the Elder (23-79 AD)
Although the great Roman soldier and observer Pliny the Elder was not a mining man, his writings on mining operations that he visited across the Roman Empire, particularly Spain where he was a procurator responsible for mine administration, have created an invaluable record for posterity. The book in which they appear, Historia Naturalis, is in fact a comprehensive study of geography and nature in the Roman Empire, and the sections on metals and mining are just a small part of the work. However, they are one of the few sources of directly observed comments on mining techniques in the ancient world that have survived to this day.
Born Gaius Plinius Secundus in 23 AD in Como, northern Italy, Pliny’s family held equestrian status indicating that they had money and were deemed aristocrats or knights. Pliny received formal education in Rome where his tutor, Pomponius, who was one of Rome’s leading poets, provided Pliny with connections important to his future career. At the age of 21 he went to the Low Countries to serve as a military tribune, an administrative post, but soon became a military officer. For the next few years Pliny served in the Lower Rhine area where he saw active service under his old tutor Pomponius.
At this stage, around 50 AD, Pliny began to write books, which included a biography of Pomponius and a history of the Germanic Wars. He returned to Rome where he might have been expected to continue his career in public service. It was, however, the age of Nero and Pliny’s position as a serious historian did not fit into Nero’s increasingly debauched society. He wrote further books which did not attract positive comment and as Nero’s rule ended with the Emperor’s suicide, a vicious civil war broke out. Around that time Pliny’s brother-in-law died and Pliny took on the guardianship of his nephew Pliny the Younger.
Vespasian, whose son Titus was a great friend of Pliny’s, had taken up arms to press his claim to become emperor as the post-Nero situation became increasingly chaotic. Vespasian entered Rome as emperor in 69 AD and from that point on Pliny’s career took a major turn for the better as he assumed a number of important public posts as a procurator, which took him all over the Empire. One of the regions he visited was Spain, where his responsibilities included keeping an eye on the gold mines which had assumed a key role in the Empire’s finances. It was here that he made copious notes on the techniques of mining and treating gold at locations such as Las Medulas in Leon, observations which eventually were incorporated into the mining section of his Historia Naturalis. He was not remotely a gold bull, however, as he believed that it merely played on man’s natural greed. He also made observations about silver mining, base metal (including lead) mining and even diamonds. The Historia also contained sections covering the use of metals in what we would now call manufacturing.
Pliny’s career continued with his appointment as prefect for the Roman navy in the western Mediterranean and it was during this phase of his life that Historia Naturalis was completed and published in 77 AD. In August 79 AD Pliny was holidaying with his sister and Pliny the Younger in Misenum when Mount Vesuvius erupted. Pliny ordered a fleet of ships, which he commanded, to set sail to rescue those who had escaped the disaster and were gathered on the shore outside Pompeii. He, unfortunately, had to spend the night ashore and in the morning was found dead overcome by the sulphurous fumes from Vesuvius.
The only book of Pliny’s to have survived is Historia Naturalis. Whilst archaeologists have done much work on ancient mining sites around the world and in so doing have provided much useful information on mining construction and techniques, Pliny’s observations are the real thing. They reveal the relatively sophisticated mining methods of the Romans, including the use of hydraulic (water pressure) style mining 1700 years before it was introduced into 19th century mining. As such Pliny’s work holds an invaluable place in the study of the mining industry’s historic development.
The site today of the Las Medulas gold mine in Leon, Spain which was mined in Roman times from the first century AD
Source: Rafael Ibanez Fernandez
Rome’s Spanish mines
As well as gold, the Romans operated silver and lead mines around the same time in central Spain at Plasenzuela, Extremadura, for a period of around a hundred years. These mines do not appear to have been visited by Pliny so we must rely once more on the observations of archaeologists and the discoveries of the miners who operated the mines again in the second half of the 19th century. The dating of the Plasenzuela operations to Roman times relates to the toxicity of some of the residues on the site, which contain arsenic and come from smelting of the mine output, a sure sign of Roman involvement. Roman roof slate fragments were also found in the slag heaps. Investigation of some of the slag also suggested that the Romans had experimented with a process to try to recover some of the lead metal lost in the smelting process.
Much evidence has also been found of ancient mining in southwest Spain in Almeria in the Sierra Almagrera, which probably started in the 3rd millennium BC, and over the centuries carried out by a variety of visitors including the Phoenicians, the Romans and the Moors. The mines here produced lead and silver and though they were inactive for centuries during the Middle Ages they came back to life in the 19th century. Today mining is very small scale, carried out by individual entrepreneurial miners.
Another ancient mining site in Almeria was Rodalquila, where gold has been the target since Roman times. The Romans were also responsible for the development of the Ojos Negros iron mines in Teruel in the north of Spain, and of the giant mercury mines of Almeden Puertollano in Ciudad Real. Near Barcelona the mines of Gava were mined from around the 4th millennium BC for a green mineral called variscite that was probably used for making basic but colourful jewellery. Also from this period in Murcia in southeast Spain mining of iron, lead and zinc began and continued up until the 20th century.
Whilst Spain was both the Republic and the Empire’s most important provider of metals and minerals, Italy itself was a substantial source of raw materials, particularly of industrial minerals such as salt, stone and clay. Records are thin on Rome’s Italian mineral sources but according to Polybius rich gold deposits were found and worked at Aquileia at the top of the Adriatic, near what were to become the lagoons of Venice. The Republic also acquired the gold mines of the Alpine tribe, the Salassi, when they conquered the small territory which lies on the Italian side of the Alps in 138 BC. Sardinia, acquired by the Republic from Carthage in 238 BC, was also a substantial producer of silver, lead and iron ore.
Organisation of Roman mines
The Romans were an advanced and so very well organised society, a critical attribute for the efficient operation of an empire that lasted many centuries. They firmly believed in structure and mining was an area where they established, both at home and in the conquered territories, a legal structure to enable raw materials to be extracted and for the extraction process to yield tax and royalty revenues for the treasuries of the Empire. The richness of the Spanish gold and silver mines unfortunately led to bureaucratic corruption, although the flow of revenues to Rome meant that a blind eye was turned to official pocket lining.
The Romans developed two main administrative structures for mining. One consisted of a leasing system where Roman revenue officials auctioned mining leases to the highest bidder. Having leased the mines to operators, this bidder was then expected to provide Rome with an agreed flow of revenue from the mines. This revenue was obtained from the mine operators, very often the main lease owner making large amounts from the difference between what Rome expected in payments from him and what he charged the lease operator in royalties.
The other system was similar in terms of lease payments to Rome but the control of the mines was vested in an administrator appointed by Rome who either leased the properties to mine operators or himself took on the task of running the mines. There was plenty of room within this system for personal gain and the chicanery started at the top, with the Caesars in the late 1st century AD particularly rapacious as they took control of many of the Empire’s gold and silver mines. In due course, as the Empire began to collapse the mines deteriorated, corrupt practices