Roman denarius, the standard Roman silver coin. (Image by Jean Milot).
A team of French and Spanish researchers evaluated silver sources from different mining provinces in the Iberian Peninsula, which includes Spain and Portugal, to determine which locations may have been mined for silver to produce Roman coinage.
According to Jean Milot, lead author of the study published in the journal Geology, the control of silver sources was a major geopolitical issue. Thus, the identification of Roman silver sources may help archaeologists to reconstruct ancient fluxes of precious metals and to answer important historical questions.
Silver became widely used for coinage in the Roman world from the 7th century BCE onward and provided a standardized monetary system for ancient Mediterranean civilizations.
The problem is that it is difficult to determine which deposits Roman miners exploited because most of them have been depleted.
However, the ones that still stand in the southern region contain galena, which is the main ore of lead and an important source of silver. To track the source of Roman silver, the team analyzed the silver and lead compositions of galena samples from some of those deposits and compared the results to the chemical signatures of silver Roman coins.
Iberian galena sample. (Image by Jean Milot).
They identified two different types of galena deposits based on the silver elemental composition of the samples: silver-rich galena that would have been a likely source for Roman coinage, and silver-poor galena that would have been exploited for lead and would have been of lower economic importance.
Yet, few of the ore samples had a composition that fit the silver elemental composition of the Roman silver coins. Silver-bearing ores spanned a wide range in compositional variability, but Roman coins notably have a very narrow elemental composition range.
Based on the lead elemental signatures of the galena samples, the ore deposits from southeastern Spain best fit the composition of Roman coins, suggesting that these deposits were a major source of Roman silver. Both silver-rich and silver-poor galena deposits were likely exploited there, with the extracted lead from silver-poor galena able to be mixed with other ores to extract silver.
These results based on chemical analyses are also consistent with archaeological evidence for ancient mining exploitation in the region.
“This work needs to be extended to the silver-rich region in which coinage was actually invented in the 6th century BCE, Greece and Asia Minor (modern Turkey),” Milot said in a media statement. “The method we describe here will allow us to recognize the lost ore fields which supplied silver to the Eastern Mediterranean empires from the Bronze Age to the collapse of Hellenistic kingdoms.”
The ancient Romans were prolific silver miners and refiners, with some estimates suggesting that they produced over 10,000 tons of silver during their time. The majority of this silver came from mines in Spain, which the Romans conquered in the 2nd century BC.
Mar 27, 2023
Where did Romans get silver from?
The Romans obtained most of their silver from the very rich mines of Spain, which had been previously worked by the Phoenicians and Carthaginians.
Where did Rome get silver?
Iberia (modern Spain and Portugal) was possibly the Roman province richest in mineral ore, containing deposits of gold, silver, copper, tin, lead, iron, and mercury). From its acquisition after the Second Punic War to the Fall of Rome, Iberia continued to produce a significant amount of Roman metals.
What was the largest Roman silver mine?
Their magnitude far exceeded anything that came before. During that period, Delgado says, Riotinto was the largest silver and copper mining operation in the Roman Empire.
Sep 28, 2010
Where were Roman silver mines?
A number of Roman mines have been excavated and documented. Examples include the gold mine at Dolaucothi in Wales, and the extensive silver workings at Rio Tinto, Spain. Mining is a destructive process, so much evidence has been erased by Roman and later working.
Riotinto
The Mines that Built Empires
by BARRY YEOMAN on SEPTEMBER 28, 2010
For 5,000 years, Spain’s mineral riches created cash economies and global pollution.
A shorter version was published in Archaeology.
Roman water wheel, found in South Lode, Riotinto Mines, 1919. Photo courtesy of Aquilino Delgado.
AQUILINO DELGADO DOMÍNGUEZ UNLOCKS the ornamental metal door and waves me inside the warehouse of the Riotinto Mining Museum in southwestern Spain. He makes a beeline to a cardboard box sitting on a waist-high table. Inside is a gray plastic bag containing pieces of a Roman water wheel used during the first or second century A.D. to pump water out of the nearby mines. For 5,000 years, the metals dug from these mines have provided the wealth that sustained civilizations.
Miners discovered the wooden wheel during World War I. Now, Delgado is preparing to analyze the fragments using radiocarbon and tree-ring dating. The archaeologist opens the bag, thrusts his nose inside, and breathes deeply. “Smell this,” he says. The sulfur odor is not what I expected: a mixture of chocolate and licorice, sweet but not cloying. “That’s the smell I remember from my childhood,” he says.
