Carmen de Andacollo copper mining operation is located in Region IV in central Chile at an elevation of 1,000 metres, approximately 350 kilometres north of Santiago, near the southern limit of the Atacama Desert.
Teck owns a 90% interest in the mine. Empresa Nacional de Minera holds the remaining 10%. In 2010, Camen de Andacollo sold an interest in future gold production to Royal Gold, Inc. equivalent to 75% of payable gold produced until cumulative production reaches 910,000 ounces of gold, and 50% thereafter.
Carmen de Andacollo is an open pit mine which produces copper in concentrates from the hypogene portion of a porphyry orebody. Copper cathode production from the supergene portion of the orebody is currently approaching completion.
The mineâ€™s life was recently extended by approximately 20 years with the achievement of commercial production at its new copper concentrator.
The Carmen de Andacollo mining property is located near the namesake city in Region IV in central Chile at an elevation of 1,000 metres, approximately 350 kilometres north of Santiago, near the southern limit of the Atacama Desert. Access to the mine site is on 55 km of paved roads from the city of La Serena.
Mining property covers 21 sq km, while the exploration property encompasses 206 sq km.
The majority of mine personnel live in the town of Andacollo, immediately adjacent to the mine, or in the nearby cities of Coquimbo and La Serena.
Mine site is located near the southern limit of the Atacama Desert at 1,000 m asl elevation. Climate is transitional between arid and Mediteraneean.
Geology and Mineralization
The Andacollo orebody is a porphyry copper deposit consisting of disseminated and fracture-controlled copper mineralization contained within a gently dipping sequence of andesitic to trachytic volcanic rocks and sub-volcanic intrusions. The mineralization is spatially related to a feldspar porphyry intrusion and a series of deeply rooted fault structures.
Beneath the supergene mineralization currently being mined there is a primary (hypogene), copper-gold sulphide deposit containing principally disseminated and quartz vein hosted chalcopyrite mineralization. The Hypogene Deposit was subjected to surface weathering processes resulting in the formation of a barren leached zone from 10 to 60 metres thick. The original copper sulphides leached from this zone were re-deposited below the barren leached zone as a copper-rich zone comprised of copper silicates (chrysocolla) and supergene copper sulphides (chalcocite with lesser covellite).
Sulphide (hypogene) mineral reserves at December 31, 2011 were estimated at 476.6 Mt grading 0.35% copper and 0.12 g/t gold.
Mining & Operation
Andacollo is a conventional truck and shovel open pit mining operation.
Mining of the oxidized part of the deposit would be ended in 2014, but the sulphide reserves are expected to last through 2035.
Andacollo is producing copper cathode from the supergene portion of the orebody. Oxide ore is transported to heap leach pads with a certain amount of lower grade ore being processed through dump leaching. Copper bearing solutions are processed in an SX-EW plant to produce LME grade A copper cathode. Copper cathode production is expected to end in 2014.
The mining operation's main focus is on the sulphide/hypogene mineralization that would be mined through 2035. The hypogene mineralization is subjected to a conventional metallurgical process - crushing, grinding, milling, flotation - that produces a copper and gold concentrate. Copper concentrates are trucked to the port of Coquimbo and from there to customers in Asia and Europe.
The concentrator plant was comissioned during late 2009.
In 2010, Royal Gold acquired a royalty interest in future gold production.