What the subsequent excavations revealed was small but genuinely significant: a burnt pit measuring roughly 65 centimetres by 117 centimetres, and just 18 centimetres deep, containing the base of a shaft furnace. A shaft furnace is a vertical structure into which ore and fuel are loaded from the top, with air forced in from below to sustain the intense heat needed to smelt metal. Finding even the lowest portion of one intact is relatively uncommon, since these structures were typically dismantled or simply eroded away once they fell out of use.

A radiocarbon date obtained from material within one of the pit's fills placed the furnace firmly in the medieval period, somewhere between AD 1270 and 1390. Fragments of charcoal recovered from the same fills almost certainly represent fuel residue from the smelting process itself. The furnace did not exist in isolation. A linear feature lay directly to its north-east, and both this feature and the pit had been cut into a U-shaped fosse, a type of defensive or boundary ditch, aligned roughly north-east to south-west and measuring nearly six metres in length. The relationship between the furnace and the fosse is not entirely clear, but the fact that the furnace cuts into the ditch suggests the industrial activity came after whatever boundary or enclosure the fosse had once defined. It is a small, layered sequence of activity, compressed into a modest patch of ground in county Kerry, and it would almost certainly have been lost entirely had the ground not been examined before the builders moved in.