Opencast mine developers have repeatedly “cut and run”, breaking promises on restoration and costing taxpayers hundreds of millions of pounds, a Senedd committee warned.

Llŷr Gruffydd, climate change committee chair, led a debate on a report following an inquiry on the restoration of opencast mining sites.

He told the Senedd: “In all of the cases that we looked at, the restoration work has fallen woefully short of what was promised.

“We have seen companies – sometimes the same company – repeatedly cut and run without keeping to their end of the bargain. Restoration failures have meant losses to the public purse amounting to hundreds of millions of pounds.”

Mr Gruffydd raised concerns about a “clear lack of accountability” from site operators and public authorities, with those involved “refusing to take responsibility” when things go wrong.

The Plaid Cymru politician visited Ffos y Fran, the UK’s last opencast mine in Merthyr Tydfil which closed in 2023, alongside fellow committee members last week.

He said people living nearby have been proved right, with restoration plans revised.

Mr Gruffydd welcomed the Welsh Government’s confirmation that new coal extraction should only be approved under “wholly exceptional circumstances”.

He also welcomed £25m from the UK budget for coal tip remediation in Wales, saying: “It is unlikely to be sufficient, as we all know, but it is a start.”

Plaid Cymru's Delyth Jewell described Ffos y Fran as a debacle as she raised concerns about broken promises and environmental scars.

Ms Jewell, who represents South Wales East, warned history could be repeated due to a loophole, pointing to plans involving “coal extraction almost by stealth” at Bedwas.

She argued Westminster should pay in full for coal tip reclamation, saying it will come at the expense of the environment if left to private companies.

Rhianon Passmore, Islwyn MS, raised concerns about 10 lorries an hour potentially going through the Sirhowy country park.

Responding to the debate on November 13, Huw Irranca-Davies outlined the Welsh Government’s formal response to the committee’s recommendations.

Mr Irranca-Davies, deputy first minister, told the Senedd that a disused mine and quarry tips bill will be introduced before Christmas.