Escondida is a copper mine at elevation in the

Atacama Desert The Atacama Desert ( es, Desierto de Atacama) is a desert plateau in South America covering a 1,600 km (990 mi) strip of land on the Pacific coast, west of the Andes Mountains. The Atacama Desert is the driest nonpolar desert in th ...

Antofagasta Region The Antofagasta Region ( es, Región de Antofagasta, ) is one of Chile's sixteen first-order administrative divisions. The second-largest region of Chile in area, it comprises three provinces, Antofagasta, El Loa and Tocopilla. It is bordered t ...

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the eas ...

Geology

The Escondida deposit is one of a cluster of porphyry coppers in an elongated area about 18 km north–south and 3 km east–west and is associated with the 600 km long West Fissure (''Falla Oeste'') system, which is in turn associated with most of the major Chilean porphyry deposits. A barren, leached cap, in places up to 300 metres thick, overlies a thick zone of high grade secondary

supergene A supergene is a chromosomal region encompassing multiple neighboring genes that are inherited together because of close genetic linkage, i.e. much less recombination than would normally be expected. This mode of inheritance can be due to genom ...

mineralisation of the main orebody, largely

chalcocite Chalcocite (), copper(I) sulfide (Cu2S), is an important copper ore mineral. It is opaque and dark gray to black, with a metallic luster. It has a hardness of 2.5–3 on the Mohs scale. It is a sulfide with a monoclinic crystal system. ...

and covellite, which in turn overlies the unaltered primary mineralisation of

chalcopyrite Chalcopyrite ( ) is a copper iron sulfide mineral and the most abundant copper ore mineral. It has the chemical formula CuFeS2 and crystallizes in the tetragonal system. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mo ...

bornite Bornite, also known as peacock ore, is a sulfide mineral with chemical composition Cu5 Fe S4 that crystallizes in the orthorhombic system (pseudo-cubic). Appearance Bornite has a brown to copper-red color on fresh surfaces that tarnishes to v ...

and

pyrite The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Iron, FeSulfur, S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic Luster (mineralogy), lust ...

Reserves

At mid 2007, Escondida had total proven and probable reserves of 34.7 million tonnes of copper, of which 22.5 million tonnes is estimated to be recoverable. Total

resources Resource refers to all the materials available in our environment which are technologically accessible, economically feasible and culturally sustainable and help us to satisfy our needs and wants. Resources can broadly be classified upon their av ...

(including reserves) were 57.6 million tonnes of copper, of which 33.0 million tonnes should be recovered. Exploration continues. As of 2019, the known resource is 21.7 Billion tonnes at 0.54 percent Copper including Escondida and adjacent deposits. The mine and ancillary industries contributes 2.5% to Chile’s GDP.

Operation

Sulfide ore, which contributes 77% of the recoverable copper reserve, is crushed and milled in one of the two concentrators and the copper concentrate is separated out using

froth flotation Froth flotation is a process for selectively separating hydrophobic materials from hydrophilic. This is used in mineral processing, paper recycling and waste-water treatment industries. Historically this was first used in the mining industry, wher ...

. Approximately 86% of the copper is recovered. It is piped down to the port of Coloso, where it is dewatered before shipping. Oxide ore, 4% of recoverable copper, is crushed, agglomerated and then acid leached in large heaps, and the copper is recovered from the leach solutions as copper cathode in a solvent extraction/electrowinning (SX/EW) plant. Recovery is 68%. The low grade sulfide ore contributes 19% of recoverable copper. It is also crushed and dumped on large heaps, but here the leaching occurs through oxidation induced by

microorganisms A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...

. The copper is also recovered by SX/EW. In 2006, 338.6 million tonnes were mined (928,000 tonnes per day), of which 251.5 million tonnes were waste and oxide ore. Sulphide ore totalled 87.1 million tonnes or 239,000 tonnes per day. The two camps, San Lorenzo and 2000, cater to 7,000 people daily. Esconidida's current capacity is around 1.4 million tonnes of copper production per year, making it the largest copper mine in the world. In 2005, Degrémont Industry was asked to install a new Sea Water Reverse Osmosis plant with capacity to produce 12 Million gallons of fresh water per day. Construction of work force accommodation camps and field offices are needed services in order to have the mine operating, on this note Tecno Fast in 2012 was hired to build the second phase of the respective workforce accommodation camp for Escondida Mine. BHP buys 3 TWh of electricity per year to operate the Escondida and Spence mines (1.640 m elevation), where solar energy is more than 3.000 kWh/m² per year.

References

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External links

Great Deposits of the World – La Escondida Porphyry Copper, Chile
updated October 17, 2019 Atacama Desert Copper mines in Chile Mines in Antofagasta Region Open-pit mines Surface mines in Chile

Geology

Reserves

Operation

See also

References

External links