Chile’s thirsty copper mines to increase seawater use

There is a glimmer of hope in a new report that predicts an increase in water use by Chile’s huge copper industry: most of it will come from the sea rather than reducing inland supplies.

While the mines at the largest copper producer are looking for ways to use less water, there is not much they can do.

Much of the expected 21% increase in production by 2032 will come from low-grade sulphide deposits that need more water to process, according to the report released Wednesday by copper agency Cochilco. That will raise the use of the vital mining liquid to 20.9 cubic meters (about half of an average domestic swimming pool) per second.

The mines are increasingly thirsty just as a decade-long drought and booming agricultural exports put Chile’s depleted freshwater reserves under pressure.

Requirements to safeguard supplies for human consumption under a new Constitution currently being drafted are on the rise.

The Cochilco report estimates that the use of seawater in mining, whether used directly or desalinated, will increase by 167% by 2032, while the use of fresh water will decrease by 45%. At the end of that period, 68% of the water used by the industry will come from the ocean, the agency concluded.

It remains to be seen if that is enough to appease water activists and the general population.