Rio Tinto’s rough-diamond production grew 4 percent to 18 million carats in 2016, the lower end of its guidance, as it continued to step up underground operations at its Argyle mine in Australia.
Output at Argyle, known for its production of rare fancy pink diamonds and high volume of lower-quality rough, increased 4 percent to 14 million carats.
Production at the Diavik mine in Canada rose by the same proportion with Rio Tinto’s 60 percent share amounting to 4 million carats. The increases at both mines resulted from higher ore throughput partially offset by a lower recovered grade, the company explained.
Rio Tinto plans to expand its diamond mining operations, chief executive officer Jean-Sebastien Jacques said in December amid long-running speculation it would sell the business. The company earlier sold the Murowe mine in Zimbabwe and suspended development of the Bunder diamond project in India.
The miner forecast production will rise to between 19 million and 24 million carats in 2017.
Rio Tinto has full ownership of the Argyle mine, with underground mining introduced in 2013 to increase the project’s lifespan to at least 2020. The group also holds a 60 percent share in Diavik, with Dominion Diamond Corp. owning the rest.