Today is judgement day in the Federal Court of Australia for takayna / Tarkine and its Masked Owls threatened by mining company MMG’s proposed mine waste dump.

At a two-day hearing last week, our legal team asserted that former Environment Minister Ley did not take account of the precautionary principle when approving MMG’s destructive clearing and drilling. Our foundation told the Federal Court that Ms Ley’s decision to allow the mining company to undertake initial work at the proposed site was invalid as she did not properly consider the forest’s status as a feeding and breeding site for Tasmanian Masked Owls.

Tasmania’s Masked Owls are on the path to extinction. If allowed to proceed, MMG will cause serious and irreversible harm to ancient rainforests, melaleuca forests and habitat for rare and endangered species including the Tasmanian Masked Owls. The impact will be permanent and the landscape will be significantly altered.

The minister’s own EPBC act requires her to take account of the precautionary principle. In the case of MMG vs Masked Owls in takayna, the minister did not take the principle into account. The minister failed at the first hurdle.

Regarding the Masked Owl in these threatened forests, the minister claimed there was a lack of survey data by the company. She recognised more survey work was required.

In dealing with a species at high risk of extinction in the medium term, knowing that they’re there, not knowing how many are there, not knowing where they are by 25 references to the works, not knowing enough about the usage of the site, the delegate considered that protective measures were unnecessary despite her knowledge gaps. We say that this is further evidence of an approach that was not cautious and further evidence that whatever it was the delegate was doing – it cannot be described as taking account of the precautionary principle. A cautious approach required a very different conclusion. Kathleen Foley SC on behalf of Bob Brown Foundation.

Based on the evidence, or lack of, before the minister, we argued that her decision was unreasonable, irrational and illogical. The minister knew a species vulnerable to extinction is in this area, knew there’s habitat there, didn’t know how many owls there are or how they’re using the site and didn’t know where they are – and yet concluded it’s not likely to have significant impact.

Our foundation’s campaign scientists have carried out extensive research in these threatened forests for the breeding Tasmanian Masked Owls. They have proven there are breeding owls, that the forest is critical breeding habitat and that clearing for roads and drilling will cause serious and irreversible harm to the owls.

Today, the judge is announcing his decision, along with his reasons for reaching that decision. The undertakings that currently prevent MMG from clearing and drilling will remain in force until the judge makes a formal order dismissing the appeal. Next steps after the judgement today will be orders to resolve the case.

If we win today, it will prove the decision by Minister Ley was flawed, failing to account for the precautionary principle and will set aside that decision. This will compel the new Minister for Environment to make a new decision, which we argue should be to declare the proposed heavy metals tailings waste dump completely unacceptable.

If we lose, we will remain vigilant that Minister Plibersek’s reconsideration decision halts the destruction of takayna / Tarkine for this unnecessary proposal to dump 25 million cubic metres of mine waste into rainforests which are critical Masked Owl breeding habitat.

We have previously called for MMG to move to viable and accepted 21st century solutions like paste fill to dispose of its mine tailings instead of relying on dams, which have a long history of leaking acid.