By Agence France-Presse
Theunissen, South Africa
The Sibanye-Stillwater mining company said a massive power outage caused by a storm had prevented lifts from bringing the night shift to the surface at the Beatrix gold mine, in the small town of Theunissen near the city of Welkom.
"We have got 955 employees still underground, they are in a confined and safe area, it's the shaft waiting area (and) there is ventilation, we are supplying them with water and food," James Wellsted, spokesman for Sibanye-Stillwater, told AFP.
"So everybody is fine at the moment. We are trying to restore power so we can start hoisting them to the surface," he said, speaking on the phone from the mine.
He said the depth where the miners were trapped was uncertain, but the mine has 23 levels, going down to about 1,000 metres (3280 feet) below ground.
One cable was restored during the day and 272 workers were rescued, but 955 remained trapped by early evening, the company said.
They have been underground for over 24 hours and nervous family members patiently gathered along the road to the shaft, kept a distance by security guards. A generator at the shaft had started working.
"The last time I heard from him was at 9:00 pm (1900 GMT on Wednesday). We believe nobody is hurt. But it is becoming long. The generator is not strong enough to pull the cage. God I hope he is going to come out tonight." a woman, whose husband was among those trapped, told AFP smoking a cigarette while sitting in her car. She refused to give her name.
Another woman waiting for her husband, who only gave her first name as Innocentia, said: "we are pretty optimistic. They say they are safe".
Earlier Wellsted had said that engineers were struggling with a software fault to get emergency generators to operate and re-start the lifts following the storm.
"We are having some issues -- probably related to the power surge linked to the storm -- in getting the winders working, so we are busy working on that issue at the moment," he added.
"Last night there was a severe storm in the Free State (province) that affected two different power cables... and cut off all electricity supply to the mine, so we were unable to bring the night shift up."
The rescue efforts would continue throughout the night, he said
The Beatrix mine is in Free State province, 290 kilometres (180 miles) southwest of Johannesburg.
AMCU, the Association of Mineworkers and Construction Union, said that the workers stuck underground were facing major health and safety risks.
"AMCU views this incident as extreme due to the sheer number of workers involved," it said in a statement.
"The incident raises serious concern regarding the lacking emergency contingency plans at the mine for alternative and back-up power generation."
Another mining union the National Union of Mineworkers (NUM) complained about mine safety and called on mineworkers to refuse to work in "dangerous conditions".
"Major multinational corporations like Sibanye-Stillwater which should be industry leaders in creating a safety culture are doing far too little to prevent accidents," the union said in a statement.
A parliamentary committee on mining expressed outrage at the accident, calling for "drastic" action to be taken against the mining company and saying it was "utterly unacceptable" that the mine had no backup plan to bring the workers to the surface.
An ANC member, Siyabonga Sikade, whose uncle was also among those trapped asked:"Why are our people still trapped when (mine owners) are making so much money? What is their plan in case of a catastrophe?"
Last August five mineworkers died after sections of a gold mine collapsed outside Johannesburg.
The country possesses rich mineral reserves and has some of the world's deepest gold mines.
Gold was for many decades the backbone of South Africa's economy, but production has declined sharply due to depletion of reserves.