Ancient Fluorite Mine
I managed to make it about a mile and a half in with no end in site...
This Derbyshire mine was originally driven as a sough to the workings under Longstone Edge, before being modified into a haulage level in 1840-42. A 32ft diameter waterwheel originally powered crushing rollers here, but all traces of it have been destroyed by later workings. In the 20th century, the Mine was used to mine for fluorspar, first from 1926-30, and then from 1965.