Striking workers from Anglo American Platinum's (Amplats) Rustenburg mine barricaded a street with burning tyres as a police helicopter hovered overhead and armed officers backed by armoured vehicles and water cannons were on stand-by close by.

 

Amplats, the world's biggest platinum producer, is threatening legal action if the wildcat strikers do not return to work on Thursday.

 

"We'll buy 20 litres of petrol and if police get violent, we'll make petrol bombs and throw them at them," said Lawrence Mudise, an Amplats rock driller, holding up a sign demanding 16,700 rand ($2,000) in monthly pay.

 

Police fired tear gas and stun grenades to disperse a crowd of men carrying spears and machetes in a squatter camp near the site a day earlier.

 

"We'll not go to work until we get what we want. Our kids have been shot at, our families have been terrorised and brutalised, but we are not going back to work," one miner, who did not wish to be named, told Reuters.

 

Last month Lonmin miners from rival unions armed with machetes died in clashes before a standoff in which police shot dead 34.

 

It was the bloodiest security incident since the end of apartheid in the 1990s and sent platinum prices more than 20 per cent higher.

 

Amplats said disruptions at its mine posed a threat to the site's future.

 

"(The) operations are already under considerable economic pressure", it said in a statement. "Any further delays in returning to work will only increase the risk to the long-term viability of these mines."

 

As the return to work began in earnest at Lonmin's Marikana, workers shouted "We are reporting for work" in Fanagalo, a pidgin mix of Zulu, English and other African languages.

 

The miners were in jubilant mood after securing wage rises of up to 22 per cent.

 

"I feel very happy that I can go back to work now," said Nqukwe Sabulelo, a rock-driller at the mine, 100 km northwest of Johannesburg. "I'm going to live well now."

 

Yet like Rustenburg, other mines faced strikes as wage demands spread.

 

Some 15,000 miners at the KDC West operation of Gold Fields , the world's fourth largest bullion producer, are holding an illegal strike.

 

The rank and file are discontent with the local leadership of the dominant National Union of Mineworkers (NUM) but their stance has been given fresh impetus by the Lonmin settlement.

 

Gold Fields said this week it would not entertain demands for a minimum wage of 12,500 rand despite losing 1,400 ounces a day - close to 15 per cent of group production.

 

NUM General Secretary Frans Baleni said the union, a key political ally of the ruling African National Congress, was trying to help.

 

The stand-off threatens the NUM-dominated collective wage-bargaining that has typified South African industrial relations since apartheid.

 

"We are trying to narrow the demands and get them to go back while we negotiate," Baleni told reporters.

 

Economists say the precedent set by Lonmin could spread through an economy already saddled with globally uncompetitive labour costs, stoking inflation and curbing the central bank's ability to cut interest rates to boost sputtering growth.