JOHANNESBURG – South African police and security guards fired rubber bullets and tear gas Monday at sacked gold miners who were attacking colleagues to block them from working, the mine owner said. Police said four people were wounded at the mine that used to be partly owned by the president’s nephew.

The clash at the Gold Fields mine east of Johannesburg, reported by police and Neal Froneman, the CEO of Gold One International, was the latest violence to hit South Africa’s mines in months of unrest.

Company spokesman Sven Lunsche said some 12,000 of the company’s workers “continue to engage in an unlawful and unprotected strike” that began Wednesday. He said it involved an internal dispute between local union leaders and members of the National Union of Mineworkers, the country’s largest union.

After apartheid ended in 1994, South Africa pressed to share the country’s vast mineral wealth with its impoverished black majority. But the hoped-for result has not occurred. A small black elite has become billionaires off mining while most South Africans continue to struggle against mounting unemployment, deeper poverty and a widening gap between rich and poor that makes the country one of the most unequal on Earth.

The mine where the violence took place Monday has previous business ties to relatives of Nelson Mandela and President Jacob Zuma – and was the site where firebrand politician Julius Malema, an avowed enemy of Zuma, pledged last week to make the nation’s mines ungovernable.

South Africa’s mining unrest reached a bloody climax on Aug. 16 when police shot 112 striking workers, killing 34 of them, at a platinum mine at Marikana, northwest of Johannesburg. The state violence has seriously damaged the government’s image.

Outrage at the police killings was exacerbated by prosecutors, who last week charged some 270 miners arrested at the scene with the murders and attempted murders of their striking co-workers. The National Prosecuting Authority was forced to retract Sunday, withdrawing the charges.