Rio Tinto will spend US$10 million to build a pilot plant to extract lithium from waste rock, or tailings, at its borates business in California using a heat-and-leaching process, Reuters reported Oct. 21, citing a company executive.
The pilot plant will produce about 10 tonnes per year. If the pilot phase is successful, the mining giant will consider spending US$50 million to build an industrial plant with lithium production capacity of 5,000 tonnes per year, which may be brought into commercial production.
Rio Tinto said it discovered lithium at a higher concentration than at competing U.S. projects under development while examining the tailings for gold, without providing an exact percentage.
The company's chief executive of energy and minerals, Bold Baatar, said the plant will be a "low-energy option" for lithium production as the source material was already mined.
Rio Tinto said the facility has potential to become the largest lithium producer in the U.S. but did not provide any long-term output targets.
The move comes as the U.S. government pushes domestic miners to expand the production of strategic minerals for electric vehicle batteries and other high-tech equipment amid the ongoing trade war, to cut the country's reliance on China.