Rio Tinto’s diamond output down 14% in 2014

Diavik mine is located in Canada’s diamond-rich and remote North West Territories.

Rio Tinto’s (ASX:RIO) total rough diamond output fell 14% in 2014 from a year earlier due mainly to the transition of its Argyle mine in Australia from open pit to underground, as well as a shift toward processing lower-grade ore at its Canadian Diavik mine.

The main declines were registered in the forth quarter, with output dropping 37% to 2.841 million carats, the company said Tuesday.

Production at Argyle dropped 43% to 1.813 million carats during the quarter. Rio Tinto’s 60% stake in Diavik’s production fell 25% to 927,000 carats after improved processing rates at the mine’s treatment plant fully exhausted its stockpile of higher-grade ore in the previous quarter.

The company’s 78% share of output at the much smaller Murowa mine in Zimbabwe tumbled 4% to 101,000 carats.

Last week, the company said it expects to invest $500 million in its Bunder diamond mining project in the central Indian state of Madhya Pradesh. The mine is expected to generate about 30,000 jobs and produce up to three million carats a year.