Would this be Croes y Ddwy Afon, on the Mignaint?
Ahah! Give that man a biscuit!
SimonRL has been there:
🔗Croes-y-Ddwy-Afon-Slate-Mine-User-Album-Image-001[linkphoto]Croes-y-Ddwy-Afon-Slate-Mine-User-Album-Image-001[/linkphoto][/link]
The underground side of it looks rather grubby!
Ah yes, that's definitely Croes y Ddwy Afon.
Underground there's one filthy ocherous tunnel (unusually so for slate) and some collapsed chambering containing a reasonably well preserved air receiver.
On the other side of the pit is a fenced off, and clearly fiercely dangerous, boulder. I've never seen a boulder get up and run off, so presumably the fence isn't keeping it in.... There appeared to be a squeezable gap by the boulder, so perhaps it's possible to gain access to more chambers that way?
my orders are to sit here and watch the world go by