Rio Tinto starts underground production at A21 pipe at Diavik diamond mine

Rio Tinto (ASX: RIO) says it’s begun commercial production from a new underground development at its Diavik diamond mine, in the Northwest Territories, after completing the first phase of development and construction at the A21 kimberlite.

The miner greenlit the US$40-million expansion, which will extend the operation’s life to at least early 2026, last year. 

It approved the second phase of A21 underground development earlier this year with an additional investment of US$17 million.  

The initial stage is slated to produce an extra 1.4 million carats, with the second phase adding another 800,000 carats. 

Construction involved the development of over 1,800 metres of underground tunnels to access the A21 orebody.  

Rio said there were no lost time injuries after more than 100,000 labour hours completed over 20 months during the development and construction work.  

“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,” Diavik mine chief operating officer of Matt Breen said in a statement.  

“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,” Breen said, adding that the company  is continuing its investment in preparing for the closure and remediation of Diavik mine site, focusing on progressive reclamation activities such as earthworks, site clean-up, and equipment procurement.  

Diavik is one of Canada’s largest diamond mines in terms of volume of rough diamonds, having produced over 144 million carats of rough diamonds since mining began in 2003.