The number of people killed by a gas explosion at Gloria coal mine in Middelburg, Mpumalanga, has risen to six, and more than 20 others remain trapped, an official at the mine said on Thursday.
The representative of the creditor protection team at the mine, Michael Elliot, said more people still stuck underground in the unused mine are presumed dead.
"As I've been informed, there are six deceased people in this point in time that have been taken to the mortuary," Elliot told Reuters over the phone.
Rescue efforts were hampered by dangerously high levels of toxic gas underground, Elliot said.
"We first have to restore power to the mine and we have to restore the ventilation to make it safe and once it's safe ... then we will go and recover these people that are missing," he said.