The tin mine of Vale do Mouro (Coriscada, Portugal). A preliminary study

This poster presents the first results about tin mining vestiges detected on the archaeological site of Vale do Mouro, in Coriscada (N Portugal). This site is a roman villa (IInd-IVth c. AD) where a production of wine and olive oil has been identified. The mining remains are located nearby the villa and are composed by numerous opencast trenches, nowadays partially backfilled. One of the buildings in the villa revealed a significant fill of its base floor with quartz pieces, which were most likely waste heaps of the ore processing phase. Analyses showed the presence of cassiterite inclusions within the quartz. Less than 50 m away from this building is the nearest opencast trench, which was excavated in its upper part for this first study. The excavation showed that the trench was following a vein, and it was possible to identify tool marks on the granitic walls. The shape of the works and the techniques used for sinking are consistent with a roman exploitation. Likely, the other nearby backfilled mines could also be of this period. The sources of antique tin are known in broad lines (European Occident) but precise elements about the mines which were actually exploited during Roman period are very scarce. The site of Vale do Mouro gives us an opportunity to bring data about tin procurement and about the way this production was integrated within the villa’s economy.