By Steffan Messenger
BBC Wales Environment Correspondent
Climate campaigners are taking legal action to try and force the closure of the UK’s largest opencast coalmine.
Planning permission at Ffos-y-Fran near Merthyr Tydfil ran out last September but the mine’s operators have kept digging for coal.
Campaigners want Merthyr Tydfil council and the Welsh government to take action to prevent further mining.
The Welsh government and Merthyr Tydfil council have been asked to comment.
Figures showed more than 300,000 tonnes of coal have been produced at Ffos-y-Fran since planning permission expired last September.
The operators – Merthyr (South Wales) Ltd – are in the process of appealing an enforcement notice from the local authority issued at the start of June.
The company has since been handed a separate notice from the UK Coal Authority after it was revealed mining was happening outside the permitted area.
Campaigners have said both Merthyr Tydfil council and the Welsh government have the power to go further and issue a “stop notice” to prevent further mining.
On Wednesday, lawyers on behalf of campaign groups Coal Action Network and the Good Law Project filed proceedings for a judicial review in the High Court.
They argued council officials and Welsh ministers have not acted quickly enough in their decision-making around what to do about the mine’s actions.
Coal Action Network campaigner Daniel Therkelsen said the council had “betrayed” residents and the Welsh government had “stubbornly refused to step in and put its climate policies into practice”.
Good Law Legal Manager Jennine Walker added it was “hard to believe” the company had been allowed to carry on mining “in broad daylight, for over 11 months” past the expiry of their planning permission.
Merthyr (South Wales) Ltd has been asked to respond.
In the past it has said “it would not be appropriate to comment whilst the appeal process is ongoing”.