Speaking overall about the company’s fourth quarter production results, Rio Tinto chief executive J-S Jacques said “We have delivered a strong operational performance in 2016, underpinned by our drive for efficiency and maximising cash flow. Our disciplined approach remains in place in 2017, with the continued focus on productivity, cost reduction and commercial excellence. This will ensure that we continue to deliver value for our shareholders.”

Rio Tinto’s diamond division saw production at the Argyle mine up 4 percent in 2016 (13.9 million carats) from 2015, following the ramp-up of the underground mine, with higher ore throughput partially offset by a lower recovered grade. Production at the mine during the fourth quarter of 2016 was up 6 percent to 3.58 million carats.

At the Diavik mine, carats recovered in 2016 were 4 percent higher than 2015 due to higher ore throughput offsetting lower grades. In the year Rio Tinto’s production at Diavik was 3.9 million carats. In the fourth quarter of 2016, Rio Tinto’s production at Diavik stood at 0.99 million carats, up 10 percent on y-o-y basis.

The company noted that diamond production guidance for 2017 is 19 to 24 million carats.