The potential shift back to producing rare earths shows how these mining projects evolve over time in response to the market, said professor Rod Eggert, deputy director of the Critical Materials Institute at the Colorado School of Mines.

“We have to be more forward thinking,” said Alexander Gysi, an assistant professor in geology and geological engineering at the Colorado School of Mines in Golden. “It would be better for the U.S. to have a greater range of sources for rare earths.”