In 1983, Delgado’s maternal grandfather—a supervisor in Cerro Colorado, the second-largest mine in the Riotinto complex—invited his four oldest grandchildren to see firsthand how five generations of relatives had earned a living. Delgado, who was nine, was the only one to accept the offer. For the next two years, during school breaks, Delgado’s grandfather dressed him in boots, a helmet, and an adult miner’s uniform—he was a tall boy—and took him through the copper, gold, and silver mines. “What my grandfather did with me was very common,” he says. “It was a way to dignify their labor.”
Delgado figures that if he were born even five years earlier, he might have ended up working in the mines himself. Instead, he left home to study archaeology at the University of Huelva, 45 miles to the south. Now, at age 36, he directs the museum dedicated to the mines where both his grandfathers once worked.
Riotinto is part of the Iberian Pyrite Belt, a mineral deposit that stretches from Spain into Portugal. It is one of the largest known mining complexes in the ancient world. Starting as a surface operation focused on copper minerals, it eventually became an industrial-scale enterprise until it finally closed in 2001 amid falling copper prices. “The name Riotinto has something of a magical connotation,” wrote University of Sevilla archaeologists Antonio Blanco Freijeiro and José María Luzón Nogué in 1969. “It has been called the geologist’s paradise because at almost no other place on the earth has nature exposed in one spot such richness and variety of minerals.”
Now that the industry is gone (for the time being, at least), Delgado and other researchers are studying Riotinto and some neighboring sites to answer fundamental questions about how metals were extracted and processed in the ancient world. But they’re also examining the nature of work, the rise of globalization, and the legacy of environmental contamination.
THE BUS FROM HUELVA TO THE VILLAGE of Minas de Riotinto is driven by Delgado’s father, one of the few men in his family who didn’t work in the mines. It takes us through workaday pueblos of whitewashed and tiled buildings with wrought-iron balconies and terracotta roofs. Waiting passengers huddle against walls, trying to protect themselves from a cold rain that has persisted for weeks. As we near Riotinto, the road starts climbing abruptly, and caution signs warn that this is a zone of frequent accidents.
On the far side of town, the highway passes modern open-cast pits, their sides stepped in 40-foot levels like amphitheaters built for giants. Visiting in the late 1980s, archaeologist Lynn Willies of England’s Peak District Mining Museum described it as a landscape turned upside-down: “The hills have literally been turned into valleys, and the valleys made into hills.” Even more striking than the topography is the landscape’s color palette: crimsons, blue-grays, and ochres, which give the place an otherworldly feel. Naturally dissolving iron, a process believed to predate the mines, has dyed the acidic river “tinto,” or wine-colored. So otherworldly is Riotinto that NASA has used robots to drill its soil—practice for the search for underground life on Mars.
Local folklore places King Solomon’s mines at Riotinto, though a more factual history has been more difficult to write. “Its birth is shrouded in the mists of antiquity,” wrote William Giles Nash, a Rio Tinto Company employee, in 1904. Archaeologists now know that the area’s Copper Age inhabitants were extracting malachite and azurite, two copper-rich minerals, during the third millennium B.C. Inside Riotinto’s museum is a 5,000-year-old stone hammer found in one of the mines during the 1980s. These hammers were used to cut trenches in the slate outcroppings—the earliest form of mining at the site.
A 1990 excavation at Riotinto. Photo by Juan Aurelio Pérez Macías, courtesy of Aquilino Delgado.
The Phoenicians arrived in Spain around 1100 B.C.—their ships filled with ceramics, jewelry, and textiles for trading—and moved inland during the 9th century B.C. “They didn’t bring weapons,” says Thomas Schattner, a professor of classical archaeology at Germany’s University of Giessen. “They walked in, they exchanged goods with the indigenous people, and they were received.” There is no archeological evidence of hostile attacks, Schattner says, which lends credence to the written accounts of peaceful trading.
