The strikes that began in South Africa’s gold and platinum mines has spread to the iron ore sector of that country where miners have gone on strike at Kumba Iron Ore, a unit of global miner Anglo American.

South African President Jacob Zuma is under fire for failing to address and contain the workers' protests, which stem in large part from glaring wealth inequalities persisting in South Africa since the end of apartheid in 1994.

Reuters reported that as many as 75,000 miners, or 15 percent of the South African mining sector’s total workforce, are already out on strikes, while a national truckers’ stoppage is squeezing fuel suppliers.

Kumba, one of the world’s top 10 iron ore producers, said the wildcat strike at its giant Sishen Mine in the Northern Cape involved only 300 employees and was limited to one area in the openpit mine, leaving most of the facility unaffected.

“The action is being dealt with in line with the company’s labor relations procedure, with due consideration to the safety of the vast majority of workers who are not taking part in the unprotected strike,” Kumba said in a statement.

The recent weeks of labor strife, in which around 50 people have been killed, have stirred up criticism of the ruling African National Congress and the presidency of Zuma, who faces a challenge from ANC rivals ahead of a party leadership conference in December.

Kumba was regarded as immune to the strike contagion because rank and file employees there in December who had worked for at least 5 years were given a lump sum of about 345,000 rand ($41,200) each after taxes as part of a share scheme.

This represented a fortune to workers earning as little as 7,000 rand a month. But it was not immediately clear if any of the 300 reported strikers were among the 6,200 who had benefited from the plan.

Kumba produced 41.3 Mt (45.5 million st) of ore in 2011.

Seven weeks of labor unrest and strikes, which originally erupted at Lonmin's Rustenburg operations, have now spread across the South African mining industry.

The world’s No. 1 platinum producer Anglo American Platinum is also grappling to resolve a strike at its Rustenburg operations in the country’s platinum belt about 120 km (75 miles) northwest of Johannesburg. Worker attendance at Amplats’ Rustenburg mines has fallen to below 20 percent.

Some 21,000 Amplats workers have joined the illegal walkout.

Fifteen thousand miners at Gold Fields KDC West mine downed tools on September 10, hitting production at the world's fourth-biggest bullion producer. Gold Fields bosses have refused to negotiate with them.

The spreading labor unrest has raised fears the country could see a repeat of the stand-off with police at Lonmin’s platinum mine in August that led to the shooting of 34 miners.

It was South Africa’s bloodiest security incident since the end of apartheid in 1994, and an official commission of enquiry has started a probe this week into the killings.