The last operating opencast mine in the UK, which produces around two-thirds of the country's coal, has closed amid concerns that it could be left abandoned.

The Ffos-y-Fran pit in Merthyr Tydfil has produced nearly 11.25 million tonnes of coal since opening in 2008, and is responsible for 86% of the UK's total coal output.

The mine is now set to close, with more than 100 job losses, after Merthyr Tydfil County Borough Council refused an application in April from its operator Merthyr (South Wales) to extend its operational life to next March.

Earlier this year, First Minister Mark Drakeford said: "While it is the clear policy of the Welsh Government that finite fossil resources should stay in the ground, in that transition away from coal mining we still have to pay proper attention to the fates of individuals whose livelihoods are still bound up in it."

Estimated clean-up costs for the site, which is 656ft (200m) deep and the size of 400 football pitches, are thought to have grown to between £120m and £175m.

Campaigners say they are concerned the site will be left abandoned, with dire environmental consequences.

The site operator has said it "committed" to restoring the site in future and would not walk away.