The gold mine of Las Medulas (Spain) was cultivated between the 1st and the 2nd century AD by the Romans with local population workforce: the Iberians. The metal, in Tertiary alluvial deposits (Miocene), was extracted by hydraulic force. The water, derived from the Aquilianos mountains, flew in artificial tunnels and the pressure generated by compressed air shattered the gold layers. This system was called by the roman historian Plinio the elder: Ruina Montium. The gold contained in the debris was recovered by washing them in channels and was accumulated in sterile fans located downstream of the exploitation fronts. The site is UNESCO World Heritage Site.
