Escondida
| Company type | Mining |
|---|---|
| Industry | Copper mining |
| Headquarters | Chile |
| Products | Copper, gold |
Number of employees | 7000 |
| Parent | BHP |
Escondida is a significant open-pit copper extraction site situated at an elevation within the Atacama Desert of the Antofagasta Region, Chile. Recognized as one of the globe’s most prolific copper producers for many years, it also ranks first in Chile for both copper and gold output. In 2019, the mine along with its associated industries accounted for roughly 2.5% of Chile’s overall GDP. The majority of its production is exported to China in the form of ore concentrate, which in 2020 was estimated to contain about 4% chalcopyrite, 35% chalcocite, and 46% pyrite.
Geology
The Escondida ore body belongs to a group of porphyry copper deposits spanning an area approximately 18 km from north to south and 3 km from east to west. It is linked to the extensive West Fissure (Falla Oeste) fault system, which extends 600 km and is associated with many prominent porphyry deposits throughout Chile. A leached, barren cap reaching up to 300 meters thick covers a zone of high-grade secondary supergene mineralization largely composed of chalcocite and covellite. Beneath this lies the primary mineralization containing chalcopyrite, bornite, and pyrite.
Reserves
As of mid-2007, Escondida’s proven and probable copper reserves were estimated at 34.7 million tonnes, with 22.5 million tonnes considered recoverable. The total resource base, including reserves, was reported at 57.6 million tonnes of copper, with an anticipated recovery of 33.0 million tonnes. Exploration activities continue actively. By 2019, the combined known resource across Escondida and neighboring deposits totaled approximately 21.7 billion tonnes grading 0.54% copper. The mine and its related sectors contribute around 2.5% to Chile’s GDP.
Operation
Sulfide ores, which make up 77% of recoverable copper reserves, undergo crushing and milling in two concentrators where froth flotation is employed to separate copper concentrate with about an 86% recovery rate. This concentrate is then transported via pipeline to the port of Coloso for dewatering before export. Oxide ore, accounting for roughly 4% of recoverable copper, is processed through crushing, agglomeration, and acid heap leaching; copper recovery is achieved by solvent extraction/electrowinning (SX/EW) with a recovery efficiency near 68%. Low-grade sulfide ore contributes about 19% of recoverable copper and is treated by bioleaching on heaps followed by SX/EW recovery.
In the year 2006, Escondida extracted a total of 338.6 million tonnes (averaging 928,000 tonnes daily), including 251.5 million tonnes consisting of waste and oxide ore and 87.1 million tonnes of sulfide ore (approximately 239,000 tonnes daily). The two workforce camps accommodate around 7,000 employees each day. Maintaining an annual output capacity close to 1.4 million tonnes of copper production, Escondida continues to hold the title as the largest copper mine worldwide.
To facilitate ongoing operations, workforce housing camps and field offices are critical; in 2012, Tecno Fast was awarded the contract to construct the second phase of accommodation facilities.
BHP annually acquires about 3 TWh of electricity to power both Escondida and the nearby Spence mine—both situated at high altitudes (~1,640 m)—where solar radiation potential exceeds 3,000 kWh/m² per year.
Water usage
Between 1998 and 2019, Escondida obtained its freshwater supply from a well field located within the Monturaqui sector of the Monturaqui-Negrillar-Tilopozo Aquifer, situated 78 kilometers east of the mining site, with a withdrawal capacity of 1,400 liters per second. In 2022, Escondida, together with Albemarle and the adjacent Zaldívar copper operation, was subject to legal proceedings concerning excessive groundwater extraction that allegedly harmed the environment and impacted the indigenous Atacameño community. Escondida maintained that any downstream consequences had not yet occurred due to the slow movement of groundwater and contended that the primary effects were caused by the other companies involved. In 2024, the First Environmental Court of Antofagasta mandated Escondida to pay compensation exceeding US$8 million in relation to this matter.
In 2005, Degrémont Industry established a Sea Water Reverse Osmosis desalination facility capable of producing 45 million liters daily. By 2024, Escondida's freshwater requirements have been entirely met by this desalination plant located near Caleta Coloso on the coastline.
See also
External links
- Great Deposits of the World – La Escondida Porphyry Copper, Chile, updated October 17, 2019