At Riotinto, the Phoenicians found the silver and copper mines run by an indigenous people called the Tartessians. Even after the foreigners’ arrival, the mining operations remained in local hands—though the amount of Phoenician influence remains a point of contention. “None,” says Delgado, dismissing those who believe, in his words, that “without the arrival of foreigners, the indigenous people would still be like Adam and Eve.” He argues that that only a few Phoenicians lived in the area, where they served as commercial agents. Schattner calls that answer “one-dimensional,” noting that both written evidence and the size of the slag heaps show that silver production spiked at mines like Riotinto after the Phoenicians’ arrival. Delgado contends this is solely because of higher demand; Schattner disagrees. Among the finds at Riotinto, Schattner says, are rectangular clay nozzles that had been attached to leather bellows, which pumped air into smelting furnaces. “The introduction of bellows is one of the most important contributions of Phoenician technology,” he says. “It permits bigger ovens, higher temperatures, more successful melting, and much bigger amounts of metal. It’s the beginning of industrial production. You would not obtain this amount of silver by using the old-fashioned technology.”
Beyond mining, the Phoenician arrival sparked “a kind of globalization,” says Schattner. In the seventh century B.C., the eastern Mediterranean was shifting toward a coin-based economy, and the Phoenicians needed silver to decorate their temples and pay their debts to the Assyrian empire. Silver—which was shipped off the Iberian Peninsula in bars or ingots, according to shipwreck evidence—was the perfect currency, he says: rare enough for coins to have value but common enough for many people to participate in the economy. “Without the silver mines of southern Spain, the development of money would have been quite different—based on a medium that was less ideal,” Schattner says.
The globalization was cultural, too, Schattner argues. He has been excavating at Castro Cerquillo, a Phoenician-era village outside the Tharsis mines, 40 miles west of Riotinto. There, he says, “we made the astonishing observation that the new settlements of the indigenous people are being built in an Eastern manner, with orthogonal streets like New York, at right angles, making blocks—a very modern manner for that time.” While the Phoenicians were extractors of wealth, Schattner says, they were also “distributors of ideas—for cities, for material culture, for houses, for living.”
THE ROMANS TOOK OVER RIOTINTO in 206 B.C. after defeating and expelling the Carthaginians, who had occupied the region since about 535 B.C. With the technical knowledge of Rome’s military engineers and the availability of slave and convict labor, the Roman operations at Riotinto grew colossally, peaking from A.D. 70 to 180. Their magnitude far exceeded anything that came before. During that period, Delgado says, Riotinto was the largest silver and copper mining operation in the Roman Empire.
A stone hammer from the Cuchillares mine. Photo courtesy of Aquilino Delgado.
“The excavations in the mines themselves, the investigations of the slag heaps, and the cemeteries and mining settlements show that the sheer scale is much more important in the Roman period,” says Jonathan Edmondson, chair of the history department at York University in Toronto. “With thousands of laborers and Roman soldiers and administrators camped out, they would have been hives of activity.”
The Romans mined Riotinto by digging shafts of up to 450 feet deep, which required elaborate ventilation and drainage systems, including wooden water wheels and a system of gently sloping drainage channels that remained in use well into the 20th century. They also developed a sophisticated system of governance. Two bronze tablets unearthed at Aljustrel, another Pyrite Belt mine across the Portuguese border, spelled out the rules by which the Roman government would lease Iberia’s mines to individual conductores, who paid 50 percent commission on the ore they excavated. The tablets, discovered in 1876 and 1906, also covered mine safety, the treatment of slaves, and the granting of concessions to barbers, auctioneers, and cobblers. Bathhouse owners, who bought franchises, had to keep the water heated year-round, polish the metalwork every month, and admit women and men at specific hours.
The scale of mining at Riotinto fundamentally altered the Roman economy. “Basically, it ensured Rome a constant supply of fresh metal for increased minting of silver and lower-denomination copper-based coins,” says Edmondson. Rome used silverdenariito pay and feed its army, fund public building programs in its capital city, and subsidize the price of (and eventually allow free distribution of) grain to the city’s residents. But following the invasion of Spain by the North African Mauri in the late second century, mining activity dropped off and thedenariusplummeted from 97 percent silver to 40 percent, leading to outsized inflation as Roman minted ever-less-valuable coinage. “The Roman state experienced major problems, since taxes were paid in coin,” Edmondson notes. “People started handing over these debased coins in payment of taxes, while hoarding the [older] higher-percentage silver coins.” By the fourth century, he says, gold replaced silver as Rome’s main currency.
