Coal producer, Exxaro, said Eskom had lifted the force majeure it declared during the hard lockdown as power supplier recorded a dip in energy demand.
The clause which which frees the contracting party from liability in the event of an extraordinary circumstances that may prevent the execution of a contract was invoked by Eskom on in mid-April, and Exxaro had argued at the time that it believed the process was not warranted and vowed to challenge it.
The notice was said to only affect the supply of coal to the Medupi and Matimba power stations.
The JSE-listed company said in a statement on Friday it was still of the view that the event "did not constitute a force majeure, as the power stations have been capable of supplying power."
Financial earnings for the first quarter of 2020 stated that its revenue was boosted by coal exports and higher volumes to Eskom.
Eskom had also issued notices that it would halt supply from independent power producers for limited hours of day due to slow demand, in what was met with threats of legal action by the industry.
The state-owned power utility currently has system breakdowns at some of its power stations leading to rolling outages across the country.