During 2015, OA East was commissioned by Andrew Josephs Associates to excavate a potentially very early iron smelting furnace in advance of an extension of the Sibelco Ltd sand extraction quarry at Messingham, Lincolnshire. Radiocarbon dates obtained from an earlier evaluation suggested that the furnace originated in the late Bronze Age/early Iron Age, although some doubt had been cast on the validity of this date.

Despite freezing winter weather, the OA East team carefully exposed, excavated and recorded the furnace and associated slag heap; a second mound was also excavated during a later stage. Preliminary assessment of the iron-working slag has been carried out by the project archaeometallurgist, Gerry McDonnell. The charcoal assemblage recovered has also undergone initial assessment at OA East's environmental facility.

A major result of this work is that a sample of charcoal taken from within the furnace wall that was sent for radiocarbon dating returned a date of 776-509 cal. BC at 95.1% confidence (SUERC-59289), which largely confirms the previous results. Combined, these provide a clear early Iron Age date range of 776-590 BC, making this – as far as the archaeometallurgist or we can ascertain – the earliest dated smelting furnace in the country. The full analysis of the slag assemblage will make a valuable contribution to current understanding of the industry and economy of the early Iron Age in Britain.