Diavik Diamond Mine

A diamond mine beneath a northern lake

Diavik was a remote diamond mine beneath Lac de Gras in Canada’s Northwest Territories, about 220 kilometres south of the Arctic Circle. Its four kimberlite pipes were discovered in 1991, and commercial mining began in 2003. The mine used both open-pit and underground methods, extracting from deposits beneath and around the lake. This is an industrial history, not a visitor itinerary: the site sits in a sensitive northern environment, far from ordinary roads and communities, and it is not presented by its operator as a public attraction. Its current story is now one of closure, reclamation and long-term monitoring.

On March 26, 2026, Rio Tinto announced that Diavik had reached its final day of production after 23 years and more than 150 million carats of rough diamonds. The company said economically recoverable reserves had been exhausted. Most of the output was white gem-quality diamonds, with a smaller proportion of yellow stones. The last mined production does not mean all activity stopped on that date: the remaining rough diamonds are to be polished and sold through Rio Tinto’s customer network during 2026 and beyond, while workers continue closure tasks at the site.

How the mine changed over its operating life

Diavik’s unusual location made engineering and logistics part of its defining story. The ore bodies lie beneath Lac de Gras, and the mine relied on a combination of open pits, underground workings and water-control structures. Rio Tinto describes the region as remote and ecologically sensitive. The distance from major centres, seasonal access conditions and harsh northern weather shaped how supplies, staff and equipment could reach the operation. These conditions are reasons not to approach the area independently; they are also why closure planning had to be considered before the first production began, rather than treated as an afterthought.

The project was developed with Indigenous partners and governments in the Northwest Territories. Rio Tinto reports that its partnership agreement with the Tłı̨chǫ Government began in 2000, before production, and involved employment, training, contracting and community investment. Tłı̨chǫ Elders and community members have also contributed Traditional Knowledge and feedback during construction, operations, closure planning and remediation. Such details belong to the documented project history, but they should not be reduced to a claim that all community views are identical or that the mine’s benefits erased its environmental obligations.

Closure is a multi-year project, not a single event

Production ended in March 2026, but physical closure work is expected to continue through 2029, followed by post-closure monitoring. The Mackenzie Valley Land and Water Board’s decision on the Final Closure and Reclamation Plan addresses objectives and criteria for safety, land use, landforms, water, biodiversity, infrastructure and security. The Government of the Northwest Territories’ published monitoring documents distinguish the active-closure period from post-closure monitoring, currently laid out through 2034. These are plans and regulatory milestones, not proof that the landscape has already been restored or that every future outcome is settled.

One central task is managing the mine’s engineered relationship with Lac de Gras. The approved closure plan considers the pits, underground workings, dikes and processed-kimberlite containment facility, among other components. Reclamation must address water quality, stable landforms, wildlife and future land use, and must meet criteria agreed through the regulatory process. Rio Tinto says the work will proceed with the territorial government and Indigenous partners. Readers should distinguish those commitments and targets from completed results: monitoring will continue after active work, and public records may change as regulators review new plans and reports.

What a traveller can—and cannot—see

Diavik is not a tourist mine and is not open for self-guided visits. Its northern location, industrial infrastructure, closure work and access controls make an unplanned journey inappropriate. The sources reviewed for this guide do not advertise public tours, visitor hours or an on-site museum. The responsible way to learn about the place is through Rio Tinto’s project information, Tłı̨chǫ Government communications and the public regulatory registry. Anyone travelling in the Northwest Territories should plan around designated public destinations and current road or aviation information, not use mine coordinates as a route to a restricted workplace.

Diavik’s significance is best understood through the contrast between a finite mining operation and the responsibilities that last beyond production. Discovery in 1991, first production in 2003 and the final production day in March 2026 provide a clear timeline; the closure agreement and regulatory plan show how the next chapter is being organized. More than a mine statistic, the site is a place where industrial decisions intersect with northern ecosystems, Indigenous partnerships and long-term stewardship. That history deserves careful attention: the mine has stopped producing diamonds, but its closure, monitoring and relationship with the land and communities remain unfinished work.