Perth: Rio Tinto announced that production increased to 4.696 million carats in the second quarter, compared to 3.832 million carats in the same quarter of 2014.

Rough diamond production in the first half of the year totaled 8.851 million carats, up from 7.482 million carats in 2014.

The company said that production at the Argyle mine in Australia was 37-percent higher than in the second quarter of 2014 (3.374 million carats compared to 2.459 million carats) and 34-percent higher than the first half of 2014 (6.591 million carats versus 4.920 million carats), due to the continued ramp up of production from the underground mine.

Elsewhere, production dropped. Rio Tinto’s 60-percent share of production from the Diavik mine in Canada dropped to 1.285 million carats, versus 1.290 carats in the second quarter of 2014. However, compared to the first quarter of the year, production increased 43 percent due to higher grades.

The first half of the year also saw a decline, down from 2.409 million carats in 2014 to 2.183 in the first half of 2015.

Rio Tinto said the reduced production reflected 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.

The miner’s share of production from the Murowa mine in Zimbabwe, which it sold in June, fell 56 percent to 37,000 carats, down from 83,000 carats in the prior year period.