In spring 1949, three prospectors armed with Geiger counters set out to hunt for treasure in the arid mountains of southern Nevada and southeastern California.
But that wasn’t the end of the story. The green-tech revolution of the 21st century brought new attention to Mountain Pass, which later reopened and remains the only U.S. mine for rare earths. But there are ways to reduce mining’s footprint, says Thomas Lograsso, a metallurgist at the Ames National Laboratory in Iowa and the director of the, a Department of Energy research center. Researchers are investigating everything from reducing the amount of waste produced during the ore processing to improving the efficiency of rare earth element separation, which can also cut down on the amount of toxic waste.
The pipeline repeatedly ruptured over the years. At least 60 separate spills dumped an estimated 2,000 metric tons of wastewater containing radioactive thorium into the valley. Federal officials feared that local residents and visitors to the nearby Mojave National Preserve might be at risk of exposure to that thorium, which could lead to increased risk of lung, pancreatic and other cancers.
In 2010, officials in the nearby city of Baotou noted that radioactive, arsenic- and fluorine-containing mine waste, or tailings, was being dumped on farmland and into local water supplies, as well as into the nearby Yellow River. The air was polluted by fumes and toxic dust that reduced visibility. Residents complained of nausea, dizziness, migraines and arthritis.
Unfortunately, Molycorp “was an epic debacle” from a business perspective, says Matt Sloustcher, senior vice president of communications and policy at, current owner of Mountain Pass mine. Mismanagement ultimately led Molycorp to file for Chapter 11 bankruptcy in 2015. MP Materials bought the mine in 2017 and resumed mining later that year. By 2022, Mountain Pass mine was producing 15 percent of the world’s rare earths.
Like stage 2, stage 3 is already under way. In 2022, the company broke ground in Fort Worth, Texas, for a facility to produce neodymium magnets. And it inked a deal with General Motors to supply those magnets for electric vehicle motors.The process is difficult and leads to lots of waste. Rare earth elements are extremely similar chemically, which means they tend to stick together.