Aerial mapping in Spain has uncovered an ancient Roman gold mine.
Researchers from the University of Salamanca used aerial mapping and LiDAR to find the mine, which was built more than 2000 years ago, according to Science Daily.
The gold mine complex, dubbed Las Medulas, was built two millennia ago, and features complex hydraulic works, which were used to divert water to the site for processing.
The mine, in Leon, is believed to be the largest opencut gold pit of the entire Roman Empire.
"The volume of earth exploited is much greater than previously thought and the works performed are impressive, having achieved actual river captures, which makes this valley extremely important in the context of Roman mining in the north-east of the Iberian Peninsula," Javier Fernández Lozano, geologist at the University of Salamanca and co-author of the study, said.
He went on to state: “We have established that the labour that went into extracting the resource until its exhaustion was so intensive that after removing the gold from surface sediments, operations continued until reaching the rocks with the auriferous quartz veins underneath.”
Fernandez Lozano said that the mine would not have been found without the use of the commonly used mining mapping LiDAR technology.
He went on to say "our intention is to continue working with this technique to learn more about mineral mining in the Roman Empire and clear up any mysteries such as why Rome abandoned such a precious resource as gold from one day to the next”.
Spain was mined extensively in Roman times, with the landscapes of the Las Medulas region created by the Roman mining techniques, described by Pliny the Elder in 77AD, which used hydraulic mining to undermine mountains using water transferred to the area by aqueducts.
Approximately 1.65 million kilograms of gold was extracted over the site’s 250 year mine life.
Pictured below: The Las Medulas