At the base of an east-facing rock cliff in County Waterford, cut into the stone beside the Curraghteskin stream, there is a small L-shaped cave that measures only about three and a half metres in total length. Its opening is just wide enough and tall enough for a person to enter with care. It is entirely man-made, and it is classified as a mine, though its purpose and origins remain unrecorded. Two modern drill-holes in the back wall are the only clear indication of comparatively recent human activity inside it.

The site sits on the western bank of the Curraghteskin stream, which runs roughly south to north through the Knockatrellane area. Beyond its physical description, very little is documented about this particular cutting. The term "mine" in an archaeological context does not necessarily imply industrial-scale extraction; small trial adits, as exploratory cuttings are known, were sometimes driven into cliff faces to test for mineral veins, and many were abandoned after only a short investigation. Whether that is what happened here is unknown. The drill-holes in the back wall suggest that at some point someone intended to go further, but no record of what, if anything, was found has survived.