Production at the Wonderfontein coal mine has been halted for three weeks after members of AMCU decided to down tools in March. They are demanding their basic monthly salary to be doubled from about $265 (R4,000) to $530 (R8,000), as well as medical aid, transport and housing allowances.

“While the first week of the strike was fairly peaceful, it has turned increasingly violent in the past two weeks, resulting in the obtaining of a court order against AMCU and its members to desist from acts of violence at the mine,” Glencore said in a statement quoted by Reuters.

The union said through its Twitter feed that leaders would meet mine representatives later today following today’s violent incident.

AMCU also plans a strike due to start on Wednesday at Sibanye Gold (JSE:SGL) (NYSE:SBGL) to demand higher wages.

Wonderfontein Coal mine is a joint venture between Glencore and Shanduka Group.