Fears opencast mine could become dangerous lake

Merthyr Tydfil's Ffos-y-Fran mine was responsible for 86% of the UK's total coal output before it closed

Residents who live near the UK's largest opencast mine have "grave concerns" over rising water levels at the site.

Work at Ffos-y-Fran stopped in November 2023, and emails shared with BBC Wales show Merthyr Tydfil council believes a revised restoration proposal will include a body of water.

Campaigners fear the community will be left with a "dangerous" and "contaminated" lake if the giant pit is not filled in as was originally planned.

The mine's operator - Merthyr (South Wales) Limited - said ground water levels were being continually monitored as it worked on updated plans for the site's restoration.

The mine was responsible for 86% of the UK's total coal output before it closed.

Chris and Alyson Austin live opposite, and said residents had been "absolutely shocked" by drone footage of rising water levels in recent months.

"It's filling very rapidly with the weather we've been experiencing and it won't be long before it gets past the point of being able to do anything about it," Mr Austin, 68, said.

Mrs Austin, 60, added that opencast coalmining had been "forced" on the local community as a way of paying for derelict land to be restored.

"We've now been left with a situation that's far more dangerous than we ever had before," she said.

"Never mind whether the site is watertight or if toxins could leach, if a child falls in there they'll never get out."

As a restoration is discussed, the site looks very different to how it did a year ago

The couple emailed Merthyr Tydfil council, who replied to say it was "very much alive" to the concerns they had raised.

The council said there were currently no plans for the mine's operator to "reintroduce pumps on site to remove the water from the mining void".

A planning application for a revised restoration scheme was expected in late autumn 2024, the email said.

This new plan was "likely to include the retention of the water body within the mining void" with the surrounding land being "appropriately re-profiled".

The couple said they had been shocked by the response and had "grave concerns".

"It's awful - they're just sitting back and watching it unfold," Mr Austin said.

"We will be left with a dangerous structure for the future of Merthyr there in perpetuity."

Now the opencast has closed, local people are worried about what will happen

Ffos-y-Fran is officially classed as a "land reclamation scheme", meaning the vast site close to homes and businesses in Merthyr Tydfil was to be restored to green hillside for the community's benefit.

Spoil heaps built up as more than 11 million tonnes of coal which was extracted over 15 years were to be pushed back into the mining void, which is 656ft (200m) deep in places.

But recently Merthyr (South Wales) Limited warned of "insufficient funds" set aside to carry out the work as planned and an alternative proposal was needed.

In November 2023, 115 staff were made redundant as coal mining stopped, more than a year after the site's planning permission had run out.

The Ffos-y-Fran mine is about the size of about 400 football pitches

The chief executive of the UK Coal Authority Lisa Pinney wrote to the Welsh government at the time, criticising the local council's grip on the situation.

The letter was shared with BBC Wales after being obtained by campaigners at the Coal Action Network via a freedom of information request.

Ms Pinney had warned in October 2023 there was "no robust plan for the site's closure" and "no understanding of how rising water levels would be managed".

Delyth Jewell, the Plaid Cymru Senedd member for South Wales East, said the situation at Ffos-y-Fran was being "allowed to get worse all the time".

"All public authorities seem to be washing their hands of this," she said.

"We need to get this (site) surveyed urgently, we need to get those pumps working again, and we need to make sure it is restored adequately as the residents of Merthyr Tydfil were promised in 2007."

Ms Jewell, who is also the party's spokesperson on climate change, said she had written to the Welsh government asking for it to intervene.

"If necessary we need to have a compulsory purchase of that land," she said.

"Our coal is ripped from the earth and we have a void that is left for the community - a void that is now filling with water," Delyth Jewell said

A spokesman for Merthyr (South Wales) Limited said ground water levels had been monitored on a regular basis since mining had stopped in November, "under the guidance of a consultant hydrogeologist".

"Following one of the wettest winters on record ground water levels have stabilised around the levels monitored prior to commencing mining operations," he said.

They were currently "some 200 feet" below the lowest natural ground level at the site, he added.

"Water levels will be continually monitored throughout the restoration phase to ensure they remain within the parameters of naturally occurring ground water levels," the spokesman said.

The Coal Authority said managing the restoration and associated public safety was "a matter for the landowner and local authority" but that it would continue to provide advice as needed.

A spokeswoman for the Welsh government said it was closely monitoring the situation at Ffos-y-Fran and "our priority is the safety of the local community".

“We have been clear that the safeguarding of the site is our main objective and that we expect to see a full restoration in line with planning permission," she said.

Merthyr Tydfil council said it continued to work with the company "to agree interim restoration works prior to the submission of a future revised restoration strategy".