About 2000 workers affiliated to Numsa at Glencore in Emalahleni Mpumalanga have downed tools.
More than 15 bus companies have indicated that they will go on a nationwide strike on Wednesday, forcing thousands of commuters to seek alternative transport.
The National Union of Metalworkers of South Africa (Numsa) says they are thrilled as they, along with the Transform RSA, stopped Eskom from signing 27 contracts with Independent Power Producers (IPP).
Numsa says the High Court in Pretoria granted the interdict preventing Energy Minister Jeff Radebe from signing a deal with 27 renewable energy producers late on Monday night.
Numsa on Tuesday marched to the Zambian High Commission in Pretoria, demanding urgent steps to foster democracy in Lusaka and respect for human rights and press freedom.