Perth: Rio Tinto recorded a 6 percent increase year over year in diamond revenues grossing $901 million for the year ended December 31, 2014. The group’s net diamond earnings for the year jumped to $104 million, from $53 million a year earlier. The diamond division has also posted a 23 percent year-over-year increase in EBITDA to $315 million.

Rio Tinto’s diamond production in 2014 decreased 13 percent year over year. The lower carat recovery at Argyle is attributed to the move from open pit to underground mining, the processing of lower grades as underground production ramped up and a maintenance shutdown during the fourth quarter impacting both underground crushers. Regarding operational growth during the year, Rio’s Argyle underground mine remains on track to reach full capacity in 2015.

Production at the Diavik mine in Canada’s Northwest Territories, of which Rio owns a 60 percent share, was in line with 2013, with improved mining rates and processing plant improvements offset by the impact of lower grades. In November 2014, Rio approved the development of the A21 pipe at Diavik, which will provide an important source of incremental supply to maintain existing production levels. A21 is estimated to cost $350 million, with Rio Tinto’s share totaling $210 million, with first production expected in 2018. Rio Tinto’s diamonds production is expected to be 21 million carats of diamonds in 2015.