After the Roman era, the Visigoths allowed Riotinto to go dormant, though the mines did experience a small-scale resurrection during the Islamic Period (particularly the 10th through 13th centuries). They weren’t rediscovered until 1556, when a priest named Diego Delgado set out to search for new mines at the behest of Spain’s King Phillip II. “In these parts I have discovered very important secrets,” wrote Delgado in a letter to the king, in which he enclosed three buttons of silver. But little came of the mines until 1873, when the British-based Rio Tinto Company developed them into a gigantic operation with open-cast pits and its own railway. The company built a Victorian village called Bella Vista (cricket field and all), along with its own hospital and school system. At the peak, in 1910, 17,822 people worked for the mining company, in a landscape altered beyond recognition.
That was the culture into which Aquilino Delgado Domínguez was born.
DELGADO’S RELATIVES’ WORK WAS NOT SO DIFFERENT from that of their forebears. “For 2,000 years it was done by hand, by pick and shovel,” he says. His paternal grandfather, who died when Delgado was six, worked one-third of a mile underground, naked except for helmet and boots because of the 120-degree heat. The work was not only brutal; it was also unhealthy: The archaeologist vividly remembers the coughs of neighbors who had contracted the incurable lung disease silicosis, which often afflicts miners who inhale silica dust.
Debilitating as it was, mining kept the economy humming in this remote corner of Spain. When Riotinto’s owners introduced labor-saving technologies in the 1960s and ’70s—including automatic loaders that could be guided into the most dangerous areas by remote control—miners sabotaged the equipment out of fear for their jobs. “They would put pyrite powder in the injectors to break them down,” Delgado says. “They would do the same with the automatic drills.”
Starting at age four, Delgado went with his maternal grandfather to an all-male social club where miners drank coffee and aguardiente (a strong liquor made from anise), watched soccer, and played cards. He loved listening as the older men chatted. “You cannot find these stories in any history book,” he says. “For example, my grandfather’s work documents talk about when he was given a break for the birth of my mother, or when he was given a pair of new boots. However, they do not mention how scared they used to be every time they went down into the mine, or the fact that alcohol consumption was really high. Many of the workers used to drink to forget the fact that you could lose your life every time you went to work.”
“My grandfather had to walk five kilometers to go to work and another five kilometers to get home,” Delgado says. “After work he would tend his vegetable garden. Of course, this activity helped with the household budget. But I really believe he did it because he had the need to see something grow.”
As a college history major, Delgado went on some nearby digs, accompanied by Juan Aurelio Pérez Macías, the former staff archeologist for Rio Tinto Minera S.A. (the mines’ then-owner) and now an archaeology professor at the University of Huelva. Delgado loved the tangibility of archaeology. “What you find in an excavation is a fact,” he says. “It is the truth. People who write history based on documents call us cacharreros, pottery dealers. And we call them library rats.”
After graduation—he’s now finishing up his doctoral dissertation—Delgado worked for a company that did archeology at construction sites. Seven years ago, he was hired as the director of the Riotinto Mining Museum, which is housed in the hospital where he was born.
IRONICALLY, DELGADO HAS NEVER EXCAVATED in his hometown. Although he has dug elsewhere in the Pyrite Belt, archaeologists have been denied access to Riotinto by the landowners and local government officials since 1993. Still, Riotinto was a fertile excavation site from the 1960s through the ’90s. Delgado’s mentor Pérez dug there for twenty of those years. Pérez uncovered lamps, domestic pottery, statues, amphorae, and metal objects such as buckets, safety pins, and mirrors. Below that, he also found Phoenician artifacts. As a result of those three decades of systematic digging—plus a century of more casual finds—the Riotinto Mining Museum has an extensive collection, including 900 pieces of glassware and 500 Roman-era iron hammers. (“I managed to recover 70 Roman hammers from people’s homes just by convincing them that the museum was a much better place for those pieces,” Delgado says. “I would not have been able to achieve that if I was not from here.”) This gives Delgado and Pérez abundant research material.
A Phoenician miner lamp. Photo courtesy of Aquilino Delgado.
Much of their research centers on ancient metallurgy. But Delgado has also used physical evidence—lamps, tools, household utensils—to reconstruct the lives of Roman miners. During our interview, he ticks off “a normal day in the life” of such a worker: “Really early, they would get up and havebreakfast, which would consist of a purée made mainly of wheat and bread, orposca—water, vinegar and wine—with some cheese and bread,” he says. “They would grab their lamps and tools and would head up to the mine to excavate for minerals.” The work was exhausting—the museum’s collection includes a Roman hammer that weighs 16 pounds. And the air was toxic, Delgado says, even above ground. Studies of a crematory oven from that era point to an outsized infant-mortality rate. “It was a highly sulfuric environment,” he explains, “so any small child who was affected by asthma or any other respiratory problem could die very quickly.”
