Four miners have been shot and injured, apparently by security guards using rubber bullets at a gold mine owned by the South African president's nephew and a grandson of anti-apartheid icon Nelson Mandela.
Monday's shooting comes after firebrand politician Julius Malema visited the Aurora gold mine last week and told fired mineworkers that he was going to make South African mines ungovernable.
Police spokeswoman Pinky Tsinyane said four miners were shot and that police have arrested four people for public violence.
The shootings come on the day it was announced South Africa was withdrawing controversial murder charges against 270 miners for the killings of 34 striking co-workers shot dead by police.
The National Union of Metal Workers, meanwhile, demanded the suspension of the officers responsible for the shootings.
The announcement follows a barrage of criticism from political parties, trade unions, civil society and legal experts. Even the justice minister had challenged the prosecutor's decision to charge the arrested miners under an apartheid-era law that opened President Jacob Zuma's government to accusations that it was acting like the former brutal white rulers.
Nomqcobo Jiba, the acting director of public prosecutions, did not say why she had reversed her decision to shift the blame from the police to the miners. "The murder charge against the current 270 suspects ... will be formally withdrawn," she told a news conference.
Most of the 270 miners were arrested on August 16 after police opened fire on striking miners, killing 34 and wounding 78. The shootings, the worst display of state violence since apartheid ended in 1994, shocked the nation. Police said they acted in self-defence after the miners shot at them. Most miners were armed with homemade clubs and machetes but police said they recovered several handguns from the scene.
Ten people had been killed in a week of violence over union rivalries that preceded the shootings. Some of those killed were officials of the National Union of Mineworkers, two police officers were hacked to death and two mine security guards were burned alive in their vehicle.
The killings, and the plight of miners who were demanding higher wages, has highlighted the failures of Mr Zuma's government just as he prepares to run for re-election in December as president of the governing African National Congress, a position that would virtually guarantee him another term as president.