Rio Tinto's Murowa Diamonds production rose 11% to 98 000 carats in the fourth quarter of 2012 compared to 88 000 carats in the same period in the prior year, according to Rio Tinto's production figures as at December 31, 2012.
Murowa's annual production for the year stood at 313 000 carats, up 9% from 285 000 carats in 2011.
Diamond ore processed in the quarter amounted to 154 000 tonnes, bringing the annual total to 542 000 tonnes.
The mine processed 126 000 tonnes in the first quarter of the year, 120 000 tonnes in the second quarter and 142 000 tonnes in the third quarter.
Rio Tinto is a leading international mining group headquartered in the UK, combining Rio Tinto plc, a London and New York Stock Exchange-listed company, and Rio Tinto Ltd, listed on the Australian Securities Exchange.
The global group owns Murowa jointly with RioZim Ltd, which accounts for the balance of the shares. RioZim is an independent company listed on the Zimbabwe Stock Exchange.
According to Indigenisation minister Saviour Kasukuwere, Murowa is soon expected to relinquish majority shareholding to Zimbabwean locals in line with the country's economic empowerment legislation.
According to media reports, Rio Tinto plans to cede 29% of its stake in the diamond mine to Zimbabwean locals, where 10% would be transferred to a community share ownership trust, another 10% to employees while the balance will be given to the National Indigenisation and Economic Empowerment Fund.
Murowa's operations significantly contributed to the total group diamond production which grew 12% to 1,3122 million carats.
Production at Rio Tinto's wholly-owned Austalian operation, Argyle Mine grew 14% to 8,471 million carats, while the company's 60%-owned Canadian operation Diavik Mine's production rose 8% to 4,338 million carats.
Group diamond output increased 9% year-on-year to 3,248 million carats in the last quarter of 2012, with increases registered at all of its operations.