Lunch often included a salty fish sauce to balance out their high-potassium diets. Afterward, the miners would “keep working until about four or five p.m. or until the lamp had extinguished,” Delgado says. “Then they would go back home, and then to the public baths, where they would get clean and spend some time with friends. They would have some wine because, even though in Roman times they already had beer, it was not considered elegant to drink beer.”
Delgado and Pérez are passionate about dispelling the notion that all Roman miners were slaves. Evidence from Riotinto’s graves shows many workers had last names, which meant that they had been free men. Delgado worries that the popular conception comes from films like Barabbas, the 1961 classic in which the title character, played by Anthony Quinn, is sentenced to work in Sicily’s sulfur mines—shackled, beaten, never allowed to see daylight. Director Dino De Laurentiis’ hellish scenes “are iconic images that stick in people’s heads,” Delgado says.
Pérez describes the Roman settlements at Riotinto as, in some ways, unextraordinary. “The standard of living would have been very similar to any other Roman town,” he says. “The population was not just composed of slaves but of citizens who had purchasing power to buy the best Roman products.” There were slaves, too, Pérez adds, “but a slave could have been a teacher, or a smelting technician who would have been paid for his work. Although he would still depend on a master, he would have had money and savings.”
For the slaves whowerecondemned to the mines, Delgado says life was not unlike the scenes inBarabbas.“They would be chained at the neck,” he says, “and their working day would be determined by how long their lamp would last, about 11 hours. They would be woken up really early in the morning. They would be fed a very strongposcato hydrate them and make them drunk, because if they were a bit drunk they would not be as conscientious of their situation. They would also be fed some bread and they would probably not get anything else until the following day. They would feed them enough to be able to go through a working day, but not enough to put up resistance.” Human bones found in slag piles show that enslaved miners were not entitled to burials. Instead, Delgado says, “they were thrown out with the slag and the garbage.”
ANCIENT MINING HAS GIVEN THE IBERIAN PYRITE BELT another grim legacy, as is one of the earliest sources of global pollution. In the 1990s, a team of scientists headed by Australian physicist Kevin Rosman analyzed the lead content of a 1.9-mile-long ice core drilled in Greenland. They found “unequivocal evidence” of massive pollution during Roman and Carthaginian times, with Spain emerging as the main source. Seventy percent of the lead in the ice core that dated between 150 B.C. and A.D. 50 had the chemical signature of Riotinto. Lead, a byproduct of silver mining, was used in everything from shipbuilding to winemaking.
Roman iron tools. Photo courtesy of Aquilino Delgado.
Other research dates the damage even earlier. In a study published in 2000, a group of Spanish and U.S. scientists analyzed a 164-foot sediment core from a site near Riotinto. They discovered significant sulfide and heavy-metal pollution going back 4,800 years. “The contamination started pretty much at the initiation of mining,” says co-author Jeffrey Ryan, chair of geology at the University of South Florida. To get the valuable metals, the sulfide ores were burned in large furnaces that released sulfur-rich gases. Most striking, Ryan says, was that pollutant levels didn’t decrease as mining waned. “You’ve taken the rocks from deep in the earth. You’ve pulled them to the surface. You’ve broken them into little pieces. And you’ve exposed the sulfide minerals to the atmosphere,” he says. “When sulfide is exposed to the atmosphere, it reacts with the oxygen to form sulfur dioxide and leaves behind a heavy-metal effluent.”
When Diego Delgado, the Spanish priest, came upon Riotinto in 1556, he reported to King Felipe II, “In this river there is no type of fish nor living creature, and neither people nor animals drink these waters.” Even today, the Tinto and Odiel rivers are poisoned with arsenic and metals, raising concerns about water quality in the nearby Atlantic Ocean and Mediterranean Sea.
