Firestone Diamonds said its Liqhobong mine in Lesotho remained without sufficient power following outages reported more than a week ago.
The company said it had initiated contingency measures to restore power by alternative means within the coming weeks.
'In the meantime the company will continue to engage with both the Lesotho Electricity Compan and ESKOM, South Africa's power utility, to try to resolve the interruption of grid power to the mine,' it added.
Firestone Diamonds said it had placed an order to hire diesel generator units with which to run the mine's processing plant.
The units were scheduled to arrive on site by the end of October and be fully operational shortly thereafter, during early November.
The generators were expected to be used to generate power until grid power was restored from the Muela hydropower station, which the company had been informed would take place on 1 December.
Normal operating costs were expected to increase by the cost of renting the gensets and of the associated diesel consumption.
At 2:35pm: (LON:FDI) Firestone Diamonds PLC share price was -0.05p at 0.53p