At least 36 people have been killed after a copper and cobalt mine collapsed in Lualaba province in south-east DR Congo, authorities say.
The provincial governor Richard Muyej blamed the accident on what he called "clandestine artisanal diggers".
Unofficial mining is common in the region and people do it as a means to make a living.
Mines in southern DR Congo produce more than half of the world's cobalt - a key component in mobile phone batteries.
Prices for it more than doubled last year thanks to increased demand for electric cars, which also use the mineral in their batteries.
The accident happened on Thursday at the Kamoto Copper Company, a subsidiary of Swiss mining giant Glencore, based near Lualaba's main city of Kolwezi.
More bodies could be found as rescue work continues at the mine, the BBC's Gaius Kowene reports from the capital, Kinshasa.
Unofficial, or clandestine, mining is common in mineral rich areas but efforts by security services to try and stop it are often fruitless, our reporter says.
Glencore said in a statement that 19 people had been killed but added that there were possible unconfirmed fatalities.
It added that its mines have been targeted by illegal miners:
"This has led to daily intrusions onto its concession by on average 2,000 illegal artisanal miners per day. This has presented a significant risk to its employees, operating equipment and the illegal artisanal miners themselves".
Lualaba's governor Richard Muyej also blamed illegal miners for the accident:
"Clandestine artisanal diggers who have flooded [the mine] and engaged in an anarchic exploitation," he said, news agency Reuters reported.
Reserves of cobalt and other minerals like diamonds, copper and gold, should make DR Congo one of the richest countries in Africa, but its people are among the poorest.
DR Congo has been exploited for its wealth since the first European explorers arrived in the 15th Century.