Trump Cut a Billion-Dollar Mining Deal. His Sons Stand to Profit.

When Commerce Secretary Howard Lutnick met with Kazakhstan's president at the St. Regis Hotel last September in New York, President Trump jumped in by phone as the men sealed a deal on a top priority for Washington.

During the call, Mr. Trump and his team won an agreement from the Kazakh leader to give a little-known American company access to one of the world's largest untapped reserves of tungsten, a metal that the United States desperately needs for the production of missile warheads, fighter jets, computer chips and other critical goods.