The facility will process spent cell liner (SCL), a by-product of the aluminium production process. Historically SCL been stored undercover in sheds, and in a specially designed pad on-site.
In 2021 then-Rio Tinto global chief executive Jakob Stausholm flew to Wellington to apologise to the government over its handling of waste from the smelter, and made commitments around the clean-up.
That came after hundreds of residents of Mataura were forced to evacuate early in 2020, amid fears that flooding would come into contact with the 9500 tonnes of ouvea premix from Tiwai Point, which contractors had stored in the town’s former paper mill.
Since January 2024, NZAS has worked with specialist processor Regain to safely treat SCL in Australia, before it is 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,” said Rio Tinto NZAS acting general manager Matt Black.
Mr Black said SCL previously stored in the encapsulated pad will be progressively excavated, processed on-site and exported for re-use.
The project will create 20 jobs during construction and six during operations.
All consents for the facility have been received, and construction is expected to begin in the second quarter of next year. Once operational, the plant will be run by Regain Services Ltd, which also operates a similar facility at the Tomago smelter in New South Wales.
“Processing SCL on-site is a milestone in delivering on the remediation commitments we have made to Ngāi Tahu and our community,” Mr 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.
“Our partnership with mana whenua is central to how we operate at Tiwai,” Black said.
Rio Tinto managing director of Pacific operations Armando Torres said it reflected the commitment to the remediation programme.
“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 the investment was “another positive step forward in the remediation of the Tiwai site”.
The remediation programme has already seen more than 36,000 tonnes of SCL exported for reuse since 2024, alongside major progress in returning ouvea premix and processing historic dross.
– Allied Media
