Not a ruin precisely, not a monument, simply a shaft that was quietly swallowed by the promenade when it was built, absorbed into the base of a shelter on the city side of the swimming baths and largely forgotten.

The mine itself has a surprisingly long paper trail. A lead mine on the shore at Clontarf appeared in a list of mines drawn up in 1497, and according to the historian De Courcy, it remained in production for roughly three hundred years after that first mention. Lead mining in Ireland during this period was typically small in scale, extracting galena ore for use in everything from roofing and piping to the manufacture of shot and paint pigments. By the time the Ordnance Survey was mapping the area in 1837, the mine had already ceased working, but the cartographers still thought it worth recording, marking the spot as 'Pump and Site of Old Lead Mine' on the six-inch edition. That label alone suggests something was still visible at the time, some pump machinery or surface feature that made the location legible to surveyors even in its disused state.

There is no formal marker or interpretive sign at the site today, and the shaft is not accessible. The shelter on the Clontarf promenade, on the city side of the baths, sits over it without any particular announcement of the fact. Walking the promenade, it is easy to pass the spot without a second glance. The interest is almost entirely in the knowledge rather than anything visible. If you are walking east along the seafront and stop at the shelter, you are standing, more or less, over a place where men were extracting lead ore as far back as the late fifteenth century, in what is now one of the more leisurely stretches of the Dublin coastline.