Rio Tinto reports that its diamond production for the third quarter of 2013 totaled 4.158 million carats, a 12 percent increase in volume year over year and a slight 1 percent increase in volume compared to the second quarter of 2013.

Third Quarter

At the miner's wholly owned Argyle mine in Western Australia, rough diamond production for the third quarter, totaling 3.085 million carats, was 26 percent higher year over year, reflecting increased tonnes processed in the period and higher grades following commissioning of the underground operation at the end of April, which will extend the life of the mine until at least 2020. Compared to the second quarter of 2013, production was down 1 percent.

The miner's share of diamond production from the Diavik diamond mine in Canada's Northwest Territories, of which it holds a 60 percent interest, totaled 1.003 million carats in the third quarter, down 13 percent compared to the corresponding quarter in 2012. According to Rio Tinto, carat recovery was lower than in the third quarter of 2012 as a result of lower grades of ore mined during the third quarter of 2013. However, diamonds recovered in the third quarter were 7 percent higher than in the previous quarter of 2013 due to the ramp up of underground mining and higher grades recovered.

At the Murowa mine in Zimbabwe, of which Rio Tinto owns a 78 percent stake, production fell 24 percent year over year but grew 2 percent quarter over quarter to 70,000 carats.

Nine Months

For the first nine months of the year, Rio Tinto saw a year-over-year increase of 17 percent in rough output to 11.529 million carats. At Argyle, production grew 27 percent to 8.205 million carats, while at Diavik Rio Tinto's share of production fell 3 percent to 3.106 for the nine-month period. Murowa output grew by a slight1 percent to 217,000 carats.