Rio Tinto’s Nemaska control and US$300M spend: project notes for mine planners
Reviewed by Joe Ashwell

First reported on MINING.com
30 Second Briefing
Rio Tinto has taken control of Nemaska Lithium with a 53.9% stake and plans to invest more than US$300 million in Quebec in 2026, alongside up to US$200 million in new equity from the provincial government. Capital will advance Nemaska’s 32,000 t/y lithium hydroxide plant at Bécancour, now about 60% complete, and the Whabouchi spodumene mine in the James Bay region, with commissioning at Bécancour targeted for 2026 and first production in 2028. Rio is also assessing feed from its Galaxy mine and Whabouchi to optimise spodumene supply to the plant.
Technical Brief
- Equity structure now 53.9% Rio Tinto and 46.1% Quebec government, affecting control and funding decisions.
- Bécancour lithium hydroxide plant was ~60% complete at end-2025, indicating remaining construction and commissioning scope.
- Nemaska’s Whabouchi project and Bécancour plant form an integrated mine-to-chemical supply chain within Quebec.
- Nemaska previously entered creditor protection in 2019 after cost overruns, implying elevated cost-control scrutiny on current capex.
- Rio acquired its initial 50% Nemaska stake via the ~US$6.7 billion purchase of Arcadium Lithium.
- Group-wide, Rio has flagged US$1 billion per year over three years to expand lithium output in Canada and Argentina, signalling multi-asset pipeline development.
Our Take
Within our 1058 Mining stories, lithium pieces linked to Canada and Argentina increasingly feature multi-asset spending plans, so Rio Tinto’s $1 billion-per-year allocation signals it is positioning Nemaska alongside South American assets rather than as a standalone Quebec bet.
The 60% completion of the Bécancour lithium hydroxide plant, combined with Quebec’s 46.1% stake in Nemaska, likely strengthens the province’s leverage in downstream processing policy, which has been a recurring theme in our Quebec-tagged project coverage.
Rubaya’s relatively modest $50–150 million restart cost, compared with the planned $300 million Quebec investment, suggests Rio Tinto may treat the Congo asset as a flexible, lower-capex option to balance supply risk against its higher-profile North American lithium portfolio.
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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