According to reports, workers have downed tools at a mine operated by Anglo American's South African coal unit.
The strike started on Tuesday and was regarded by the company as a wildcat action because the employees had not gone through the proper channels before calling the stoppage on work.
"We are continuing to talk with their regional leadership to settle the differences," said Moeketsi Mofokeng, a spokesman for Anglo American Coal.
The National Union of Mineworkers said in a statement that its members were calling for the removal of the mine's general manager, whom it said had "made lots of changes without consulting" the union.
NUM said grievances with the manager included recruiting changes and safety issues related to loading procedures.
NUM spokesman Livhuwani Mammburu said 421 of its members were involved in the strike, which comes ahead of wage talks in the coal and gold sectors expected to kick off next month.
Edited from source by Joseph Green
Source: Reuters