A reduced power supply to South African mines could lead to sharp production losses and thousands of job cuts at Gold Fields, Africa’s second largest gold producer, the company said on Monday.

Gold production was likely to fall between 15 per cent and 20 per cent a year at Gold Fields’ South African mines as long as they were operating on 90 per cent of their normal power supply, the company confirmed, noting that power rationing was expected to last five more years. An estimated 6,900 employees, or 13 per cent of the workforce, could lose their jobs in restructuring, and some shafts could be closed down.