Got your PM, but no secrets there.
All the mines have lift gates but no locks.
There are no sexy dives, most mineralisation was in a single strata, the Great Limestone, and it was worked by long horse levels driven under the fells. There was also some in the Little LM and other strata, this plus some heaving lead to levels being driven on other horizons. All the workings in the Upper Nent valley interconnect.
So dont expect flooded sumps (winzes) with locos at the bottom!
Download this and have a good read, its still possibly the best guide to the area.
https://pdmhs.co.uk/MiningHistory/Bulletin%209-1%20-%20The%20History%20and%20Workings%20of%20the%20Nenthead%20Mines,%20Cumbria.pdf If you do get to miss deep water you can do the Caplecleugh to Smallcleugh through trip, my "Fish Trip", you wont need air bottles, its just that some of it might look at though you do.
A lot of the info is on here.
Thinking about it, there is something that your specialist equipment could work for, PM on the way.
My avatar is a poor likeness.