I've abseiled into a stope near south shaft, it looked fine to me. I've also seen other access points. I gather the ground is good. The thing is, do you really want to see a massive stope with simple, well defined walls, with business like timbering....?
It's basically pretty boring really, as mines go. No secondary minerals, no artifacts, it's just a bloody great big slot in a hill.
Great Royalton mine is far more interesting.....