Fuelling the blacksmiths furnace: a multidisciplinary study into the use of ‘smithy’ coal in the iron-working industry of a late medieval harbour system, Bruges (Belgium)

Large amounts of iron slag were discovered during archaeological excavations in the late medieval harbour of Hoeke (Municipality of Damme, Belgium), one of the main outer harbours of Bruges. This waste product indicates the presence of 13th- to 14th-century pre-industrial metalworking activities, such as blacksmithing, which involved the production of iron objects and the repair of ships, as historically documented on this site. Besides the waste products from iron working, fragments of coal were also discovered within the same deposits, both as separate pieces and included in the slags, suggesting that coal was used as a fuel during these activities. This discovery resulted in a multidisciplinary study applying geochemical, palaeontological, and historical analyses that allowed to identify the provenance of the coal (Northumberland-Durham Coalfield) as well as to provide new insights into maritime coal trade during this period. This work contributes to a deeper understanding of pre-industrial craft practices in the Bruges harbour system and expands the knowledge of the fuel sources used in the late medieval harbour's iron-working activities.