Earlier this year, the world's two biggest lithium producers publicly celebrated new deals with Chile's government that will allow them to vastly increase the output of the ultralight battery metal from the Atacama, the world's driest desert.
U.S.-based Albemarle Corp and Chile's SQM operate just 3 miles (5 km) apart in the remote Salar, a basin in the Atacama that is home to one of the world's richest deposits of high-grade lithium. Lithium-ion batteries are key components for most consumer electronics, from cell phones and laptops to electric cars.
In celebrating the new contracts, the two companies said they were confident they could significantly boost output without drawing more than their current quotas of lithium-rich brine, or saltwater, that has for millennia accumulated in pools beneath the Atacama. The rivals said each had all the brine they needed for current and future production.
But a Reuters review of filings with Chile's environmental regulator shows Albemarle striking a different tone.
In the filings, which have not been previously reported, Albemarle voices concern about a 2016 investigation by Chilean authorities that found over a period of several years SQM sucked up more of the lithium-rich brine from beneath the Salar than its permits allowed.
Hydro-geologists and environmental chemists consulted by Reuters on the filings said the back-and-forth between the miners underscores widespread concerns over just how much brine is left and how long it will last. They said the filings show that neither the Chilean authorities nor the companies have a clear picture of the water situation at a time when the miners have been given the green light to boost production.
The true state of the Salar's water supply, both fresh and saltwater, has become an obsession of lithium industry watchers because of the area's huge importance in satisfying soaring global demand for the powdery white metal. The area is the most cost-efficient place in the world to mine the metal, and both SQM and Albemarle have staked much of their future production on the Salar.
But for some experts and local Indigenous communities that surround the Atacama salt flat, questions over the mining operations still outweigh answers.