Workers at Impala Platinum's Rustenburg mine have returned to work, the company said on Thursday, after a two-day stoppage that cost it at least 6,000 ounces in lost output. "Yes, we are back at work," Chief Executive David Brown told Reuters. The operation had been hit by renewed strife stemming from a battle between rival unions. But the situation remains tense, with one of the unions planning to march to a courthouse on Friday, where two of its supporters faces charges of attempted murder. "The march is planned tomorrow and we are preparing for that," a police spokesman told Reuters. The battle between South Africa's dominant National Union of Mineworkers (NUM) and the Association of Mineworkers and Construction Union (AMCU) led to a six-week shut down of Implats' Rustenburg operation earlier this year. The operation is the world's largest platinum mine and the stoppage took 120,000 ounces out of global output.