Charcoal-making pits of this kind were essentially controlled burning chambers, dug into the earth to smoulder wood slowly and drive off moisture and volatile compounds, leaving behind the dense, high-carbon fuel needed for metalworking and other heat-intensive crafts. The site at Hardwood, designated Hardwood 2 during pre-motorway investigations, preserved five such features, each slightly different in shape, cut into the subsoil and surrounded by oxidised, heat-reddened clay.

The features came to light during centre-line testing carried out by archaeologist Ian Russell in 2002, as part of the standard archaeological assessment required ahead of motorway construction. Subsequent excavation revealed a trapezoidal pit measuring roughly 1.7 metres by up to 1.5 metres, a circular one around 1.45 metres in diameter, and three rectangular pits ranging from approximately 1.8 to 2.4 metres in length. None were especially deep, the shallowest barely 0.1 metres, the deepest 0.25 metres, but all contained substantial charcoal deposits. A radiocarbon date obtained from a charcoal sample placed activity at the site somewhere between around AD 1020 and 1210, a period spanning the late early medieval era into the early decades of Anglo-Norman settlement in Ireland. Beyond a single stray piece of flint, no other finds were recovered, and the precise context for the dated sample was not recorded, leaving the broader picture of who worked here and why somewhat open.