Rio exits Diavik: closure, rehabilitation and legacy notes for mine planners
Reviewed by Tom Sullivan

First reported on MINING.com
30 Second Briefing
Rio Tinto has produced the final diamonds from the Diavik mine beneath Lac de Gras in Canada’s Northwest Territories, closing a 2003–2026 operation that yielded more than 150 million carats from four kimberlite pipes mined by combined open-pit and underground methods. Economic reserves are exhausted, with the remote site 220 km south of the Arctic Circle accessible only by air and seasonal winter roads, and final rough parcels will be polished and sold through 2026 via Rio’s Select Diamantaires network. Closure and land reclamation, planned since pre-production, will run to 2029 followed by post-closure monitoring, as Gahcho Kué remains the territory’s last operating diamond mine to about 2030.
Technical Brief
- Four discrete kimberlite pipes under Lac de Gras were sequentially mined using combined open-pit and underground methods.
- Orebody geometry beneath a lake demanded water management, frozen-ground conditions and remote Arctic construction logistics.
- Output included predominantly high-quality white stones with a minor proportion of rarer yellow diamonds.
- Closure planning was integrated pre-production, enabling progressive reclamation and a defined 2029 completion horizon.
Our Take
Rio Tinto’s exit from Diavik comes as our database shows its recent newsflow skewing toward long-life, power‑intensive assets like the Boyne aluminium smelter and Resolution Copper, signalling capital and management attention moving away from mature Canadian diamond operations toward base metals and aluminium.
With Diavik closure activities running to 2029 and Gahcho Kué only expected to operate until 2030, the Northwest Territories diamond belt faces a compressed timeline for mine‑closure execution and regional economic transition, which will likely sharpen scrutiny of closure standards and post‑mining land use around Lac de Gras.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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