This dense slag comes from a bloomery furnace used for smelting iron from ore. As the temperature in the charcoal-fuelled furnace rose, the ore would begin to melt, but the first molten material that dribbled to the bottom of the furnace was not the iron itself. This hot liquid was tapped off – drained out of the furnace through a specially constructed opening – and flowed out in small rivulets. It was left to cool before being hacked away and discarded.
This example shows the ends of some of the flows. Had it been excavated in situ where it cooled, it would have indicated the direction in which the furnace could be found.
More than 3kg of this type of slag was excavated from a 1 cubic metre test pit, and similar material has been found nearby, indicating that this site saw the firing of numerous furnaces over a period of time. The Iron Age date is tentative, and is based on the identification of a single sherd of pottery (haematite coated ware) excavated from the same source as this artefact. Finds resembling this may date from the Iron Age to the Tudor period.
Period: Iron Age
Find spot: 13 West Town Lane, Brislington, Bristol. ST 62097032
Exhibit contributed by Alan & Margaret Bale
Text written by Ken Taylor, in 2011
Photographer: Steve Hallam
Acquisition number: 110923a3
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