The main underground working at Castle Rock has a cave-like entrance that leads down to an adit entrance. The adit is now flooded but is rock-cut and approximately 1.5m wide and 1m high at the entrance. Mining at Castle Rock (NPRN 33991) is not precisely dated but associated structures appear to be C19.
D Bick, The Old Metal Mines of Mid Wales, Part 4, 1977, pp 14-15.
Recorded as part of RCAHMW Uplands Initiative Project. R Hayman, H&H, 10/11/2011.