In the wake of the Paris Agreement, pressure has intensified on the Australian government to reject Adani’s proposed Carmichael mine, which will be one of the biggest mines in the world.

In order to stay below 2℃, scientists have estimated that more than 90% of known coal reserves in Australia must stay in the ground. Depending on the economics of various coal reserves, this may mean the Galilee Basin is “unburnable coal”.

Yet, this mine has already been approved by the federal environment minister Greg Hunt, and on Tuesday Queensland’s Land Court also recommended approval of the mine.

At a federal level the mine has been approved, had its approval set aside, and then been re-approved. There is a final Federal Court challenge to be heard in 2016.

But is it even possible for the Australian government to reject the Carmichael coal mine? Or have we already gone too far down the path of approval?

Broadly speaking, there are three key approvals needed by a proponent to conduct a large mining operation in Queensland: a mining lease, issued by Queensland’s minister for natural resources and mines; an environmental authority, issued by Queensland’s Department of environment and heritage protection; and an approval under the Environment Protection and Biodiversity Conservation (EPBC) Act, issued by the federal environment minister.

The Queensland approval process

Queensland’s approval process is somewhat unusual, in that there is a preliminary decision on whether to approve, followed by an opportunity for any objections to be heard by the Land Court. The Land Court then makes a recommendation to the ministers, and a final decision is made.

The Queensland government recommended approval for the Carmichael Mine in May 2014. Land Services of Coast and Country objected to this, on grounds including potential climate change impacts, and impacts on endangered species.

Following a five-week hearing earlier this year, the Land Court yesterday recommended that the Carmichael Mine be approved, subject to additional conditions.

The Land Court recommendation is not binding on government; under the respective Acts, the Environment Minister must “have regard to” the recommendation, and the Mines Minister must “consider” it.

The federal approval process

Under the federal approval process, the federal environment minister may approve an action. This decision may be judicially reviewed, and the EPBC Act grants standing to environment groups active within the previous two years.

Environment minister Greg Hunt initially approved the Carmichael mine on 24 July 2014. This approval was challenged by the Mackay Conservation Group in the Federal Court.

The approval was set aside on 4 August 2015 when it was found that Minister Hunt had failed to consider the relevant conservation advice for the yakka skink and ornamental snake.

It was this decision that sparked the so-called “lawfare” controversy, with Federal Attorney-General George Brandis announcing a plan to remove the section of the EPBC Act granting standing to environment groups.

Following the Federal Court order, Minister Hunt then considered the relevant conservation advices, and issued a new approval for the project on 14 October 2015.

A fresh application for judicial review has been made by the Australian Conservation Foundation, challenging the Minister’s consideration of the impacts of the project on the Great Barrier Reef, and an endangered species. This case will be heard in early 2016.

Can this mine be stopped?

At the state level, final approvals have not yet been given. There is consequently an opportunity for Queensland’s ministers to reject the proposal. There is no legal precedent for this, as historically mining projects have always been permitted, although subject to conditions. It is unlikely any legal challenge could arise from a refusal at this stage, as no legal right has yet been granted.

At the federal level, there has been a final decision by the Minister, although that is subject to review by the Federal Court. If the Federal Court challenge fails, the only option would be for Minister Hunt to revoke the approval.

The EPBC Act specifies circumstances when an approval may be revoked, including when new information emerges, or if information was withheld by the proponent. The Minister may also consider the environmental history of the proponent. It is not clear whether these circumstances are exhaustive, although the Federal Court has indicated they are not.

Regardless, Minister Hunt may arguably have the new information needed to squarely enliven this power anyway. The Queensland Land Court proceedings brought to light new information regarding the habitat of the endangered black-throated finch, which may not have been available to Minister Hunt at the time of assessment.

Additionally, new information has emerged in recent weeks regarding Adani’s environmental history.

Finally, the Federal Court proceedings in 2016, even if unsuccessful, may reveal new information about the project. These circumstances all suggest that the door is not firmly closed to Minister Hunt revoking Adani’s approval.

Again, there is little precedent for this course of action. Of the 5,364 applications made in the history of the EPBC Act, only 20 have been rejected by the environment minister. There is even less precedent for a project being approved, and then rejected afterwards.

Saying “no” to the Carmichael mine would undeniably be controversial, and a significant departure from Australia’s historical reluctance to reject mining proposals.

Regardless, the legal power does exist for Australian governments to act, both at the federal and state levels, to prevent a project that could be at odds with the renewed global commitment to tackle climate change.