During the Roman rule over Galicia and the rest of Iberic Peninsular an intense and varied mining activity was developed over numerous deposits. Gold mining being the main activity in our area. Referencing the topology, basically there are two types of deposits; these are known as the primary and secondary deposits. In the primary deposits the gold was extracted straight from the seams and the secondary deposits consisted of material eroded from the primary deposits.
The Os Medos mine is a secondary deposit open cast Roman gold mine. In the early days of mining they washed the surface to find the gold, then later they developed more elaborate systems which involved a series of interlocking ditches, the tops of which are well conserved. The area of exploitation is divided into two levels. On one side, by the river Saa, the lower level starts almost at the river bank. It’s structures are difficult to recognise nowadays. On the other side is the area with the interlocking ditches. This side is bigger and we can clearly make out the aggregate deposits resulting from the washing of the gold bearing gravels.