It is not a relic of industry in any grand sense; it is, quite possibly, a piece of military improvisation from one of the most turbulent episodes in the city's history. A single musket ball recovered from the backfill connects the pit to the Cromwellian siege of Kilkenny, fought in the spring of 1650.

The furnace was identified during test excavations carried out by archaeologist Paul Stevens, and its position tells a particular story about the urban landscape of seventeenth-century Kilkenny. The site sits roughly twenty metres north-west of the former St James's Gate, one of the entry points through the medieval town wall of the Hightown. The furnace itself was oval in plan, about three metres across and just over half a metre deep, with a linear flue extending from one side. It was lined with boulders and showed intermittent layers of burnt soil and silty clay, the signature of repeated firing. The fill was dense with iron slag, the residue left after metal is smelted, suggesting the structure was used to work iron, perhaps to cast shot or repair weapons during the siege. The furnace had been dug into an older medieval rubbish pit, which is its own small reminder that the ground here has been disturbed and reused across many centuries. The same plot also yielded a medieval well and a burial, suggesting that this corner of Kilkenny has rarely sat undisturbed for long.