Mining giant Rio Tinto recorded a nine-percent rise on the year in diamond outputin the fourth quarter of 2012 to 3.248 million carats.
Rio Tinto said that compared to the third quarter, however, there had been a decline of 12 percent from 3.706 million carats.
For all of 2012, production jumped 12 percent on 2011 to 13.122 million carats.
At the miner's 100 percent-owned Argyle mine in Australia, production rose 5 percent to 2.01 million carats, boosted by an increase in tonnage processed and higher grade ore. For all of 2012, there was a 14-percent increase to 8.471 million carats.
"Construction of the underground mine is proceeding and production is scheduled to commence in the first half of 2013, with ramp up to full operation to be completed by 2015," Rio Tinto says in a statement.
Meanwhile, at the Diavik mine in Canada's NorthWest Territories, where Rio Tinto has a 60 percent stake, production soared 19 percent to 1.141 million carats from 961,000 carats a year earlier due to better grades balancing out the smaller volume of tons processed. For the year, output climbed 8 percent to 4.338 million carats.
Finally, the miner's 78-percent holding in the Murowa mine in Zimbabwe saw an increase of 11 percent on the year to 98,000 carats in the quarter, and a 10-percent jump to 313,000 carats for all of 2012.
Harry Winston owns the other 40 percent in Diavik and may purchase Rio Tinto’s stake in the mine, according to comments to the Bloomberg news agency by Harry Winston Diamond Corp's Chief Executive Officer Robert Gannicott http://tinyurl.com/as6j9bw