Workers protest issues of progressive policies, dismissals
Livhuwani Mammburu also told Reuters that 5,200 workers were involved in the strike at Northam's Zondereinde mine in South Africa's northern Limpopo province. The wildcat strike began with the night shift on Tuesday.
"The management there wants to reverse all progressive policies. There was a white female employee hired without following proper procedures," Mammburu said.
South African companies are required by law to give preference in hiring to blacks and other racial groups that were previously disadvantaged under apartheid.
"Workers are also subject to unfair dismissals for being on valid sick leave," Mammburu said.
He added that management had refused to meet with workers on these issues, which forced them to embark on the wildcat action, and that the strike would continue until such a meeting took place and the matters were resolved.
A company spokeswoman said it had received the union's grievances and was urging the strikers to return to the shafts.
"The company's position is that there is a recognition agreement in place to deal with such issues when they arise," she said.
South Africa's mines were hit in 2012 and 2013 by waves of illegal or wildcat strikes undertaken by NUM's arch rival, the Association of Mineworkers and Construction Union (AMCU), which is widely regarded as the more militant of the two.
The current Northam strike may be an indication that NUM is becoming more radical to head off competition from AMCU, which has poached tens of thousands of its members on the platinum belt in a brutal turf war that has killed scores of miners.
Northam has had its share of labour strife. More than 7,000 NUM members went on an 11-week wage strike that ended in January last year at the mid-tier platinum producer.
Output at Zondereinde fell 18 per cent to 1.7 million tonnes in the 2014 financial year because of that labour stoppage.
The wider platinum industry is still recovering from a sometimes violent five-month strike last year by AMCU, which hit Anglo American Platinum, Impala Platinum and Lonmin, the world's top producers of the precious metal used for emissions-capping catalytic converters.
Northam shares were down 3.75 per cent, outperforming a 5.4 per cent drop in South Africa's Platinum Mining index.