Impala Platinum's Zimbabwe unit said on Monday metal production fell 13 percent during the July-September quarter after a maintenance shutdown at its furnace, but the company was on track to submit a revised local ownership plan in November.

Zimplats said output of platinum group metals in concentrate had declined to 90,822 ounces compared to 103,874 ounces during the previous quarter.

The furnace was down for 5 days for scheduled maintenance. 4E metal production was thus 13 percent below previous quarter in line with the lower mill and furnace throughput, Zimplats said in a statement.

The platinum miner said a 60 percent rise in electricity tariff on September 1 was higher than expected and would increase production costs in future.

Revenues during the period amounted to $133 million, 9 percent below the previous quarter, due to lower sales volumes.

Zimplats said it was working on a revised local ownership plan which was scheduled to be handed to the Zimbabwean government in November. Its initial document was rejected in September.

Zimplats, which is 87 percent owned by Implats is among several foreign-owned mines in which President Robert Mugabe's government wants to hand over at least 51 percent shares to black Zimbabweans.

Earlier this month, Implats announced that local communities would acquire a 10 percent stake in Zimplats as part of local empowerment compliance measures.