Last week's High Court decision to overturn the consents issued to Trans-Tasman Resources to mine the seabed off Patea should have significant implications.

It means joy and vindication for a swathe of environmental groups and individuals who had opposed TTR's application and then appealed to the higher court. It means disappointment for the mining company.

It means a mixed bag for the people of South Taranaki whose concern for the oceans and the life therein may have been tempered by the prospect of jobs and an economic boost.

But the greater implications are surely for the Environmental Protection Authority whose four-person decision-making panel was split 2-2 on whether to approve TRR's application, leaving the chairman Alick Shaw to vote a second time, using his casting ballot to give the green light.

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The High Court judgment said the EPA decision was unlawful as it used an adaptive management approach. Adaptive management basically boils down to "go ahead and dig up the seabed for the next 35 years and if things start to go pear-shaped for the marine environment, please try and mitigate any damage".

Hardly a sound or considered way of going about things, as the judge rightly pointed out. But the nub of this matter goes back to that vote by the decision-making panel. The mining proposal was largely untried and untested, and at the application hearings even the experts agreed there were a lot of variables. There were models, estimates and guesstimates of what might happen, what the impact might be ... but nobody knew for sure. There were known unknowns and unknown unknowns.

Such was the uncertainty that half of the panel said the mining should not proceed. That should have been enough to stop it there and then; enough to err on the side of caution - TTR had not proved its case "beyond a reasonable doubt".

So Alick Shaw's decision to use his casting vote to give the go-ahead in the face of such concerns is bewildering and a little disturbing. There have been suggestions of "government capture" of some agencies, and the Ministry of Business, Innovation and Employment did support the application.

However, the judge made the point that the EPA must favour caution and environmental protection when information is uncertain or inadequate. The key word there is "caution".

Let us hope the judge's ruling is front and centre of the EPA's thinking the next time it faces one of these applications.