ArcelorMittal South Africa said on Tuesday it had cut its power usage due to power supply shortages by utility Eskom but that its plant was still operating.
Eskom has an agreement with major power users, such as ArcelorMittal, requiring them to reduce electricity consumption by 10 percent when supply is constrained.
(READ MORE: South Africa's Eskom cuts power for 4th straight day)
"We have been affected the whole of today. There are agreed levels and we turn down within those levels," said Kesebone Maema, a spokeswoman for the unit of the world's biggest steelmaker.