Rio Tinto will slow work at the nemaska lithium processing plant in Quebec because rising costs could delay commissioning. The company is expected to withdraw many contractors and keep only a minimal number of staff on site in the coming weeks (ET). The decision comes after Rio Tinto increased its ownership and outlined planned investments alongside the Quebec government.
What happened and why it matters
Rio Tinto will scale back construction at the Bécancour conversion facility, halting much of the on-site workforce and leaving a reduced team to maintain the site. The facility was roughly 60% complete at the end of last year and was designed to produce about 32, 000 tonnes of lithium hydroxide annually once commissioned. Rio Tinto increased its stake in Nemaska to 53. 9% in mid-February (ET) and signaled a planned investment of $300 million in the Quebec operation; the Quebec government holds the remaining 46. 1% and pledged $200 million.
Nemaska Lithium project scope and supply options
The Bécancour plant is part of a fully integrated spodumene-to-lithium plan anchored by the Whabouchi deposit in the James Bay region. That broader scheme was designed as a 26-year operation producing 200, 000 tonnes of concentrates annually and was intended to feed the conversion plant at Bécancour. Rio Tinto entered the project through its acquisition of Arcadium and is reviewing whether Whabouchi is the optimal spodumene supply for Bécancour compared with another hard rock option in the same region. That evaluation is expected to be completed in the first half of 2026 (ET).
Immediate reactions from the players
Rio Tinto has made public its plan to invest $300 million in the Quebec operation and has taken majority control of the Nemaska project. The Quebec government has pledged $200 million to the project. Company officials have begun reviewing supply and development choices for the integrated project while managing the near-term construction slowdown at the Bécancour site.
Quick background
Commissioning of the Bécancour plant had been planned for this year (ET), with first production originally expected two years after that schedule. The plant’s conversion capacity and the upstream concentrator strategy were central to the integrated plan that links Whabouchi concentrates to the Bécancour conversion facility.
What’s next
It remains unclear how the construction slowdown will affect the overall timeline for the project; building activity at the site is expected to fully restart in 2027 (ET). The outcome of Rio Tinto’s supply evaluation, due in the first half of 2026 (ET), will shape whether the operation leans on the Whabouchi deposit or shifts toward the Galaxy hard rock option. Stakeholders will watch capital flows from Rio Tinto and the Quebec government and any updates to the commissioning plan for nemaska lithium as the company balances rising costs against its stated investment commitments.
