‘Diamond Joe’ Gutnick’s Son Exits Miner With $350 Million Stake

The son of an Australian mining entrepreneur sanctioned by the country’s securities regulator has left the board of USA Rare Earth Inc. with a stake worth more than $350 million.

Mordechai Gutnick, 48, stepped down last week after previously announcing he wouldn’t run for reelection. USA Rare Earth said the decision was related to its acquisition of a Brazilian mining firm that will add two new directors to the board.

“USA Rare Earth’s board is focused on one mission: Building a fully integrated rare earth and permanent magnet value chain outside of China,” a spokesperson said in an emailed ...