Lower mining grades and reduced ore availability contributed to a drop in Rio Tinto’s third-quarter diamond production, the company reported Wednesday.
Output at its wholly owned Argyle mine in Australia fell 7% year on year, yielding 3.6 million carats in the three-month period ending September 30. Production was hampered by lower grades, despite stronger mining and processing rates, Rio Tinto said.
Rio Tinto’s share of production at the Diavik mine in Canada also shrank 7% to 994,000 carats for the same period due to lower ore availability both underground and at the A21 extension pipe it opened in August last year. The company owns 60% of the deposit, with Dominion Diamond Mines holding the remainder.
Rio Tinto’s total diamond production, including its share of Diavik goods, dropped 7% to 4.5 million carats.
For the first nine months of the year, the miner produced 12.8 million carats, compared to 14.1 million in the same period of 2018. Its 2019 forecast remains unchanged at 15 million to 17 million carats, down from 18.4 million carats last year.