Rio Tinto has reported a 47 per cent increase in diamond production for the second quarter of 2013, largely due to the rise in the number and grade of diamonds processed at its Australian mine.

The company’s Argyle mine in Western Australia – famous for its fancy pink diamonds – produced 3.13 million carats, an increase of 87 per cent. The result was reportedly driven by the new underground mine that began operation in April this year.

Overall, the mining giant processed 4.135 million carats for the period. The figure comprises production at all three of Rio Tinto’s diamond mines.

Production at the Canada-based Diavik mine, in which Rio Tinto owns a 60 per cent stake, decreased 13 per cent to 936,000 carats due to lower grades of ore being mined during the quarter.

Rio Tinto also owns 78 percent of the Murowa mine in Zimbabwe where its share of production grew 21 percent to 69,000 carats.

The company expected to recover 15.7 million carats of diamonds in 2013.

Jeweller has previously reported that Rio Tinto decided to retain ownership of its diamond business in June this year, following an 11-month review of the unit.

In other diamond news, De Beers Group’s auction arm has introduced a forward contract sales model, said to give its rough diamond customers an opportunity to determine the volume of goods they wish to purchase, over a given period.

While it will also continue to hold spot auction events, the new arrangement will enable diamond-buyers to engage in forward planning. Additionally, the division will be relocating its operations base to Singapore in November 2013.

"Offering forward contract sales through our auction platform, and moving the base of our auction sales to Singapore, will further enhance our compelling proposition to a diversified global customer base, support our position as the leading distributor of rough diamonds via online auctions, and deepen our insight into rough diamond demand,” De Beers CEO Philippe Mellier said.

Approximately 10 per cent of De Beers’ rough diamonds are sold through its auction platform – the remainder are traded with the company’s sightholders. The company advises that further details of how diamond buyers can participate in forward contracts will be revealed later in this year.