Craig Ddu slate works (nprn 537337) was built in the 1880s and was water-powered for the first two decades of its existence. The wheelpit has walls of quarried slate blocks, but is part infiled with rubble, making its length and depth uncertain. It appears to measure approximately 7m long E-W by 1.2m wide, and can be measured to a depth of 1.5m. On its S side is a linear pit along which the drive shaft for the mill was housed.
Recorded as part of RCAHMW Uplands Initiative Project, R Hayman, H & H, 10/03/2014.