Cleveland-Cliffs is looking into building a rare earths mining business, CEO Lourenco Goncalves told investors Monday.

The steelmaker has two sites in Michigan and Minnesota where geological surveys have found indications of rare earths, Goncalves said in a statement on Cleveland-Cliffs’ third-quarter earnings.

“We are working with the geologists to assess whether these deposits could become commercially viable — that’s where we are at,” Goncalves told analysts on the company’s earnings call later Monday morning. “We are a mining company, this isn’t new territory for us.”

Shares of Cleveland-Cliffs closed more than 20% higher at $16.18. The Cleveland headquartered steelmaker is experienced in mining iron ore.

Rare earths are used to manufacture magnets that are key inputs in U.S. weapons platforms, electric vehicles, semiconductor fabrication, robotics and other applications.

China dominates the global rare earths supply chain and the U.S. is dependent on Beijing for imports. China announced strict export controls on rare earths earlier this month, provoking President Donald Trump to threaten 100% tariffs in retaliation.

The U.S. has only one commercial rare earths mine. The Defense Department struck a deal in July with the mine’s owner, MP Materials, that included an equity stake, a price floor and an offtake agreement.

Investors have been speculating that the Trump administration will strike similar deals with other U.S. companies that are trying to stand up domestic rare earths mines and processing facilities.

Cleveland-Cliffs’ sites in Michigan and Minnesota, if successful, would align the company with the administration’s “broader national strategy for critical mineral independence,” Goncalves said.

“American manufacturing shouldn’t rely on China or any foreign nation for essential minerals, and Cliffs intends to be part of the solution,” the CEO said.