Gahcho Kué diamond mine operator De Beers says the mine is expected to close in 2028 and work toward its closure is beginning.
De Beers had said in February it was pausing a key expansion designed to keep the mine operating until 2030. The company blamed “the prevailing market environment.”
The natural diamond industry has been hit by tariffs and lab-grown alternatives, and the NWT’s other active diamond mine – Ekati – is also struggling.
De Beers has not previously set out clear expectations for Gahcho Kué’s remaining mine life if that expansion, known as Tuzo Phase 3, does not ultimately go ahead. But the company did include a timeline in an annual report filed with regulators.
“De Beers intends to initiate approved closure activities, where practicable, while the mining fleet and personnel remain present at the mine site. This will allow for efficient material movement, continuity of the workforce, and commencement of required progressive closure activities without delay,” one section of the annual report states.
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“Without Tuzo Phase 3 in the mine plan it is anticipated that GK will remain in operations until 2028.
“De Beers is advancing closure planning activities to minimize the gap between cessation of operations and commencement of closure activities.”
The news that Gahcho Kué may have less than two years in operation comes as Mountain Province Diamonds – which owns just under half of the mine in a joint venture with De Beers – reported 2025 financial year losses of $280 million, more than three times the loss Mountain Province recorded in 2024.
“During 2025 and into 2026, diamond market conditions deteriorated significantly,” Mountain Province stated in a financial results summary.
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“The market was further impacted in Q4 2025 by excess supply of rough diamonds, resulting in short-term dislocation and additional pressure on pricing. In response, and as announced on February 9, 2026, the joint venture partners elected to pause the Tuzo Phase 3 project in order to preserve liquidity and maintain operational flexibility.”
It’s possible that Tuzo Phase 3 could be reintroduced to the mine plan, extending Gahcho Kué’s life back to 2030 or beyond. However, there has been nothing in recent market conditions to suggest the kind of economic turnaround that would drive that decision.
About 850 people were working at Gahcho Kué in late 2025 according to figures provided by mine management, including 600 staff and 250 contractors.
In February, De Beers said it was talking to about five percent of the mine’s employees “regarding redundancies” after announcing the Tuzo Phase 3 pause.
