Police fired tear gas and rubber bullets to disperse the protesters, and sporadic scuffles continue, Capt. Dennis Adrio with the North West police told CNN.
Police and firefighters responded after a power substation on Anglo American Platinum's property was set on fire at 4 a.m., Adrio said.
Tuesday's clashes continued a wave of wildcat strikes and violent confrontations that has wracked the country's mining sector for more than two months, the worst labor unrest since the end of apartheid.
Anglo-American Platinum fired about 12,000 striking workers who refused to attend disciplinary hearings earlier this month after a three-week walkout.
Another company, Gold Fields Limited, fired 8,100 striking workers last week after they did not return to work. Some 15,000 workers at the company's KDC East mine, near Johannesburg, had gone on strike to seek higher pay, as have workers at several other South Africa mines.
Repeated clashes have occurred since police opened fire on strikers Lonmin's Marikana platinum mine in August, killing 34 workers and wounding dozens more.
South Africa's mining sector is the country's biggest industry.