Perth: Rio Tinto recently announced that diamond production for the first half of 2015 increased 18 percent compared to the same period of 2014 – 8,851,000 carats compared to 7,482,000 carats last year.

The company said the increase was due to higher volumes recovered at the Argyle mine in Australia due to the continued ramp up of production from the underground mine. This product jump was enough to offset the lower carats recovered at Diavik in Canada, which saw lower ore availability as mining progressed through an area of higher dilution in the first quarter and the absence of stockpiled ore, which was processed in the first half of 2014.

Gross revenue from diamonds totalled $331 million for the half year ended June 30. This compares to $431 million for the same period of 2014. Net earnings for the six-month period total $31 million compared to $18 million in 2014.

The company sold its 77.8-percent interest in the Murowa mine in Zimbabwe during in June. Looking ahead, Rio Tinto said it is expecting its share of diamond production this year to total 20 million carats.

For the first half as a whole, Rio Tinto reported underlying earnings of $2.9 billion compared to $5.1 billion in the same period of 2014, a drop of 43 percent. Net earnings fell 82 percent from $4.4 billion to $806 million.

Rio Tinto chief executive Sam Walsh said that the figures were “a robust set of results, given the tough operating environment.”