Whilst scrubbing around in the undergrowth I found an Adit entrance in Cressbrook Dale - Derbyshire. The undergrowth was to dense to get a good photograph, it's location is about 100 meters from the Neptune Mine (lower) entrance, on the other side of the dale, there is a grill over the entrance (vertical bars) that appear to be broken on one side (I didn't venture to close as there appeared to be a pit on the entrance run-in), anybody have any background knowledge.
Can supply Grid coordinates on request