The union members are protesting the suspension of the workers for alleged misconduct and breach of the picketing rules during the six-week legal strike at the site, which ended in October.
Management is in discussion with NUM representatives to resolve the matter and ensure the workers resume their shifts.
Union officials have been told that disruptions and continued strike action will have a severe impact on the mine’s viability and likely result in job losses.
The colliery employs 368 people, with 244 of them union members.
Coal of Africa was forced to call force majeure during the strike earlier this year.
The strike, which began on September 25, was called by the NUM to support its wage claim.
