I fell doubly sad about this as I seemed to have completely missed the import of this thread until today and I live 3 miles from Nailsworth and would have liked to have at least been involved with the Stroud Valleys Group and their tour. Access to the mines is a closely guarded secret and official access is a bit of a red-letter day and knowing the right people counts. Balls Green had some interesting artefacts including, I believe 2 cranes and I understood that the collapse destroyed one of them. I was told that the mine was very unstable, but not unstable enough to prevent a party of 12+ entering, apparently. Isn't it interesting that despite all the secrecy and hoo-ha, Buffalo Bill was allowed in with his cutter.