Giant Chile Copper Mine Charged With Water Misuse

5 Aug 2020 by Staff - Water Diplomat

Mining giant BHP Billiton, operator of the world’s largest copper mine, Escondida, in Chile was charged 31 July with exceeding water extraction thresholds over the past 15 years.

“The company, despite committing to reduce its extraction of water … exceeded the maximum level permitted since 2005, tripling that level in 2019,” Chile’s regulator said in a statement.

The infraction has been serious enough to have caused a 25 centimeter decrease in the water table level in the Atacama desert, the world’s driest. The decrease is the “allowable” limit but could lead to closure of the mine, revocation of its environmental assessment, or impostion of fines. The operator has 10 business days to produce a compliance program.

Earlier in July, a top environmental court called for a government-vetted water study in order to address lingering questions about mining sustainability in Chile’s north.

The area has become drier over the last decade adding an extra layer of difficulty for mining companies: for water is expected to soar as ore grades decline.

According to OOSKAnews, on 4 February the mine announced that it has reconsidered plans to continue water extractions from the vulnerable Atacama salt flats in Chile, and advance deployment of desalination technology.

While rich in copper and lithium deposits, Chile’s Atacama region presents severe operating challenges for extraction companies. In 2019 copper production in Chile dropped by 44,000 tons compared to 2018, attributable to water scarcity, falling ore grades at many deposits, and aging infrastructure. Escondida’s 2019 production was down more 4 percent over 2018.

BHP Billiton, with a 57 percent interest in the mine, has said that it will switch entirely to using desalinated water by 2030. Already fulfilling 40 percent of the mine’s water requirements, desalinated water comes from a recently completed $3.4 Billion USD coastal desal plant and is transported 3200 meters above sea level.

A statement from BHP said that the “decision advances by 10 years (BHP’s) commitment to stop extracting high Andean water for Escondida.” It had previously said it would shut off the freshwater taps in 2030. The statement also indicated that the decision had considered conversations with indigenous communities in the region.

Data from the national mining association estimates that about 20 percent of the water currently used by major copper miners comes from the sea and it is expected that by 2029 about 40 percent will be desal.