Labour unrest in South Africa shows no sign of ending, with more clashes between police and striking miners.
Teargas and rubber bullets were used to disperse about 1000 men marching on an an Anglo American Platinum mine near Rustenburg, about 120km northwest of Johannesburg.
The strikers responded with petrol bombs and four people were arrested.
About 100,000 minsters and other workers have been on strike since August. Large parts of the platinum and gold mining industries are at a standstill.
Kumba Iron Ore said on Friday it would seek criminal charges against strikers occupying a mine at Sishen.
The strikers have seized about 3.3 billion rand ($US380 million) worth of heavy equipment, including 88 haul trucks and 13 pieces of other equipment, including bulldozers.
Standard & Poor's cut South Africa's credit rating to -BBB with a negative outlook on Friday, saying the strikes and social tensions could reduce fiscal flexibility and damage growth.
More than 50 people have been killed in the last two months, including 34 at the Marikana platinum mine on 16 August.
The mining industry accounts for around 20% of South Africa's GDP.