Las Médulas

Las Médulas
UNESCO World Heritage Site
Panorámica de Las Médulas.jpg
Panoramic view of Las Médulas
LocationProvince of León, Castile and León, Spain
  1. Zone principal de la mina de oro de Las Médulas
  2. Estéiles de la Balouta
  3. Estéiles de Valdebría
  4. Estéiles de Yeres
Inscription1997 (21st Session)
Area2,208.2 ha (5,457 acres)
Coordinates42°28′9.8″N 6°46′14.7″W / 42°28′9.8″N 6°46′14.7″W / 42.469389; -6.770750

Las Médulas is a historic gold-mining site near the town of Ponferrada in the comarca of El Bierzo (province of León, Castile and León, Spain). It was the most important gold mine, as well as the largest open-pit gold mine, in the entire Roman Empire.[1] Las Médulas Cultural Landscape is listed by UNESCO as a World Heritage Site. Advanced aerial surveys conducted in 2014 using LIDAR have confirmed the wide extent of the Roman-era works.[2]

The spectacular landscape of Las Médulas resulted from the ruina montium (wrecking of the mountains), a Roman mining technique described by Pliny the Elder in 77 AD.[3][4] The technique employed was a type of hydraulic mining which involved undermining a mountain with large quantities of water. The water was supplied by interbasin transfer. At least seven long aqueducts tapped the streams of the La Cabrera district (where the rainfall in the mountains is relatively high) at a range of altitudes. The same aqueducts were used to wash the extensive alluvial gold deposits.[5]

The area Hispania Tarraconensis was conquered in 25 BC by the emperor Augustus. Prior to the Roman conquest the indigenous inhabitants obtained gold from alluvial deposits. Large-scale production did not begin until the second half of the 1st century AD.[6]

Mining technique

Pliny the Elder, who was a procurator in the region in 74 AD, described a technique of hydraulic mining that may be based on direct observation at Las Médulas:

What happens is far beyond the work of giants. The mountains are bored with corridors and galleries made by lamplight with a duration that is used to measure the shifts. For months, the miners cannot see the sunlight and many of them die inside the tunnels. This type of mine has been given the name of ruina montium. The cracks made in the entrails of the stone are so dangerous that it would be easier to find purpurine or pearls at the bottom of the sea than make scars in the rock. How dangerous we have made the Earth![7]

Rock-cut aqueduct in La Cabrera

Pliny also describes the methods used to wash the ores using smaller streams on riffle tables to enable the heavy gold particles to be collected. Detailed discussion of the methods of underground mining follows, once the alluvial placer deposits had been exhausted and the mother lode sought and discovered. Many such deep mines have been found in the mountains around Las Médulas. Mining would start with the building of aqueducts and tanks above the mineral veins, and a method called hushing used to expose the veins under the overburden.

The remains of such a system have been well studied at Dolaucothi Gold Mines, a smaller-scale site in South Wales. Opencast methods would be pursued by fire-setting, which involved building fires against the rock and quenching with water. The weakened rock could then be attacked mechanically and the debris swept away by waves of water. Only when all opencast work was uneconomical would the vein be pursued by tunnelling and stoping.

The metallurgic "Orellán" town in Las Médulas (fl. 1st–2nd centuries BC)

Pliny also stated that 20,000 Roman pounds (6,560 kg) of gold were extracted each year.[8] The exploitation, involving 60,000 free workers, brought 5,000,000 Roman pounds (1,640,000 kg) in 250 years.

Other Languages
العربية: لاس مدولاس
asturianu: Las Médulas
català: Les Mèdules
čeština: Las Médulas
Deutsch: Las Médulas
Ελληνικά: Λας Μέδουλας
español: Las Médulas
Esperanto: Las Médulas
euskara: Las Médulas
français: Las Médulas
galego: As Médulas
հայերեն: Լաս Մեդուլաս
hrvatski: Las Médulas
italiano: Las Médulas
ქართული: ლას-მედულასი
Lëtzebuergesch: Las Médulas
lietuvių: Las Médulas
magyar: Las Médulas
Nederlands: Las Médulas
polski: Las Médulas
português: Las Médulas
русский: Лас-Медулас
Simple English: Las Médulas
slovenčina: Las Médulas
srpskohrvatski / српскохрватски: Las Médulas
svenska: Las Médulas
Türkçe: Las Médulas
Tiếng Việt: Las Médulas