It was modest in scale, barely three-quarters of a metre across and less than twenty centimetres deep, yet the grey and black clay that filled it, laced with charcoal and traces of slag, tells a quietly specific story about early medieval industry in the Irish midlands.

The site came to light during archaeological testing carried out ahead of the M4 motorway between Kinnegad and Kilcock. Excavation in August 2002, conducted under licence by R. O'Hara, uncovered what is described as a bowl furnace, a simple pit-based smelting or metalworking feature in which fuel and ore are packed together and fired to produce workable metal. The furnace bottom showed oxidised, heat-reddened sides, and radiocarbon dating of the charcoal within it returned a calibrated date range of approximately AD 890 to 1150, placing it somewhere in the later Viking Age or early Norman period in Ireland. A nearby oval pit, slightly larger at just over a metre in length, contained a substantial quantity of slag, the glassy residue left over from smelting. Several other shallow cuts with scorched bases are read as the remnants of hearths, one of which produced a comparable date of cal. AD 980 to 1170. The picture that emerges is of a working area used repeatedly over a span of time, rather than a single episode of activity. A kiln, a separate structure recorded independently, lies approximately eighty metres to the west, suggesting this was one part of a broader cluster of early industrial and agricultural features spread across the same undulating ground.