Aerial Laser Uncovers Ancient Roman Goldmines in Spain

Researchers have just uncovered the ancient remains of Roman goldmines with the help of a laser. Scientists have used the Light Detection and Ranging (LiDAR) laser system to detect a complex gold mining network in addition to hydraulic works, such as river diversions, to divert water to the mines.

"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 northeast of the Iberian Peninsula," said Javier Fernandez Lozano, co-author of the new study, in a news release.

Researchers have long known that the Las Medulas goldmine was the largest opencast goldmine of the Roman Empire. Until now, though, they hadn't realized exactly how extensive these mining operations were. LiDAR actually detected channels, reservoirs and a double river diversion that was all used to help extract gold from the mine.

The findings only come after the use of LiDAR, which is made up of a laser sensor which scans the ground from an aircraft or drone with geographical references provided by GPS ground stations. The data that LiDAR obtains is represented by point clouds, which are then processed with a piece of software to construct a cartographic model where the forms are identified. In this case, the scientists spotted old reservoirs and channels.

"We have established that the labor 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," said Fernandez Lozano.

The findings not only reveal a bit more about these ancient mining operations; they also show that LiDAR can be a valuable tool in terms of uncovering hidden, ancient structures. Currently, the researchers hope to continue working with this technique in order to learn more about mineral mining in the Roman Empire and clear up mysteries, such as why Rome abandoned the gold mine.

The findings are published in the Journal of Archaeological Science.