Rio Tinto’s 2007 Diamond Production -26%

Rio Tinto’s diamond production shrunk 26 percent in the past year, to a total of 26.023 million carats. The drop is mostly a result of dwindling production at Rio’s Argyle mine in Australia, which yielded 18.744 million carats in 2007 compared to 29.078 million carats in 2006.

The miner cited continued low feed grade at Argyle as the cause. “Variability in feed grade and production rates is expected to continue as the open-pit operation approaches the end of its life and the mine transitions to an underground operation,” Rio said in a release.

Production at Diavik in the fourth quarter was 18 percent higher than the fourth quarter of 2006 as mining was almost exclusively from the higher grade A154S pipe in 2007 compared with a blend of A154S and A154N pipes in 2006. Production was six percent lower than the third quarter due to the impact of winter weather.

For the year, Diavik produced 7.166 million carats compared with 5.897 million carats in 2006.

Production at Murowa in Zimbabwe, where Rio has a 78 percent stake, fell from 187,000 carats in 2007 to 113,000 carats in 2007.