During improvement works on the N11 in County Wicklow, a shallow pit was uncovered at Coolbeg that pointed quietly to earlier industrial activity in the area. Irregular and oval in shape, measuring roughly 2.8 metres along its longest axis and just under 40 centimetres deep, it was not a dramatic find by any measure, but what it held was telling.

Archaeologist Goorik Dehaene excavated the pit as part of the N11 road improvement scheme, recording it under the reference E3251. The fills inside contained two materials that, taken together, suggest some form of metalworking: charcoal, which would have fuelled a fire to reach the high temperatures iron requires, and iron slag, the glassy waste produced when iron ore is smelted or worked. Slag is one of the more durable traces of early industry, surviving in the ground long after the structures and people associated with it have vanished entirely. The pit itself may have served as a working hollow, a dump for waste, or something connected to a hearth or furnace nearby. Without a wider excavated context, its precise function remains open.