The Coal Action Network has been granted a full judicial review into the UK and Welsh governments decision to approve the mining licence at Aberpergwm colliery.
In the latest developments over the controversial coal mine at Aberpergwm near Glynneath, the grassroots campaign group will submit its case to a senior judge before the High Court challenging the lawfulness of the coal mine expansion plans approved by Coal Authority.
The organisation argues the licence will see more than 40 million tonnes of coal mined at Aberpergwm by operator Energybuild Ltd.
In a statement to BusinessLive Wales, the Coal Action Network said: "Permission to proceed to a full judicial review in the High Court indicates we have a solid case and puts us an important step closer to reversing January's decision to licence a 42 million tonne expansion of the Aberpergwm coal mine.
"In a 1.5 day hearing in Cardiff, over the coming months, our crack legal team Richard Buxton Solicitors and Barrister Estelle Dehon QC, will challenge the parts that The Coal Authority and the Welsh Government played in this disastrous licence slipping through.
"The Government is dragging its heels putting its political spin into policy and practice - with the recent Climate Change Committee's report delivering a damning indictment. We must use all options open to us to fill the void of government inaction in ensuring a habitable world for future generations.
"If our case was seriously flawed or inconsistent, it would be weeded out at this stage by the judge looking over our application. Assigning 1.5 days to hear the case by a high court judge is a positive sign that our application presents a line of questioning that warrants an experienced examination.
"We're optimistic of course, but the outcome of judicial reviews are never certain and we remain in a David vs Goliath scenario, taking on the much more resourced legal teams and resources of both the Welsh Government and The Coal Authority."
In February, legal representatives for the Coal Action Network notified both the Coal Authority (hosted by BEIS of the UK Government) and the Welsh Government with a letter-before-action challenging the lawfulness of the decision.
The Coal Action Network and its legal team are challenging the granting of the application on the grounds that Section 26A of the Coal Industry Act 1994 clearly states that a licence only has effect if a Welsh minister notifies the authority that they approve the authorisation.
They also argue that the authority is not bound to approve the licence and could site climate change as a reason to withdraw the expanded licence and reject future coal mining applications.
There has been an on-going row for many months between Whitehall and Cardiff Bay over the mining licence as to which body has the authority to block the application which was approved on 27 January.
A spokesperson from the Coal Authority said it had previously engaged with the Welsh Government for any input it wanted to give on the application under the Wales Act 2017.
On 10 January, the Welsh Government told the Coal Authority that Ministers would not be making a determination on the case.
But, had Welsh ministers launched an objection to the licence, the Coal Authority said it would have been legally required not to issue the mining licence to Energybuild.
The Welsh Government rebuked the claim and said that, based on its legal advice, any determination it had made on the case would have had no legal status and resulted in a judicial review.
In an interview with BusinessLive Wales, Energybuild said that it is trying to pivot the business to become less carbon intensive as it phases out hydrocarbon production and turns to non-thermal industries.
These include supplying high-grade anthracite (hard coal) for recycling lead out of batteries and water purification in carbon filtration systems.
There is no date yet as to when the judicial review will take place and the Coal Action Network may not get a final decision until 2023.
The campaign group is now raising funds to pay the legal costs to challenge the Welsh Government and Coal Authority. It has so far raised £17,282 of its £65,000 target through its crowdfunding page.
