The accident occurred on Thursday in the Kolwezi area of Lualaba province when two galleries caved in at the KOV open-pit mine operated by the Kamoto Copper Company (KCC), a subsidiary of Glencore.
Glencore said in a statement: "The illegal artisanal miners were working two galleries in benches overlooking the extraction area. Two of these galleries caved in."
Artisanal mining by independent workers using their own materials on the edge of commercial mine sites is a big problem across Africa.
The statement said KCC had observed a "growing presence" of illegal miners, with an average of 2,000 people daily sneaking onto its operating sites.
The rudimentary and often outdated practices employed by independent miners can compromise the safety of the mines, and accidents among them are common.
"KCC urges all illegal miners to cease from putting their lives at risk by trespassing on a major industrial site," Glencore said.
