Mining major Rio Tinto has assumed majority ownership and direct management control of Nemaska Lithium after increasing its shareholding to 53.9%, with the government of Quebec retaining the remaining 46.1% through Investissement Quebec.

The new ownership structure follows equity investments made by the partners since March 2025 and positions Rio as operator of the integrated lithium project, which includes a lithium hydroxide plant in Bécancour and the Whabouchi spodumene mine in the Eeyou Istchee James Bay region.

As majority shareholder, Rio will now assume direct management responsibilities at Nemaska Lithium and apply its internal processes and standards across development, operations, sales and marketing as it advances its lithium ambitions in Canada.

Construction of the Bécancour lithium hydroxide plant reached 60% completion at the end of 2025, with engineering works now complete. Commissioning activities are scheduled to begin in 2026, while first production is targeted for 2028.

The partners have committed additional funding to advance the project. The Quebec government will invest up to $200-million in Nemaska Lithium through equity subscriptions, while Rio will invest more than $300-million in 2026 to continue developing its lithium business in the province.

Rio Tinto Aluminium and Lithium CEO Jérôme Pécresse said the company’s Quebec assets were central to its growth plans in battery materials.

“Rio Tinto’s activities in Quebec play an important role in our ambition to take our world-class lithium business to the next level of growth and performance, notably through Nemaska Lithium. This evolution will facilitate the achievement of this objective and enable us to better support the long-term development of Nemaska Lithium, which will expand our integrated lithium product offering,” he said.

“Rio Tinto remains committed to Quebec and Canada because we believe in the country’s potential to become a leader in the industries of the future, and we are determined to continue developing our assets here to supply the materials the world needs.”

Rio’s increased stake in Nemaska Lithium follows its acquisition of Arcadium in March 2025, through which it secured an initial 50% interest in the Quebec-based lithium business.