Mining company Trans-Tasman Resources has been sent back to the Environmental Protection Authority if it wants to make a third attempt to mine iron-sand from the South Taranaki seabed.

The Court of Appeal today dismissed TTR's appeal against a High Court judgment quashing its mining consents.

Groups opposed to the company's application welcomed the 290-page judgment but TTR spokesman Andrew Stewart said it was too soon for the company to comment.

"Any comments will be reserved until the decision has been properly considered in its entirety," he said.


South Taranaki iwi Nga Ruanui has opposed the application from the start, and kaiarataki Debbie Ngarewa-Packer said the win was thorough.

She doesn't believe TTR will make a third attempt to get consent from the Environmental Protection Authority (EPA), because it still can't say what effect the mining will have.

The EPA should never have accepted an application without full information about effects, she said.

"I hope [TTR] will take the loss and go away," she said.

Kiwis Against Seabed Mining (KASM) is calling for a ban on seabed mining.

Consents granted by the EPA have been thrown out on environmental and Treaty of Waitangi principles, chairwoman Cindy Baxter said.

The question of seabed mining is a major one for New Zealand. TTR and Chatham Rock Phosphate have been efused consent so far. The outcome of this case will set a precedent, Baxter said.

Trans-Tasman Resources wants to mine iron-sand in the South Taranaki Bight, 22-36km offshore from Patea. It wants to vacuum up 50 million tonnes of sand a year from a 66 sq km area, in water 20-50m deep.

Iron-sand would be processed in a vessel anchored offshore, in Trans-Tasman Resources' mining venture. Image / supplied
Iron-sand would be processed in a vessel anchored offshore, in Trans-Tasman Resources' mining venture. Image / supplied

The sand would be processed on a large vessel, and the 10 per cent that holds iron, titanium and vanadium would be exported to Asia. Remaining sand would be returned to the sea floor.

TTR has spent $80 million to get the venture this far. Executive chairman Alan Eggers said it would create about 1700 jobs, and increase New Zealand's GDP by $150 million a year. Its environmental effects would be negligible to minor, he said.

But opposition groups fear that mining and its sediment plume will harm birds, fish, marine mammals and other marine life.

The EPA approved the mining in August 2017, with 109 conditions. But the committee was split, and the decision made on the casting vote of the chairman.

Opposition groups of environmentalists, iwi and fishing interests appealed that decision to the High Court. In 2018 its Justice Peter Churchman upheld the groups' appeal, on the matter of "adaptive management" - permission to try the mining without knowing what effect it would have.

The consents were quashed and the decision sent back to the EPA. But TTR took the matter to the Appeal Court in September last year saying the EPA followed a legally correct approach in granting the consent and that the conditions were designed to protect the marine environment and existing interests, particularly iwi.