The CDG Peak District Sump Index Update 1997 says, of Watergrove Mine, that extensive pumping was necessary to work the mines. However in the 1974 drought the pumps pulled air. Doug Nash was in an Op Mole party which forced the rarely unwatered passages. He was back there in the 1976 drought, pushing a low airspace section along the sough - but turned back when his pipe went out!
I remember sitting in Glebe Cottage listening to Doug describing these trips and in particular how clay was being squeezed out from cracks in the walls like toothpaste, due to the rock moving as it was no longer being supported by the water. Scary!
None of the above really helps answer the OP's question but perhaps it serves as an example to give some idea of the amazing stuff which Operation Mole members got involved with.