Rio Tinto New Zealand Aluminium Smelter has revealed a $50 million investment to build a new facility at Tiwai Point.
The facility will handle spent cell liner (SCL), which is a by-product of aluminium production. Traditionally, SCL has been stored under cover in sheds and on a specially designed pad at the site.
In early 2020, hundreds of Mataura residents were evacuated amid fears that flooding could reach the 9500 tonnes of ouvea premix from Tiwai Point, stored by contractors in the town’s former paper mill.
The then-Rio Tinto global chief executive Jakob Stausholm travelled to Wellington in 2021 to apologise to the government for the company’s management of waste from the smelter.
The global chief executive also pledged commitments toward the clean-up.
Since January 2024, NZAS has partnered with specialist processor Regain to safely treat SCL in Australia, allowing it to be reused in the global cement industry.
“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,” Rio Tinto NZAS acting general manager Matt Black said.
According to Black, the previously stored SCL in the encapsulated pad will be gradually excavated, processed at the site, and then exported for reuse.
All required consents for the facility have been secured, with construction slated to start in the second quarter of 2026. Once operational, Regain Services Ltd will manage the plant.
“Processing SCL on-site is a milestone in delivering on the remediation commitments we have made to Ngāi Tahu and our community,” Black said.
“It means we’re reducing waste, improving environmental outcomes, and ensuring legacy materials are safely managed and put to use again in other industries.
“The initiative builds on the remediation plan co-designed with Ngāi Tahu, guiding how legacy materials at the Tiwai site are removed, monitored, and recycled, and how the whenua is restored over time.”