Arkansas may have huge lithium reserves, researchers say

Researchers from the United States Geological Survey and the Arkansas government announced Monday that they have found lithium, an important raw material for electric vehicle batteries, in an underground brine reservoir in Arkansas.

Using water testing and machine learning, the researchers determined that a geologic region known as the Smackover Formation could contain between 5 million and 19 million tons of lithium—enough to meet all of Earth's demand for the metal. Several companies, including Exxon Mobil, are developing projects in Arkansas to produce lithium, which is dissolved in underground brine.

Whether lithium will be harvested in the region will depend on the ability of those companies to scale new methods of extracting the valuable battery material from saltwater. The processing technique that Exxon and others are pursuing in Arkansas, known as direct lithium extraction, typically costs more than conventional methods, according to consulting firm Wood McKenzie.

Energy and mining companies have long produced oil, gas and other natural resources in a smackover that stretches from Texas to Florida. And federal and state researchers say lithium can be extracted from the brine waste stream from which companies extract other forms of energy and materials.

The energy industry, encouraged by the Biden administration, is increasingly working to produce the raw materials needed for lithium-ion batteries in the United States. A few projects have started recently, and many more are in various stages of study and development across the country.

Most of the world's lithium is produced in Australia and South America. Much of it is processed in China, which also dominates the manufacture of electric vehicle batteries.

“The potential for increased U.S. manufacturing to replace imports has implications for employment, manufacturing and supply chain resilience,” U.S. Geological Survey Director David Applegate said in a statement announcing the study. “This study illustrates the value of science in addressing economically important issues.”

Federal researchers have also identified other potential resources that could produce large amounts of lithium, including the Salton Sea in southern California, where Berkshire Hathaway Energy and other companies are working to extract lithium from hot fluids pumped from aquifers 4,000 feet below. Ground by geothermal power plants.

Exxon Mobil recently drilled exploratory wells in Arkansas and is evaluating whether it can extract lithium in a cost-competitive way, Dan Ammann, president of the company's Low Carbon Solutions business, said in an interview last month.

“We know we have an attractive asset. We are working to understand that cost equation, working to understand the demand and supply picture,” Mr. Amman said at the time.

Exxon said last year that it aims to enter production in 2027 and produce enough lithium to supply more than one million electric cars per year by 2030.

Chile, one of the world's leading producers of the metal, has already extracted lithium from brine. Companies that operate there typically hold brine in large ponds until the liquid evaporates, leaving various minerals behind. This process is relatively inexpensive, but it takes time and can affect freshwater supplies.

Several companies hope that direct lithium extraction will allow them to more efficiently remove lithium from brine with filters and other equipment. Such a method would use less land and may have a smaller environmental impact than evaporation ponds. But it could take years for mining and energy companies to perfect the technology and deploy it on a large scale.