Trans-Tasman Resources believes it now has an open pathway to getting consent to carry out seabed mining from offshore Pātea.
That comes despite the Supreme Court ruling the Environmental Protection Authority got it wrong when it granted consents to TTR in 2017.
It said the matter should go back to the Environmental Protection Authority (EPA) for fresh consideration - with one of the five justices saying the application could have been declined outright on the information provided.
But following the decision TTR executive chairman Alan Eggers said the company was confident it would now be able to get its consents.
"The legal issues are now very narrowly defined and there are no aspects of the judgment that are an impediment to TTR having the consents re-approved.
"The Court's rulings provide a pathway to a successful resumption of proceedings with the EPA."
In a statement Eggers pointed out the Supreme Court had said it would not be appropriate for TTR to be denied reconsideration for its application for the seabed mining consents.
The lengthy and complex judgment released on Thursday is the culmination of a court battle that began in 2017, when the EPA's decision-making committee narrowly gave consent to Trans-Tasman Resources' proposal to mine ironsand from 66 sq km of seabed offshore from Pātea in South Taranaki in water depths of 22m to 36m.
The decision was fought through the High and Appeal courts by fisheries interests, South Taranaki iwi and environmental groups.
The EPA declined the application the first time it was made. In 2017 the consents were gained only on the deciding vote of the committee's chairman.
The case concerns many points of law and will set a precedent.
The Supreme Court justices said if the seabed mining caused environmental damage, as it may from a sediment plume, decision-makers have to weigh up whether this could be avoided, reduced or remedied.
Economic considerations should be taken into account "only at the margins" or not at all.
The EPA committee failed to take the precautionary principle into account, the justices found.
And they took a "broad and generous" interpretation of the Treaty of Waitangi clauses in the Exclusive Economic Zone Act which governs activity offshore, saying tikanga should be taken into account as well as "other applicable law".
South Taranaki iwi Ngāti Ruanui and Ngā Rauru have spent seven years fighting the mining proposal.
Ngāti Ruanui "couldn't be more stoked" with the court decision, former kairarataki, and now Māori Party co-leader, Debbie Ngarewa-Packer said.
She is now calling on Government to ban seabed mining in Aotearoa and already has a bill to prohibit seabed mining in New Zealand in the ballot box.
The court's decision was very significant, Te Kaahui o Rauru tumu whakarae Mike Neho said.
"This is the first time that kaitiakitanga and tikanga have been tested at this level of law and this will be a game changer for recognition of iwi interests and decisions about the environment going forward."
TTR's Eggers has said in the past the mining proposal was an opportunity for a new $1 billion export industry.
He said it would have minimal impact on the environment and help meet the demand for the strategic metals, vanadium and titanium, required as the world moves to a low-carbon energy economy.