Cape Town — Tens of thousands of South African miners held a one-day strike today in support of demands for safer working conditions.

The National Union of Mineworkers (NUM), with 270,000 members the country's biggest union, said it expected all its members to stay away from work.

It planned a march of 40,000 from a traditional labour rallying point in Johannesburg to the nearby head office of the Chamber of Mines, the employers' umbrella body. There would be other protests around the nation, it added.

Addressing a union rally on Sunday, a leader of the Congress of South African Trade Unions (Cosatu) said an average of 200 workers were dying in mine accidents every year.

"Almost daily, families hear the news that a husband, a father, a brother - a breadwinner - has been suddenly taken from them," Cosatu deputy general secretary Bheki Ntshalintshali said.

The Chamber of Mines said in a statement that it had reached an agreement with the NUM last week on initiatives to improve safety. The agreement provided for today's "national protest," although it would be held on a "no-work no pay" basis.

"Parties committed themselves to engage early in 2008 at senior level to develop pledges and actions that will, among others, strengthen and complement initiatives ... to respond to all areas of concern on health and safety on the mines," the chamber added.

But the union accused the employers of making "a lot of empty commitments ... The NUM agrees with the Chamber... that it is our collective responsibility to change the status quo. However, employers need to take a leadership role and invest in safety in the same manner they invest in production."