Chile’s Atacama salt flat is sinking at a rate of 1 to 2 centimeters (cm) per year due to the extraction of lithium-rich brine, according to a study by the University of Chile.
The study used satellite data collected between 2020 and 2023 to check deformations in the Earth’s crust. It was published in the journal IEEE Transactions on Geoscience and Remote Sensing.
Francisco Delgado, a researcher at the University of Chile’s Department of Geology and lead author of the report, said the sinking area is in the southwestern part of the salt flat, where lithium miners operate.
“It’s not the entire salar,” Delgado said, adding that the area coincides with parts where “companies are doing most of their pumping or the most intense pumping.”
In his report, Delgado said the pumping of lithium-rich brine occurs at a faster rate than aquifer recharge, leading to subsidence, or the downward vertical movement of the Earth’s surface.
“Subsidence due to irreversible changes in permeability can be a very serious problem,” Delgado said, adding that the area measures approximately 8 kilometers from north to south and 5 kilometers from east to west.
The data were obtained by the SAOCOM-1 satellite constellation of the National Commission for Space Studies of Argentina, using a synthetic aperture interferometric radar.
Chile, the world’s second largest lithium producer, extracts the light metal from the Atacama salt flat, which has one of the largest lithium reserves in the world.
The metal, essential in electric vehicles, batteries and the energy transition, is obtained through evaporation, in which 90% of the water is lost to the atmosphere.
Native communities surrounding the Atacama fear that mining could be depleting scarce freshwater and lithium-rich brine, reducing its availability to people and wildlife.
Environmental authorities have accused SQM and Albemarle, the two lithium producers in Chile, of possible irregularities regarding brine extraction. They intend to switch to Direct Lithium Extraction (DLE).
Extraction promises to be more sustainable by reinjecting groundwater after lithium extraction, but the technology is still in the testing phase.
Chile’s SQM recently partnered with state-owned copper giant Codelco as the country looks to expand its lithium production.
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