The production was also down 24% compared to the second quarter ended 30 June 2012.
BHP noted that diamond production was lower than all comparable periods, as a result of the temporarily restricted mining conditions and unscheduled maintenance at its Canadian Ekati mine.
"While production is expected to recover in the December 2012 quarter, it is forecast to remain constrained in the medium term as the operation extracts lower grade material, consistent with the mine plan," the company said.
During the third quarter, BHP Billiton has also completed the sale of its 37% non-operated interest in Richards Bay Minerals, located in South Africa, to Rio Tinto.
The company is continuing an overall review of the diamond business with a 2% decline in metallurgical coal production compared to the third quarter 2011.
