Rio Tinto’s diamond production from the Argyle mine in Australia reached 2.5 million carats in the first quarter of 2010. This compares with diamond production of 3.5 million carats in the final quarter of 2009, or 4.4 million carats in the first quarter of 2009.

The company attributes the reduction in carat production at Argyle to lower feed grade and frequent stoppages of the process plant due to wet weather.

At the Diavik diamond mine, where Rio Tinto holds a 60% share, production during the first quarter of 2010 was 938,000 carats. During the quarter, some 6% of total carats for the period were sourced from underground, after the commencement of production from the Diavik underground mine just a short time ago. The first quarter production from Diavik was 12 percent lower than the same quarter of 2009 primarily due to lower volumes processed, as planned.

Production from the Murowa diamond mine in Zimbabwe, in which Rio Tinto holds a 78% share, was 29,000 carats during the quarter.