Nent force
"During the area's peak of prosperity in 1776 John Smeaton began construction of an underground drain to assist with the transport of extracted materials as well as locate new mineral seams. The canal took 66 years to construct at a cost of £80,000, and became known as "Smeaton's Folly". In the 1830s mine manager and engineer said that it could be visited "in boats 30 feet in length, which are propelled in four feet of water by means of sticks projecting from the sides of the level; and thus may be enjoyed the singular novelty of sailing a few miles underground". It was intended to be 9 feet square but in the softer terrain was extended to 9'x16', dead level for 3.75 miles (6 km) to allow boat use, with a rise of 35 fathoms (64 m) at Lovelady Shield and then driven into the Nenthead ground. The amount of ore found was disappointing, though not insignificant.
Access to the Nent force level is currently extremely difficult although efforts have been made to develop a heritage centre to make this extraordinary piece of engineering accessible to the public"
Found this and thought it might be interesting to some.
Some pics here.
http://www.mineexplorer.org.uk/breweryshaf...5.htm#position3