Diavik Diamond Mine expects to sustain productivity for the next four years after tapping into a new source of diamonds last week.The A21 kimberlite pipe was officially opened at a ceremony held Aug. 20 in front of government and Indigenous leaders, stakeholders and Rio Tinto employees.

The pipe, which cost the mine close to $450 million U.S. and took close to four years to construct, should sustain production levels at the mine until 2025.

"To date, over 100 million carats have been produced from this mine, which has meant the creation of thousands of Northern jobs and the development of supporting industries and businesses that have strengthened and shared the NWT economy," stated Wally Schumann, Infrastructure, Tourism and Investment minister, said at a ceremony at the site.

While the new pipe is designed to allow Diavik to maintain its current production levels, it won't expand the mine's lifespan.

Tom Hoefer, executive director of the NWT and Nunavut Chamber of Mines, said the pipe will keep the mine from gradually slowing down until it closes.

"I think (the opening) is a big moment for the NWT because it allows Diavik to run at a higher level of production near the end of the mine's life," said Hoefer.

The first raw ore has already been produced from the pipe ahead of schedule, however it isn't expected to reach full capacity until late 2018.

"It is a remarkable achievement to deliver this project safely and ahead of time in such a challenging environment," stated Arnaud Soirat, Rio Tinto Copper and Diamonds' chief executive, in a news release.

Once the pipe is fully operational, Hoefer expects there will be number of new jobs created at the mine, which has converted to underground versus the open-pit mining of years ago.

The pipe will produce diamonds from the bottom of Lac De Gras, the lake that the mine is located on.

In order to reach those gems, Rio Tinto has spent the last four years creating a dike that drained six billion litres of water from the lake.

Due to territorial regulations, once the pipe is closed in seven years there will be minimal to no lasting environment damage done to the lake, according to Hoefer.

"They have an environmental monitoring board for that mine," said Hoefer.

"So they're following 'no net loss of fish habitat.' If you take water habitat, you replace it.

So at Diavik, they're just borrowing that lake bottom."

Hoefer said the mine will refill the lake with monitored water and fish populations that will allow for re-population to appropriate levels after the mine is shut down.

Rio Tinto is the majority owner of the Diavik diamond mine with Dominion Diamond Corporation, which was taken over by The Washington Companies in 2017, holding a minority stake.

The mine is located approximately 300 kilometres north-east of Yellowknife. It currently mines close to seven-million dollars worth of diamonds annually.