The workers were safe and gathered at an assembly point in the underground gold mine, one of the company’s deepest, located around 60km west of Johannesburg, it said.

It did not provide details on the incident, though a Sibanye spokesperson confirmed it had occurred in the mine’s Kloof 7 shaft, adding that all the miners were accounted for and the company was providing them with food.

Safety procedures and an examination of the shaft were under way, the spokesperson added, after which the miners would be hoisted to the surface.

“We expect the situation to be resolved by about midday today,” the spokesperson said.

Mining accidents are not uncommon in South Africa, which has some of the world’s deepest and oldest gold mines.

Earlier this year, at least 78 bodies were pulled from an illegal gold mine after police cut off food and water supplies for months in an attempt to crack down on illegal mining activity.

Johannesburg-based Sibanye is among only a few South African miners squeezing profits from the area’s gold deposits. The precious metals producer is mining at depths of about 3,200m at the Kloof 7 shaft.

The Kloof mine, which accounts for 14% of Sibanye’s total gold output, also operates two other shafts.

The National Union of Mineworkers (NUM) earlier said it had received reports of the incident, which it said happened at around 10pm (0800 pm GMT) on Thursday.