Rio Tinto has completed the development and construction of the A21 underground mine’s first phase, with the major miner now moving the underground mine into commercial production.
A21 is the fourth diamond pipe that lies within the Diavik diamond mine in Canada, which has been operating since 2003.
Rio Tinto announced last year it had approved a $US40 million investment in the first phase of underground mining below the existing A21 open-pit at Diavik, which will extend the operation’s life to at least early 2026, where commercial production will end.
The construction of the A21 underground mine involved the development of over 1800m of underground tunnels to access the orebody and begin underground production.
The first phase of underground mining at Diavik’s A21 pipe is expected to deliver an additional 1.4 million carats of rough diamonds.
Rio Tinto said the project’s first phase had safety as a central priority, with no lost time injuries recorded after more than 100,000 hours were worked over a 20-month period.
The second phase of the A21 underground project was approved earlier this year via an additional $US17 million investment.
Rio Tinto said the project will enable Diavik to maximise its value from its known resources through to closure.
“The A21 underground operation is positive news for our employees, partners, suppliers and local communities in the northwest territories, as it will enable operations to continue through to closure,” Rio Tinto Diavik diamond mine chief operating officer Matt Breen said.
“Rio Tinto’s decision to proceed with Phase 2 is a testament to the excellent performance of our Diavik team in successfully developing the underground mine beneath the previously mined A21 open pit.”