The National Union of Mineworkers (NUM) says it is consulting with its lawyers to determine the next course of action for its members at Optimum Coal Mine, which has been placed into business rescue.

The 2,500 workers have embarked on an indefinite strike following the Gupta-owned mine’s failure to pay salaries.

The NUM said the mine's management had not been forthcoming with information about its financial difficulties, leaving members anxious and confused.

Operations at the Gupta owned Koornfontein mine in Mpumalanga have also been halted as workers refuse to continue with work until they are paid.

“Workers were caught off guard, they did not know about the business rescue. They are also waiting to meet the company CEO as they are anxious about the future of the company,” NUM spokesperson Livhuwani Mammburu said.

On Thursday Eskom announced that it had stopped settling invoices submitted by Optimum since the beginning of February due to failures to meet its contractual obligations in terms of coal supply.

The mine supplied a lesser amount of coal than agreed on to the power utility’s Hendrina power station.

Eskom said it expected 370,000 tonnes of coal per month.

Mammburu said service providers had also been hit hard. "Service providers are owed millions. These are BEE companies, which will be forced to close as they were not paid,” he said.

Meanwhile, Parliament’s portfolio committee on mineral resources has been asked to step in at the mine.

"Optimum coal mine that supplies Hendrina power station in Mpumalanga informed Eskom that they have commenced with business rescue proceedings on Monday February 19," Eskom said.

"In January, Optimum coal mine failed to meet its contractual deliveries to Hendrina power station. This has led to Eskom imposing a failure to supply penalty. The penalty amount exceeded the invoice amount from Optimum coal mine.

Coal has not been delivered to Eskom since workers at the mine downed their tools on Thursday. In mitigation, Eskom has diverted coal from other mines to supply Hendrina power station.

The chairperson of the committee‚ Sahlulele Luzipo‚ said the situation at Optimum mine was reminiscent of the events that occurred leading up to the Aurora mine disaster. There‚ workers were not paid for several months before the mine was shut down and its assets stripped by owners."

It cannot be allowed under this government dispensation that workers are made to bear the brunt‚ while the owners walk away unscathed‚" Luzipo said.

The committee was not convinced by explanations given to the workers by Optimum mine CEO George van der Merwe‚ about the sale of the mine to new owners.

"We call on the Department of Mineral Resources to intervene swiftly and establish with certainty the future of the mine. It should also assist in ensuring that workers are paid‚" Luzipo said.

The committee welcomed a commitment by President Cyril Ramaphosa to go to the mine to find a lasting solution to avoid job losses.