Rio Tinto's global chief executive flew to Wellington earlier this month to apologise to the Government for its handling of waste from the Tiwai Point aluminium smelter and make commitments around clean up.
Environment Minister David Parker today published a letter Rio Tinto chief executive Jakob Stausholm sent to Prime Minister Jacinda Ardern, which formalised the apology and spelled out clean up plans.
"We understand that we have to be better at listening to the communities in which we operate," Stausholm wrote in his letter to Ardern, dated Thursday.
"In New Zealand we did not do a good job of listening to our community regarding the Ouvea Premix waste, especially the material stored in Mataura and again I apologise for that. It did not belong to us, and we did not put it there, but it originally came from our operation and we should have done the right thing by removing the risk it presented to the community."
Early in 2020 hundreds of residents of Mataura in Southland were forced to evacuate amid fears that flooding would come into contact with the 9500 tonnes of ouvea premix from Tiwai which contractors had stored in the town's former paper mill.
Some of the waste remain in Mataura, although Stausholm's letter spelled out a plan for its removal, one of a series of clean up commitments including promises to remove waste from Tiwai Point and the results of testing of ground at the site.
This includes taking over the Crown's costs for removing the ouvea premix from Mataura, and later from other buildings in Southland, make other changes to its processes to reduce cyanide emissions from Tiwai Point and share ground samples with the Government, Ministry for the Environment and Ngaio Tahu.
"I will continue to closely monitor progress in New Zealand to ensure that we fully re-align the efforts and engagement to address your concerns," Stausholm wrote.
"I am committed to rebuilding an ongoing collaborative and positive working relationship with the New Zealand Government."
The Government welcomed the move.
"It has taken a long time to get to this point, but we welcome this commitment and the more conciliatory and open stance that NZAS has taken in recent months," Parker said in a statement.
"We also welcome the acknowledgment by NZAS of its responsibilities and how its environmental performance had disappointed the Government and the community of Southland."
"We appreciate Mr Stausholm's efforts to rebuild an ongoing collaborative and positive working relationship. With the smelter expected to close by the end of 2024, it is important to ensure these commitments are followed up by action to get the environmental outcomes for Southlanders and the region."
In a statement, a spokeswoman for Rio Tinto confirmed it would remove the material from around Southland and meet the cost of doing so.
"The material came from our operation and we will take responsibility for it, because it is the right thing to do," a spokeswoman said.
Ngai Tahu welcomed the news.
"Our local jobs and economy are dependent on our environment and environmental degradation would be a long term threat to employment and incomes in our region," Ngai Tahu spokesman Terry Nicholas said.
"We look forward to Rio Tinto keeping their word and delivering on what they have promised today."