Sibanye-Stillwater workers to strike for R1,000 a month increase NUM and Amcu, the two biggest mine unions in South Africa, have demanded an increase of R1,000 per month over the next three years, similar to the amount Sibanye's rival, Harmony Gold, agreed to pay last year. The Sowetan reports that Sibanye's CEO Neal Froneman said the company would not be revising its final offer, as it could not sustain higher wage increases. "There are no winners in a strike," he said in a statement.