The portal of Sir Francis Level is located on the west side of Gunnerside Gill, north of the village of Gunnerside in Swaledale, North Yorks.
The level was started in 1864 and was driven to reach the Frairfold Vein (Lead) which was achieved at a depth of 260 feet from surface in 1877. A shaft was sunk 1500 yards in from the portal to test the vein at depth and this shaft was equipped for winding and pumping with hydraulic engines, which still remain in place today.
The level has collapsed just inside the portal but access can be gained beyond the fall by descending the second airshaft, which requires a 25-foot ladder. Because of the fall at the portal, water in the level has backed up behind it and depending on the time of year is chest deep or deeper for much of the 1500 yards to the engines and winder. At the end of the level there is a junction, to the right is an unfinished connection to the Old Gang Mine which collapsed many years ago.
A short way to the left a flight of steps leads 12 feet up to the engine chamber and another short passage from the main level leads to the now flooded shaft containing two cages, one at the top and the other at the bottom below the water.
The engine chamber is in a remarkable state of preservation with its winding engine and water-pressure pump, designed by Henry Davy and installed in 1879. The water supply was from the Sun Hush Dam on the moor above. The pumps, designed to give a working pressure of 200 psi, could raise a load of two tons from 360 feet below level at 60 feet per minute and pump 500 gallons at six-and-a-half strokes a minute from the same depth (technical information from PDHMS bulletin). The mine was abandoned around 1890 when the sump had reached a depth of 120 feet.