Pinos Altos Mine

 gold mine, silver mine

 Upload a photo

The Pinos Altos Mine is owned by Agnico Eagle commenced commercial production in November 2009. It is located on an 11,000-hectare property in the Sierra Madre gold belt, 285 kilometres west of the City of Chihuahua in the State of Chihuahua in northern Mexico. At December 31, 2010, the Pinos Altos Mine was estimated to contain proven and probable mineral reserves of 3.3 million ounces of gold and 92 million ounces of silver comprised of 44.2 million tonnes of ore grading 2.30 grams of gold per tonne and 64.78 grams of silver per tonne. The Pinos Altos property is made up of three blocks: the Parrena Concessions (19 concessions, 6,041.1 hectares), the Madrono Concessions (17 concessions, 873.3 hectares) and the Pinos Altos Concession (one concession, 4,192.2 hectares).

The Pinos Altos Mine is in the northern part of the Sierra Madre geologic province, on the northeast margin of the Ocampo Caldera, which hosts many epithermal gold and silver occurrences including the nearby Ocampo mining operation and Moris mine.

The property is underlain by Tertiary-age (less than 45 million years old) volcanic and intrusive rocks that have been disturbed by faulting. The volcanic rocks belong to the lower volcanic complex and the discordantly-overlying upper volcanic supergroup. The lower volcanic complex is represented on the property by the Navosaigame conglomerates (including thinly-bedded sandstone and siltstone) and the El Madrono volcanics (felsic tuffs and lavas intercalated with rhyolitic tuffs, sandy volcanoclastics and sediments). The upper volcanic group is made up of the Victoria ignimbrites (explosive felsic volcanics), the Frijolar andesites (massive to flow-banded, porphyritic flows) and the Buenavista ignimbrites (dacitic to rhyolitic pyroclastics).

Intermediate and felsic dykes as well as rhyolitic domes intrude all of these units. The Santo Niño andesite is a dyke that intrudes along the Santo Niño fault zone.

Structure on the property is dominated by a 10-kilometre by 3-kilometre horst, a fault-uplifted block structure oriented west-northwest, that is bounded on the south by the south-dipping Santo Niño fault and on the north by the north-dipping Reyna de Plata fault. Quartz-gold vein deposits are emplaced along these faults and along transfer faults that splay from the Santo Niño fault.

Gold and silver mineralization at the Pinos Altos Mine consists of low sulphidation epithermal type hydrothermal veins and breccias. The Santo Niño structure outcrops over a distance of roughly six kilometres. It strikes at 060 degrees azimuth on its eastern portion and turns to strike roughly 090 degrees azimuth on its western fringe. The structure dips at 70 degrees towards the south. The four mineralized sectors hosted by the Santo Niño structure consist of discontinuous quartz rich lenses named from east to west: El Apache, Oberon de Weber, Santo Niño and Cerro Colorado.