A one time only break from my posting hiatus, this is brilliant and has had me on the maps on Rotherham, Yorkshire really delivers! Let’s hope some of you York’s based explorers pit yourselves together and crack more of these places!
I would be a bit wary in there myself, seems like it is a place that could kick into gear at any time, and being in that chamber before you went through the flap could be a scary one, unless someone knows more? Either way, interesting and loved the pics