Alternative production and recycling solves – their cards don’t assume new facilities

In the event of a longer Chinese supply interruption, the U.S. rare earths mine at Mountain Pass, Calif., would likely become the first place to step up production, Gholz explains. The mine's previous owner, Molycorp, spent approximately $1.5 billion building a new separation facility for producing rare earth concentrates. It did not, however, complete the downstream processing needed to produce purified rare earth materials before the company went bankrupt in 2015 because of Chinese competition. The mine's new owner, MP Materials, plans to reactivate and complete the mothballed facility for fresh operation starting in 2020.

Another alternative is Australian company Lynas Corp., the world's only significant rare earths producer outside China. It currently operates a mine at Mount Weld in Australia, and sends ores to a separation facility in Malaysia that can purify the rare earth materials—but a complication has arisen from the fact that some ores contain radioactive thorium. Environmental concerns about low-level radioactive waste from the separation facility recently led Lynas to announce it will move some some of the "upstream" processing (which involves the radioactivity) back to Australia, while keeping "downstream" processing in Malaysia. The company has also announced it will work with Texas-based Blue Line Corp. to build a new separation facility in the U.S. for operations starting in 2022 at the earliest.

Beyond existing mines, companies that dig for other resources might start extracting rare earth elements from deposits of different materials. For example, the U.S. could someday obtain these elements as byproducts from power plant coal ash and coal mining waste. And radioactive material mixed in with ores could end up being positive: If thorium-based nuclear plants prove viable, expanded thorium mining would also turn up usable rare earth minerals. Researchers have even begun investigating a large concentration of rare earth elements in deep-sea mud from an ocean floor deposit near Japan.