The union’s call for action comes after the company last week announced that it was tabling a restructuring plan that could see 550 workers lose their jobs.
The colliery has recorded consistent losses for more than a year and the company said it had fought in vain against poor operational performance and the impacts of the global downturn in thermal coal prices.
"This decision follows sustained and concerted attempts over the past two financial years to make the operation profitable and enable it to produce positive cash flows," the company said in a June 3 statement.
"This decision has not been taken lightly as [Coal of Africa] recognises the importance of conserving jobs, but at the same time the need to preserve the company's financial structure and ensure its future sustainability is paramount," chairman David Brown said in a statement.
Mooiplaats recorded a loss of approximately $R167 million ($US62.8m) for the 2012 financial year and has recorded an average monthly loss of $R20 million ($US2m) since the beginning of the current financial year.
The company said it would embark on a regulatory Section 189A two-month consultation process from June 3 to evaluate alternatives to placing the colliery on care and maintenance.
But NUM Secretary of Education Ecliff Tantsi told Eyewitness News the union rejected the proposal and called on officials to intervene.
“If that company cannot operate, then the government must take [away] that licence,” Tantsi said.
The plant was hit by two strikes last year when NUM members protested over poor wages and alleged racism.
Strike action and protests are common in South Africa’s mining industry, which has been the scene of prolonged struggles since mid-last year when a series of wildcat and protected work stoppages disrupted production throughout the country.
