Nantymwyn Mine is an upland lead mine located about one kilometre north of Rhandirmwyn, straddling the ridge of Pen Cerrig-mwyn. In addition to shafts, adits and spoil heaps, recorded remains typical of seventeenth to nineteenth century mining include mortar stones, hand cobbing and crushing floors, opencasts and pre-gunpowder workings.

A series of small, shallow and primitive overhang excavations cut into the south side of the ridge may have been random prospections excavated by means of firesetting, believed to be of possible medieval date. Hush gutters were recorded on both east and west sides of Pen Cerrig. Radiocarbon dates from silted channels have been taken to imply a Roman date for hushing leats. The mine was last worked in the 1930s and there are surviving remains of opencasts, buildings and dressing floors.

Claire Parry, RCAHMW, 13 June 2011.

Source: Association for Industrial Archaeology: A Guide to the Industrial Archaeology of Mid-Wales, 1984