The Diavik diamond mine has officially opened its A21 kimberlite pipe expansion, designed to keep the mine’s production near current levels through to 2023.

The four-year project to create the mine’s fourth diamond pipe cost roughly $450 million. While the new pipe won’t extend the mine’s life beyond the early 2020s, mine operator Rio Tinto says it will “sustain production levels.”

Rio Tinto employees, representatives of local communities, joint venture partners, and NWT industry minister Wally Schumann attended a ceremony at the site on Monday.

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In prepared remarks, Schumann said: “I have been lucky, over the years, to see time and time again that no matter what phase of development our diamond mines are in, their continued commitment to the North, to its people, and to offering opportunities to our communities and businesses has remained strong.

“I want to thank Diavik for their part in contributing to this legacy and recognize all of the employees – past and present – who have helped get the mine to this important milestone achievement today.”

In a news release, Arnaud Soirat – Rio Tinto Copper & Diamonds chief executive – said building A21 “reflects the strong outlook we see for the diamond industry.”

He added: “It is a remarkable achievement to deliver this project safely and ahead of time in such a challenging environment, positioning Diavik to continue meeting the demand for its outstanding diamonds.”

The world diamond market is recovering from what was widely interpreted to be a tough second half of 2017. Global diamond production is currently forecast to peak in 2019 before gradually dropping.

Diavik, 300 km north-east of Yellowknife entered production in 2003. When development of A21 was formally approved, in 2014, the mine plan set 2023 as the end date for production.

To get at the diamonds contained within the A21 pipe, which was discovered just south of Diavik’s existing operations, workers had to build a dike and drain a portion of Lac de Gras.

The pit is expected to reach full production in the final few months of 2018.

A21’s opening comes in the same month as the neighbouring Ekati mine celebrated its 20th anniversary.

Ekati executives and dignitaries attended a little-publicized function in Yellowknife’s Somba K’e Civic Plaza on Thursday, August 9.