Tiwai Smelter To Get New $50M Waste Facility
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A new $50 million processing plant at Tiwai Point will allow the New Zealand Aluminium Smelter (NZAS) to treat waste from its aluminium production on site for the first time, reducing the need to export materials overseas.
Rio Tinto announced the major investment as part of its ongoing long-term remediation programme at the Tiwai site in Southland. The new facility will handle spent cell liner (SCL), a by-product of the aluminium smelting process. Until now, SCL has been stored on site or shipped to Australia for treatment by specialist processor Regain.
“Our new facility at Tiwai Point means this processing will now take place in New Zealand, reducing the need for this processing to happen overseas and forming a key part of the long-term remediation plan for the Tiwai site,” said Rio Tinto | NZAS acting general manager Matt Black.
The SCL currently stored in a specially designed encapsulated pad will be progressively excavated, treated, and exported for reuse, mostly in the global cement industry. Once built, the new plant will be operated by Regain Services Ltd, which already runs a similar facility in Australia.
The project is expected to create 20 jobs during construction and six permanent roles once the facility is operational. All necessary consents have been granted, with construction planned to begin in the second quarter of 2026.
“This significant investment reflects Rio Tinto | NZAS’ long-term commitment to responsible site stewardship and partnerships across Southland,” said Mr Black.
He added that the initiative is part of a broader remediation strategy co-designed with Ngāi Tahu, which includes safe management and recycling of legacy materials, monitoring, and eventual restoration of the land.
“Our partnership with mana whenua is central to how we operate at Tiwai. This project reinforces the principles of protection, participation and partnership that underpin our work together, and supports the long-term future of the site as we continue producing some of the world’s lowest-carbon aluminium,” Mr Black said.
Rio Tinto Managing Director of Pacific Operations Armando Torres said: “This significant investment in the smelter at Tiwai underscores our commitment to the remediation programme we are undertaking with our iwi partners, along with our goal of continuous positive stewardship of the land we are privileged to operate on.”
Te Rūnanga o Ngāi Tahu Group Head of Strategy & Environment Jacqui Caine said: “Building a dedicated processing facility at the smelter is another positive step forward in the remediation of the Tiwai site and reflects our shared commitment to working in partnership to protect our environment for future generations.”
Since 2024, more than 36,000 tonnes of SCL have already been exported for reuse. Other legacy materials such as ouvea premix and historic dross have also been addressed as part of the clean-up.