What made the find unusual was not its scale but its specificity: the pit contained almost nothing but the carefully categorised waste of a blacksmith's workshop, preserved in layered fills that told a legible story about how the feature had been used and eventually abandoned.

The excavation was carried out in December 2018 by archaeologist Yvonne Whitty, working within the designated constraint area for Baltinglass Historic Town. The pit, designated feature C23, was sub-rectangular in plan, aligned northeast to southwest, and measured 3.9 metres in length by 2.2 metres in width. Its primary fill was a black sandy silt packed with smithing hearth cakes, the dense disc-shaped slag that forms at the base of a blacksmith's hearth during ironworking and is periodically broken out and discarded. Individual examples weighed between 262g and 1,386g. Alongside the hearth cakes were fragments of clay tuyeres, the ceramic tubes through which bellows-driven air was directed into a forge to raise its temperature. The largest surviving tuyere fragment, weighing 266g, came from the front of a truncated cone-shaped pipe and still had a so-called slag beard attached, a vitrified crust that builds up where the tuyere meets the most intense heat. Analysis by specialist Rondolez confirmed that the material represents secondary blacksmithing, meaning the smith was working with already-smelted iron rather than producing it from ore, most likely forging large objects or high volumes of smaller ones. Crucially, the actual smithing did not happen in or near the pit; the waste was collected elsewhere and dumped here. Above the primary fill, successive layers of redeposited natural soil and siltation gradually sealed the deposit as the pit fell out of use. The assemblage is dated to either the early or late medieval period, a bracket that leaves open the question of whether this was the work of a smith operating in an early Christian settlement context or in the more organised commercial environment of a later medieval town.