Forming part of the Ystrad Einion Metal Mine (NPRN 33908), this underground waterwheel operated drainage pumps to the lower levels of the mine and also powered a winding drum for bringing ore to a higher level of the mine, prior to its transfer aboveground via the main shaft. The wheels dates to the 1870s during a period when the mine was laid out anew by new owner Adam Mason.

The waterwheel stands, in a large rock cut chamber (a former stope) and is supported on a wooden frame wedged to the sides of the chamber. It is 4.8m in diameter, with a cast iron rim and hub with wooden spokes and buckets. On the end of wheels axle is a crank shaft, and a small pinion. The crank shaft operated a pump by means of a chain which ran over a series of guide pulleys (dolly wheels) before being attached to the pump rods in the pump tube of a shaft. To balance it there is a small wooden balance bob and wight box, attached to the other side of the crank by an iron rod. Slightly below the crank shaft, and formerly driven by a pinion, is a spur wheel 2.08m in diameter, with a flat web and two pins on the end of the shaft. This would have driven the winding drum by some form of clutch pulley, now removed. The drum 1.2m in diameter was originally mounted on a wooden frame, it has a cast-iron frame and cast iron brake rim, with wooden slating to the winding surface and an iron band brake. The shaft that this wheel pumped and drew from is now flooded, it is situated 15m away. The water supply to the wheel was delivered from the mines main leat and ran underground along a launder and feed the wheel from above; the wheel turned anti-clockwise.

Louise Barker, RCAHMW, Jan 2012