Workers were back on the job on Thursday at South African power utility Eskom's Medupi plant after a brief stoppage earlier in the day, a spokeswoman for the state-run company said.
An official at the National Union of Metalworkers of South Africa earlier said workers at Medupi had marched to protest plans by a sub-contractor to dismiss up to 1 200 union members.
Getting power from the plant by the end of the year is key to relieving razor-thin margins in Africa's top economy.