Las Médulas is an area located in NW-Spain featuring a landscape environment formed by an old Roman gold mining operation. It is thought to be the largest open-pit gold mine in the Roman Empire and it was exploited during I and II centuries AD. The archaeological site and its environment were declared UNESCO World Heritage in 1997, based on its value as a cultural landscape. The most spectacular mining system used there was the one that Pliny the Elder called "Ruina Montium", that is, "the collapse of the mountains". This technique was applied to reach in one go the conglomerate levels richer in gold (Santalla formation), removing a thick cover of conglomerate block-in-matrix (bimrock) type waste. Unfortunately, there are no obvious remains of this procedure. In this multidisciplinary study in progress, archaeologists and engineers work together to better understand the detailed process used by the Romans to cave the mountains.
Las Médulas was included in 1997 in the List of the UNESCO World Heritage Sites for being one of the best examples of the mark that History has left on the Landscape. It occupies an extension of about 20 km2. We are not just referring to leftovers, materials, more or less spectacular, of a past activity, but to the possibility to understand in-situ the permanent relationship between society and the territory it occupies, between communities and the natural resources they exploit, and ultimately, the social relations in which that occupation and exploitation develop. The remains of Roman mining in Las Médulas make it an outstanding example of ancient technology. But the meaning of the gold production thus obtained can only be understood within the complex process history of which it was a part (Sánchez-Palencia et al. 1998 & 2000; Pérez-García et al. 2000).
The area started to be mined some decades after the pacification of the area in the Cantabrian wars (29-19 BC). The value of gold in the Roman Empire cannot be understood, as nowadays, in profitability terms. It had though a strategic importance due to its use for minting the gold coin, the aureus, which, with silver too, constituted the basis of the Roman monetary system since the time of Augustus. This allowed economic stability of the Empire precisely in the time slot when the area was mined. Mining proceeded until the transition from the II and III centuries AD. The main reason of mine closure must be sought in the crisis that the Roman monetary system experienced at that time.
