South African miners went on strike at Xstrata Plc
It was not immediately clear how many workers at the Anglo-Swiss miner's South African operations walked off the job when the strike started at 1600 GMT.
It has started, but I am waiting for confirmation from all the operations, Lesiba Seshoka, a spokesman for the National Union of Mineworkers, told Reuters.
The strike will affect all of the diversified miner's South African operations, Seshoka said. The firm has both coal and alloy operations in South Africa.
More workers are likely to walk off the job at the start of Monday's morning shift.
No one was immediately available for comment at Xstrata.
The union wants employees to be compensated equally under the share ownership program, regardless of rank, while the company's plan compensates employees based on their level.
Companies with operations in South Africa set up employee share programs in a bid to increase worker ownership, and particularly black ownership.
South Africa's black economic empowerment drive is aimed at rectifying the ownership and income disparities of white apartheid rule.
(Reporting by David Dolan; Editing by Sophie Walker)