At the University of Huelva, I talk with mineralogist Reinaldo Sáez Ramos, whose studies combine archaeology and geology. Sáez talks about his work at Cabezo Juré, an ancient copper-mining community just outside Tharsis. “When we did this excavation, we realized that the villagers ate the shells of a particular mollusk,” he says. “After analyzing those shells, we found out they contained zinc, copper, and arsenic in a quantity that was much higher than what it is considered normal.” By studying clamshells throughout the region, Sáez and his colleagues concluded that the nearby Gulf of Cádiz became polluted with heavy metals around 2475 B.C.—just as large-scale mining and smelting were getting underway. The researchers did find a dip in pollution levels 200 years later when mining ceased. No one knows why mining stopped, but tree-pollen levels in the sediment core show that there might not have been any more trees to burn for smelting metals. “One of the main conclusions we can draw is that when a particular area’s development explodes on a big scale, it ends up destroying itself,” he says.
PAUL CRADDOCK, THE RETIRED HEAD OF THE METALS SECTION at the British Museum’s Department of Scientific Research, remembers digging at Riotinto back in the 1970s and ’80s. “It was a full working mine, with the Electrohaul dumper trucks crashing past every few moments,” he says. “We had to be off the site most days by about 1 o’clock because they were blasting.”
Nowadays, Riotinto is a quieter place. The regional population has fallen from 42,000 in 1910 to 18,000 today. But the crash of trucks might return: Cyprus-based EMED Mining has bought the mines and hopes to reopen them in 2011. EMED says it’s working to preserve 12 historic sites, and plans to open some of them to the public.
Whether or not mining resumes, Delgado considers his museum—part of a larger mining park run by the Rio Tinto Foundation—as key to a new economic-development strategy. “This is another side of archaeology: to spread the knowledge of the ancient world and try to improve the conditions of people living in the present time,” he says. “If one is unable to accomplish those two goals, what is it worth to have a museum full of archaeological pieces?”
Delgado knows that not all his relatives have embraced his career choice. His wife would rather he took more vacation time at the beach, rather than running off to an excavation site with Pérez. As for Delgado’s maternal grandfather, who died two years ago: “My grandfather always used to say that he worked really hard so that his children and grandchildren would never have to work in the mine. Then I went to the university to end up in excavations with a pick and a shovel. He never understood that.”
Why did the Roman government stopped coining in silver?
The Roman government stopped coining in silver because the Spanish silver mine became empty, thus causing dearth of silver in the Roman empire. Now the Roman government began to use gold for the production of coinage.
Aug 15, 2023
What was the richest source of silver in the world?
The Cerro Rico de Potosí was the richest source of silver in the history of mankind. The extraction of mineral ores in Cerro Rico de Potosí began in 1545 by the Spanish Empire. Between the 16th and 18th century, 80% of the world's silver supply came out of this mine.
Las Médulas became the largest open pit gold mine excavated in the entirety of the Roman Empire's history. Its figures are overwhelming: an extension that exceeds 1,200 acres, reaching nearly two miles in width.
Jan 6, 2023
What is the meaning of Las Medulas?
Las Médulas isa Roman mining area located in the Autonomous community of Castile and León, in a mountainous zone in the Northwest of Spain. In the 1st century AD, the Roman Imperial authorities began to exploit the gold deposits of this region, using a technique based on hydraulic power.
Who created Las Medulas?
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. The technique employed was a type of hydraulic mining which involved undermining a mountain with large quantities of water.
Where did Rome get its gold?
Once the Romans conquered Spain, they mined gold in the Aduar Basin, Malaga District, the Plains of Granada, and the slopes of the Sierra Nevada mountains. Traces of gold in these regions can be found to date. Another large source came with Julius Caesar's conquest of Britain.
Mar 28, 2021
Las Médulas
Las Médulas
In the 1st century A.D. the Roman Imperial authorities began to exploit the gold deposits of this region in north-west Spain, using a technique based on hydraulic power. After two centuries of working the deposits, the Romans withdrew, leaving a devastated landscape. Since there was no subsequent industrial activity, the dramatic traces of this remarkable ancient technology are visible everywhere as sheer faces in the mountainsides and the vast areas of tailings, now used for agriculture.
Las Médulas is a Roman mining area located in the Autonomous community of Castile and León, in a mountainous zone in the Northwest of Spain. In the 1st century AD, the Roman Imperial authorities began to exploit the gold deposits of this region, using a technique based on hydraulic power. After two centuries of working the deposits, the Romans withdrew, leaving a devastated landscape. Since there was no subsequent industrial activity, the dramatic traces of this remarkable ancient technology are visible everywhere as sheer faces in the mountainsides and vast areas of tailings, now used for agriculture.
