The mining company said in a statement that the state power utility Eskom told them to reduce their electricity use to essential use in their three mines.
South Africa has announced substantial power cuts nationwide.
Some 6000 Megawatts of electricity – roughly 10 per cent of the grid – is being switched off.
Officials are blaming heavy rain for problems at coal power stations.
But the BBC’s Andrew Harding reports that President Cyril Ramaphosa acknowledged that Eskom was in crisis because of years of corruption and mismanagement.
Mr Ramaphosa insisted his government was taking the necessary steps to fix Eskom, and other state companies like the national airline, which is now teetering on the brink of bankruptcy.
