Metal slag, summarised from specialist report by Phil Andrews
A tiny assemblage of metal slag was retained from the Glastonbury Abbey excavations. The copper alloy debris (mostly slag) was probably from the casting of copper alloy, with several fragments of copper/bronze ingot/s possibly representing the raw material. Most of the material with a context was from the east and west cloister walks and the most likely source of the copper alloy debris is in relation to bell-founding. Analysis of the fragments may establish that these are bronze rather than copper and thus likely to be 'bell metal' ready for casting.
Iron working debris was also present; although undiagnostic the nature of the debris indicates iron smithing with one piece comprising a hearth/furnace lining with attached slag. The latter was from the dormitory and may be associated with a furnace beneath the dormitory. Some other debris was also recovered from the east cloister walk. Ironworking would have been required for a variety of needs including smithing. There is also fuel ash slag and vitrified clay, probably from metalworking.