Recovery of lower-grade ore at Rio Tinto’s Argyle and Diavik mines led to a 17% drop in production in the third quarter.
Output came to 4.9 million carats for the three months ending September 30, the company said Tuesday. The Argyle asset in Australia yielded 3.8 million carats, plummeting 19% over the same period last year. Last year, Rio Tinto’s production was enhanced by the processing of higher-grade alluvial tailings, the miner said.
Lower-grade ore also affected production at Diavik, where Rio Tinto’s share of the goods fell 9% to 1.1 million carats. The miner owns a 60% stake in the Canadian asset, with Dominion Diamond Mines holding the remainder, and the companies split the output accordingly.
Diavik’s A21, a fourth pipe located just south of the mine’s existing operations, officially opened in August. Ore extraction began in March, with the owners expecting to reach commercial production during the fourth quarter.
Carat recovery at Argyle slipped 1% in the first nine months of the year, reaching 10.9 million carats, while production at Diavik slid 4% to 3.3 million carats for the period. Total yield for both mines dropped 2% to 14.1 million carats.
The miner expects to produce 17 million to 20 million carats for the year, compared to 21.6 million carats last year.
Image: Rio Tinto’s Argyle mine, Western Australia. (Rio Tinto)