Gold output at Gold Fields' operations in South Africa dropped 11 percent in the third quarter due to wildcat strikes and a fire at one of its mines, the firm announced Monday.

“Production from the South Africa region declined by 11 per cent, from 437,000 ounces in the June quarter to 387,000 ounces in the September quarter,” Gold Fields said.

“This decrease includes approximately 30,000 ounces as a result of the fire at Ya Rona (shaft) and approximately 35,000 ounces as a result of the illegal strike action at KDC.”

The impact of the strikes is likely to be felt more in the final quarter as the bulk of the work stoppages occurred in October.

The company estimates that it will see a total production loss of around 145,000 ounces due to industrial actions in the second half of the year, resulting in a loss of revenue of 2.1 billion rand ($237 million; 182 million euro).

About 29,000 of its employees took part in illegal strikes during an unprecedented spate of labour unrest to hit mines across South Africa, a country highly dependent on mining.

Gold Fields, the world's fourth largest gold producer, warned that the strike, coupled with above-inflation pay hikes and rising energy costs, have increased the risk of “a significant restructuring of our South African operations in the near to medium-term.”

Mining firms in South Africa have warned the wave of illegal strikes that ended more than a week ago - with the return to the job by 12,000 Anglo American Platinum workers, - could see most of them forced to shed jobs. - Sapa-AFP