Point 5. The metal workshop
This is building IV, and consists of one free-standing construction slightly to the west of the centre of the settlement. It was a completely new building which made no use of existing structures. The walls were between 50 and 60 centimetres thick and in this case the stone-built part does not seem to have been very high, indicating that above a certain height the walls were built up with earth.
While little remains of the most northerly part, the building would seem to have had a square floor plan, measuring 12.5 metres along the side, taking up 155m2 of ground. The building was divided into two parts. The distribution and features of the northernmost one, largely disappeared, are unknown. The southern part had three rooms connected to one another by openings 1.15 metres wide. The eastern room is more square, while the other two are rectangular, measuring 6.4 by 3.2m. All three rooms had hearths in the centre, built with a clay bottom, and two of them have decoration round the sides consisting of two slots a centimetre wide. Several small reducing ovens have also been found beside them.
The westernmost room would have been where metals were smelted and reduced, for which reason it was probably open to the sky or only partly covered. The other two would be storerooms or workshops, and there are supporting points in the more easterly of them which would indicate that there was a ceiling or furniture of some kind: shelves or similar, tables, etc.
Iron slag and tools, pieces of azurite (a mineral with a high copper content) and bronze tools as well as lead castings show that these things were used. Analysis of residual soils has revealed work with tin, a new alloy from the early 1st century BC onwards, and the existence of gold and silver working. The latter activity is backed up by the finding of a gold earring in building II, the existence of gold mining activity in the Miocene alluvial deposits in the valleys of Cerdanya and by the discovery in crucibles of cinnabar, a mineral necessary to amalgamate gold and used to gild objects in antiquity, probably traded from the mines of Almadén (Ciudad Real province, Spain)
Images: Ground plan of the structures of building IV in red
Images: Hypothetical plan of the structures of building IV
Illustration in colour: Axonometric view of building IV showing some of the metal working activities inside
Image: Gold earring found at Castellot
Image: Iron slag found at Castellot
Image: Lead casting found at Castellot
Image: Bronze spatula found at Castellot