Not Wales, but just over the Severn bridge near Bristol. the lockdown has got me on my bike to keep fit. I've discovered 3 old mines down disused railways and dramways which I previously didn't know were there.
Brandy Bottom Colliery - well preserved (picture around 10 months old - it is now fenced off for an English Heritage restoration)
Parkfield Colliery - really just the chimney left
Ram Hill Colliery - wide gauge rail tracks remain, together with bases of buildings, but mostly gone
