I thought the first evening trip was called Cabin Shaft...however I am not so sure now, It defo was not Hendre. It was about 45mins from Snowdonia, there was a largish gravel area for parking (size of a football pitch or so) with some old mine outbuildings near by. It was in a designated conservation/walking area. The mine was a short SRT in (tie off on a tree then a 10m pitch) then about a 1.5 hour trip. There were a few SRT pitches, the last one, was more of a 45deg traverse up. Passage was small and cave like, with stacks of rubble propped up on old wooden beams that need to be navigated in close proximity. I would put/est the mines age at around 1900