Piles of crushed ore sit at the Mountain Pass mine, operated by MP Materials, in Mountain Pass, California, U.S., on Friday, June 7, 2019. America's only rare earths producer, MP Materials, has been shipping all its output from the Mountain Pass mine in California to China because there is currently no refining capacity available to handle its production anywhere else in the world, its biggest shareholder said last month.

Mining Rare Earths for a Renewable Future