Coal tips: Cost of securing them could cost £500m
More than half a billion pounds could be needed to ensure the safety of 2,000 old coal tips in Wales over the next 10 years, the chancellor has been warned.
It follows calls for urgent action, following a 60,000 tonne landslide earlier this year at Tylorstown, Rhondda.
That came after heavy rain caused by Storm Dennis, which led to widespread flooding.
Ben Curtis, a historian of the south Wales coalfields at Wolverhampton University, said: "Just struck by the scale of the landslip. It's really quite awe inspiring and not in a good way.