanging Wall block . The San Dimas properties are surveyed and contained in a contiguous block that covers an area of 22,468 hectares. All mine production is processed through the Tayoltita mill.
All of the San Dimas mines are underground operations using mechanized cut-and-fill mining methods. After milling, cyanidation, precipitation and smelting, dore bars are poured and then transported to refineries in the United States. Over the last ten years Wheaton River and then Goldcorp invested in a major capital program that has significantly upgraded tailings management, will increase production and achieve a lower cost structure in the future.
The San Dimas gold-silver deposit is one of the most significant precious metal deposits in Mexico in a very large (15 km x 15 km) mining district. Historical production from the San Dimas district is estimated at 11 million ounces of gold and 582 million ounces of silver, affirming it as a world class epithermal mining province.
The Tayoltita mine is the oldest operating mine in the San Dimas area. The main access is a 4.4 kilometre tunnel from a portal approximately three kilometres to the northeast of the Tayoltita mill site. The Santa Rita mine main access is by adit approximately three kilometres to the northeast of the Tayoltita mill site.