It's hard to believe now, but a century ago this area was full of industry - this multi will help you explore a little bit of it. If you park in the nature reserve's main car park, you can actually walk to Birley East along the old railway line, which is now part of the Trans Pennine Trail network. The trail is up a few steps opposite the entrance to the car park.
Despite knowing the valley pretty well, a couple of years ago I came across a new location and thought it would be ideal for a cache. However there was already a cache nearby, that just so happened to have been the first ever geocache I found (GC69ZR1), so it wasn't possible. That one has now been archived, so I can place my cache.
At the waypoint you'll find two dates ABCD - EFGH. The final cache can be found at N53 21.E(B+A)A, W001 21.FC(H-E).
It is possible to get to the final GZ quite easily - but not in a straight line!