Exceptional wooden artefacts from the Celtic period
Excavations in the "la Digue” workshop area in Marsal have yielded a series of wooden artefacts that have been exceptionally well preserved in an anaerobic environment. The saltworkers of the 6th century BC built platforms of branches to enable them to stay dry as they walked through the wet areas around the edge of the brine settling and enrichment basins. The basins themselves were built on wattle frames interwoven with stakes. Numerous wood shavings resulting from the manufacture of these walls were found abandoned in situ.
Several fragments of wooden objects were also collected. These are mainly pieces of bowl or ladle-type vessels. The base of a brine tub, 25 cm in diameter, was discovered. It is made up of an assembly of curved and sewn planks. A piece of rope was used to bring up the brine from the bottom of the salt wells. Several pieces of unknown purpose have been found, such as a circular puck with a hole in the centre, 8 cm in diameter, which could be linked to spinning work.
Seasonal work?
The processes involved in pre-treating the brine in order to bring it to saturation point, required maximum sunlight and had to be carried out between spring and summer. Excavation of the "La Digue" workshop area in Marsal has shown that the production areas were regularly flooded during the cold season, when salt production had to be halted.
Specialised ancillary activities — in particular metallurgy — could then be carried out outside the salt production season. At the end of this "rest" for the workshops, the saltworkers were kept busy maintaining and repairing the equipment, in particular the furnaces, whose heating chambers might have been recoated. The succession of these repairs suggests that the furnaces lasted between ten and fifteen years.
The end of Celtic salt-making workshops
Excavations in the "la Digue" workshop area in Marsal and the "Burthecourt" workshop area in Salonnes reveal a significant increase in seasonal flooding, which submerged the salt-making facilities between the end of the 6th century and the beginning of the 5th century BC. At this point, the Celtic salt-making workshops throughout the Seille valley ceased production for good.
The mining sites then moved to several areas that had the advantage of being out of the water, such as the market towns of Marsal, Moyenvic and Vic-sur-Seille. This widespread decline was probably due to more than just environmental causes. The end of the Celtic salt-making workshops in the Seille valley coincided with the end of the economic and social model of the Early Iron Age, which saw the collapse of the "princely" aristocracies of the 6th century BC.
What sort of volumes were produced?
Given the number of salt workshops operating at the same time during the second half of the 6th century BC, the quantity of salt produced in the Seille may have reached several thousand tonnes a year during the Celtic period of the Early Iron Age.
It was much higher during the Gallic period at the end of the Late Iron Age, when the volume of waste accumulated during the 2nd and 1st centuries BC means that tens of thousands of tonnes of salt were extracted every year.
These production volumes obviously exceeded local consumption needs. Production at the Celtic and Gaulish saltworks on the Seille probably supplied large populations towards the Rhineland and the Paris Basin.
