The Antamina copper-zinc mine is located in the Andes Mountains of Peru, approximately 285km north of Lima in the Department of Ancash. The elevation of the mine is 4,300m above sea level.
The Quechua word «anta» means copper and gave birth to the name “Antamina”, or copper mine.
In 1860, the Italian sage Antonio Raimondi, documented the properties of the Antamina ore deposit in his emblematic work entitled El Perú, published in six volumes between 1874 and 1913. The ore deposit site was forgotten for decades and it was not until 1952 when Antamina was incorporated into the mining project exploration portfolio of the Cerro de Pasco Mining Company.
During the 1970’s Antamina was transferred to the Government and stayed there until 1996. That year, following a privatization process, the site was acquired by Canadian mining companies Rio Algom and Inmet. These companies founded a subsidiary, Compañía Minera Antamina S.A. The mine was brought into production by a joint venture comprising the Canadian companies, Noranda Inc (33.75%) and TeckCominco Ltd. (22.5%), Australian-UK-based BHP Billiton (33.75%) and the Japanese firm, Mitsubishi Corp. (10.0%). The subsequent merger between Noranda and its subsidiary, Falconbridge, and the acquisition of Falconbridge during 2006 by Xstrata brought Noranda’s holding into Xstrata’s portfolio.
During the mid-1990s, the Antamina deposit was considered to be the largest undeveloped copper/zinc orebody in the world.
Construction began following the completion of a feasibility study in
Antamina is a polymetallic skarn orebody with a regional structural trend parallel to the Andean Cordillera Trend. Major geological faulting and associated jointing was intruded by a multi-phased quartz-monzonite porphyry about 9.8Ma, resulting in a large area of intrusives being in contact with the older Jumasha limestone Formation.
The calcic skarn thus produced was mineralised by extensive hydrothermal solutions, forming at least six distinctive ore zones. Adjacent to the limestone contact, copper occurs mainly as chalcopyrite. Zinc and bismuth occur in any rock type but are generally found in the green garnet contacts with limestone, marble and hornfels, where lead is also present. Molybdenum is present in the intrusive core, with silver found in any of the skarn lithologies, associated with both ore types, while copper ore also contains molybdenum.
As of January 2010, proven reserves at Antamina stand at 100Mt graded at 1.14% copper, 0.17% zinc, 8.7g/t silver and 0.036% molybdenum. Proven reserves of copper-zinc ore are 42Mt graded at 0.99% Cu, 2.30% Zn, 19.5g/t Ag and 0.009% Mo.
Probable Reserves of copper ore are 454mt at 1.05% copper, 0.17% zinc, 9.7g/t silver and 0.031% Molybdenum. Probable Reserves of Zinc ore as of January 2010 stand at 149mt graded at 1.05% Cu, 2.07% Zn, 17.9g/t Ag and 0.008% Mo.
Measured, indicated and inferred resources during the same time stood at 130Mt, 581Mt and 489Mt, respectively.