The area inscribed on the World Heritage List, the Archaeological Zone of Las Médulas, covers over 2000 ha. It comprises the mines themselves and also large areas covered by the tailings resulting from the process. There are dams which used to collect the vast amounts of water needed for the mining process and intricate canals through which the water was conveyed to the mines.
There are villages of both the indigenous inhabitants and the Imperial administrative and support personnel (including army units), as well as one major Roman road and a large number of minor routes, used during mining operations. The mining process, known to Pliny as ruina montium, made use of the immense power of large bodies of water. Water from springs, rain and melting snow was collected in large reservoirs, connected to the mines by a system of well-built gravity canals over long distances. They were cut into the sterile strata, many metres deep, over the layers of auriferous conglomerate. When the sluices of the dams were opened, enormous quantities of water flowed into the canals, which were closed at their ends. The pressure thus built up caused the rock to explode and be washed away by the water, forming enormous areas of tailings, several kilometres in length. The process is vividly apparent on the working face at the main Las Médulas site, where the half-sections of the galleries used for the last operation there stand out against the sheer rock face. The layers of the auriferous conglomerate were broken up in the same way, but the friable conglomerate was run through washing channels, the heavy gold particles falling to the bottom of the channels. The non-metallic part escaped to the layers of sterile tailings. The large boulders resulting from this process were removed by hand, as the neat heaps scattered around the landscape demonstrate.
The operating face of this spectacular mining process slowly moved across the landscape. The main Las Médulas pit covers more than 10 km2 and the working face on the subsidiary La Frisga pit is more than 600 m across. The system of water canals and conduits extended for at least 100 km. Contours were used with great skill to maintain even gradients over long distances so as to provide a steady build-up of water when the sluices were opened. These channels, short sections of which have been cleared, can be seen in many parts of the site. Archaeological survey over many years, both on the ground and using aerial observation and photography, has identified a number of settlements within the area. A selected group has been partially excavated and demonstrates the essential differences between the way of life of the indigenous and of the incoming administrative communities.
Criterion (i): Las Médulas is a major work of human creative genius in the field of mining, and specifically the technology of ruina montium, the application of water power, and systems of gold mining on a scale, efficiency, and economic importance that were of decisive economic importance for the Roman Empire in the first two centuries AD.
Criterion (ii): Las Médulas is a remarkable example of the application of Roman mining techniques to exploit precious metals. It is exceptional that subsequent works, which have largely destroyed such evidence elsewhere, were here limited or non-existent, so that this property is unquestionably the best preserved and most representative of all the mining areas of the Greco-Roman world in classical times.
Criterion (iii): The Roman gold-mining operations in the Las Médulas area were the most extensive ones in Antiquity. The spectacular remains illustrate both the remarkable technology and the administration of this Imperial estate in every detail.
Criterion (iv): The Las Médulas gold-mining area is an outstanding example of innovative Roman technology, in which all the elements of the ancient landscape, both industrial and domestic, have survived to an exceptional degree.
Integrity
Las Médulas has all the necessary elements to express its Outstanding Universal Value, since it includes the Roman mines, large areas where the tailings resulting from the process were deposited, the hydraulic canals used in the process of ruina montium and human settlements related to the mining work.
Las Médulas, due to its location on a rural area, with small communities, shows no negative effects of development.
Authenticity
The authenticity of the property is absolute, since no changes have been made to the Roman installations and deposits since they went out of use in the early 3rd century AD. The landscape of this area was formed by the extensive Roman mining operations. It was subsequently settled by small farming communities. This pattern endured until comparatively recently, when the area experienced the drift from the countryside to the towns that characterizes most of Europe. It has therefore conserved an organic landscape that has changed very little over many centuries. No changes have been made to the Roman installations and deposits since they went out of use in the early 3rd century AD.
Protection and management requirements
The Archaeological Zone of Las Médulas was registered as Bien de Interés Cultural (Property of Cultural Interest) in 1998, which means that this property is legally protected at the highest level; the zone was extended in 2007, in order to include all the World Heritage protected area. Furthermore, Las Médulas was declared a Historic Monument in 1931, and a Natural Monument in 2002. It is set under the responsibility of the Junta of Castile and León, through the General Directorate of Cultural Heritage.
