Workers plan to walk off the job tonight in South Africa’s diamond mines, the latest in a string of strikes affecting South Africa’s mining sector, according to a report in Business Week.

Diamond workers are expected to put down their tools following demands for higher pay and more time off, the report said. Glencore Xstrata Plc mining employees walked out in May.

Discussions between De Beers, a unit of Anglo American Plc and union representatives have continued since the strike notice was delivered July 3, the report said.

The National Union of Mineworkers demands a 13 percent wage increase, while the company has offered 6 percent, according to the union. Workers are also seeking more time off.

Strikes are expected in Voorspoed in Free State province, Kimberley in Northern Cape province and Venetia in Limpopo province. Talks will continue, said Peter Bailey, a negotiator for the union, in the Business Week report. The action will affect the company’s trading arm, Diamond Trading Co.

De Beers Consolidated Mines has 2,550 employees with 1,300 represented by the union, according to Business Week.

De Beers’s South African mines account for about 16 percent of the company’s total carats recovered. The company also has operations in Botswana, Canada and Namibia.