A workshop dated to the old iron age at Koussane

International audienceA horizontal digging of 35 m2 on the archaeological deposit of Koussane allowed the excavation of iron-making remains in relation with a direct reduction operation of siliceous iron ore. Two fragments of charcoal included in a slag give an age C14 of 1715 ± 55 BP in agreement with the chronostratigraphy. The furnace used for this operation consisted of a slightly hemispherical shallow pit with a cell built with coils and coated with clay. Both the shape and the height of this superstructure are indeterminable from remains. A nozzle, arranged obliquely through the body of the oven and associated with bellows, favoured the formation of an iron sponge above the liquid slag as revealed by metallographic examinations. This latter solidified in the pit in a 90 kg block, and subequently the construction in elevation was moved two to three meters to allow the removal of the iron sponge. The chemical analyses made on the ore and on the slag lead to an estimate for the mass of raw metal produced of around 11,5 kg