Any intervention in this site, including archaeological investigation, therefore requires previous administrative authorization, according to the current Cultural Heritage Laws (Law 12/2002 of 11 July, of Cultural Heritage of Castile and León, Decree 37/2007 of 19 April, that approves the Rules for the Protection of Cultural Heritage in Castile and León and Law 16/1985, of 25 June, of Spanish Historic Heritage). All projects concerning this site must be previously approved by the Commission for Cultural Heritage of Castile and León.
Las Médulas is a Natural Monument, so it is also subject to the current Environmental Laws.
The municipalities of Borrenes, Carucedo and Puente de Domingo Flórez have an overall supervisory function in respect of the privately owned properties within their territories. Other institutions working in the area are the Las Médulas Foundation, which collaborates in the promotion of the site (Visitors Centre), and the Consejo Superior de Investigaciones Científicas, which has been leading an archaeological research program for several years and elaborated in 2001, commissioned by the Junta of Castile and León, the first Plan of Organization, Use and Management of Las Médulas.
Las Médulas, besides its declaration as National Monument and Property of Cultural Interest (Bien de Interés Cultural), has been registered as a “Cultural Area” (Espacio Cultural) in 2010. This protection is based on the Law of Cultural Heritage of Castile and León and is applied to those properties that have been already declared Bien de Interés Cultural which, due to their special natural and cultural values, request a preferential attention in their management and promotion. This declaration of “Cultural Area” aims at promoting the cultural and natural values of the site and encouraging all the activities leading to the sustainable development of the area. Its area is larger than that protected by the World Heritage Convention, because it includes the valley surrounding the site and the whole network of canals, aiming at controlling possible negative visual effects on Las Médulas.
For the adequate management of the “Cultural Area”, a Plan has been prepared, with the participation of local communities, the archaeological research team and the assessment of experts, to set the rules referring to protection, conservation, promotion and research, not only for the Archaeological Zone, but also for the World Heritage property. It is a roadmap that sets all the principles and features that the public administrations -at national, regional and local level- must take into account, in order to adapt their policies to the conservation of the Outstanding Universal Value of the site, which must prevail over other considerations. It includes a diagnosis of the state of conservation on the site, its cultural properties (archaeological sites, vernacular architecture, etc.) and the natural ones; and all the criteria to manage the World Heritage property (delimitation of the protected area; archaeological research; visits, accessibility and transport; principles for the urban planning; creation of a management organ which includes all the public administrations, experts and associations, etc.).
How Earth processes concentrated the precious metal that played a critical role in the history of Spain and Portugal
Figure 1. Las Médulas (León, NW Spain). This UNESCO World Heritage landscape is an ancient gold mine from Roman times. Photo courtesy of Bernardo López Santamaría
Restoring The 11th Century Temples of Bagan (Videos)
Myanmar's ambitious endeavor to secure UNESCO World Heritage status for the 11th-century temples of Bagan signals a significant commitment to preserving this invaluable cultural heritage site. Ravaged by an earthquake and subjected to ill-conceived restoration efforts in the past, these ancient temples are in dire need of careful and meticulous restoration. The history enshrined within Bagan's temples is irreplaceable, with their stunning architectural grandeur and spiritual significance drawing visitors from across the globe. However, the earthquake damage and prior hasty renovations have posed serious threats to their integrity.
Myanmar's current restoration plans demonstrate a more thoughtful approach. By seeking UNESCO's recognition, they are not only acknowledging Bagan's global significance but also pledging to uphold international conservation standards. This effort must prioritize authenticity over haste, ensuring that the temples retain their historical character. With an eye toward careful restoration, Myanmar aspires to breathe new life into these ancient structures while preserving their historical essence. As this endeavor unfolds, it holds the promise of not just restoring temples but also safeguarding a living record of human history for generations to come.
Does Puebla, Cholula and several more Mesoamerican structures have any more tunnels and chambers to be found? I'm sure there are more waiting to be discovered considering that several have only been partially excavated so far. The large structures themselves are not completely solid inside and underneath. They have several tunnel access and large rooms or chambers and Archaeologist are busy digging up several more at the moment. Hopefully one day they will be open to the public to see and visit.
The videos shown below have tunnels that's been recently open to the public. These sites attract a lot of tourist annually.
Exploring SECRET UNDERGROUND TUNNELS in Puebla ...
