South Africa’s Northam Platinum has raised its pay offer to encourage workers to end the Zondereinde mine strike, estimated to be costing $1.28m in revenue losses a day.

The country’s National Union of Mineworkers has demanded a 15% wage increase and rejected the company’s earlier offer of a 9.5% increase last week.

About 80% of Northam’s 6,800 employees at its Zondereinde mine have been on strike since 5 September.

The Zondereinde mine produces about 1,000oz of metal including platinum, palladium, rhodium and gold a day.