KASULO, Democratic Republic of Congo — A man in a pinstripe suit with a red pocket square walked around the edge of a giant pit one April afternoon where hundreds of workers often toil in flip-flops, burrowing deep into the ground with shovels and pickaxes.
His polished leather shoes crunched on dust the miners had spilled from nylon bags stuffed with cobalt-laden rocks.
The man, Albert Yuma Mulimbi, is a longtime power broker in the Democratic Republic of Congo and chairman of a government agency that works with international mining companies to tap the nation’s copper and cobalt reserves, used in the fight against global warming.
Mr. Yuma’s professed goal is to turn Congo into a reliable supplier of cobalt, a critical metal in electric vehicles, and shed its anything-goes reputation for tolerating an underworld where children are put to work and unskilled and ill-equipped diggers of all ages get injured or killed.
“We have to reorganize the country and take control of the mining sector,” said Mr. Yuma, who had pulled up to the Kasulo site in a fleet of SUVs carrying a high-level delegation to observe the challenges there.
But to many in Congo and the United States, Mr. Yuma himself is a problem. As chairman of Gécamines, Congo’s state-owned mining enterprise, he has been accused of helping to divert billions of dollars in revenues, according to confidential State Department legal filings reviewed by The New York Times and interviews with a dozen current and former officials in both countries.
Top State Department officials have tried to force him out of the mining agency and pushed for him to be put on a sanctions list, arguing he has for years abused his position to enrich friends, family members and political allies.