Some 1,800 people are trapped underground in Sibani's gold operation after a shaft incident, the company said.
The company may use a nearby shaft to hoist the workers
Surface, although there is currently no estimate when it can
It happened, a spokesman said.
A few underground tracks fell on the shaft and blocked it, said James Wallstead, a spokesman.
Sibanye assesses the shaft infrastructure, which may take several hours, he said.
There were no casualties as a result of the accident.
The workers entered the mine this morning and the incident took place around lunch, around the time they usually finished their shift, he said.
The event may revive concerns about safety at Sibani, who last year experienced spike in fatal accidents.
About 1 000 workers were also trapped underground for more than one day on one of its gold mine in February 2018 after a power outage.
Sibanye fell as much as 4.1% and traded 2.7% lower at 16:31 in Johannesburg.
* This story will be updated when and when the information becomes available