Miners at the Anglo Kleinkopje mine began an unprotected strike on Tuesday morning, halting production over internal issues “specific” to the mine, a spokesman told ft.com.

They report that Anglo said production had resumed at the mine Wednesday, adding that the strike was “resolved by late afternoon” and that the night shift had not been affected.

The action at Anglo follows the breakout of six strikes at Exxaro mines last week, affecting almost half of Exxaro’s workforce.

Two strikes began on March 5 at the company’s Matla and Arnot mines in Mpumalanga. Workers are striking because they did not receive performance bonuses, but Exxaro said the employees were aware of their performance levels and targets, and did not receive the bonus because targets were not met.

Just three days later, employees at Exxaro’s Grootegluk mine in Limpopo began a walk-off. Exxaro said the strike involved “a range of grievances.”

Production also stopped at the Leeuwpan mine from March 9 and Inyada from March 11. Production at the Tshikondeni mine also ground to a halt on March 12 but staff returned to work within 24 hours.

Exxaro said in a statement that production at all of the mines had been suspended as they engaged with unions to manage the situation.

Exxaro has previously stated that it has “adequate stock days of supply” but a prolonged strike could be of serious concern to the Eskom power station and could result in blackouts.

Often-violent labour unrest shut parts of South Africa's mining industry for months last year, and the industry remains anxious about a renewal of the disturbances that left more than 50 people dead and pushed prices higher.