Dr Robert Sturm (Austria)
Ancient civilizations had a high demand for raw materials, like clay, diverse rocks and, most of all, metals. These were required for buildings, crafts, agriculture, their armed forces, financial concerns, art and culture. Clays and rocks produced by opencast mining primarily served for the production of bricks and building blocks, which were used for civil and hydraulic engineering. They were additionally extracted for the manufacture of durable goods and art objects, such as dishes and statues. Metals – like gold, silver, copper, tin, iron and lead – being essential raw materials in antique civilisations, were commonly produced by underground mining. Gold and silver were mostly used as raw material for ancient coins.
The use of noble metals in monetary economy has been going on since the seventh century BC, when barter trade was successively replaced by a monetary economy. Copper, tin and iron was mostly produced for the manufacture of arms, whereas lead was, among other things, used for the production of water conduits and as a stain for ornamental painting.
Ancient techniques used for the mining of raw materials
Sufficient supplies of metallic and mineral raw materials required systematic mining, since only gold was found in large enough amounts in washes of brooks and rivers to make panning worthwhile. Other metals usually occurred as chemical components of ore minerals, which were found in regionally varying concentrations in loads and stocks. According to Pliny (Naturalis Historiae XXXIII, 67) and Seneca (Beneficiis IV, 6, 1), recognition of ore deposits was made possible by proofing properties of the soils that superimposed the deposits.
Then, where the ore loads and stocks cropped out, raw materials could be produced by opencast mining, using special tools for exploiting or cutting the rocks and high-temperature furnaces for separating valuable minerals from the ores. On the other hand, if the ore deposits were positioned deep below the earth surface, exploitation of the raw materials could take place only by underground mining.
In ancient Greek culture, deep mining primarily took place through the construction of underground galleries, within which the crushed ore was washed and subsequently prepared for smelting. This stage of dressing was conducted by using washing tables, which still exist in places at their original sites. The rainwater needed for the process was held in cisterns and collected during winter months.
The extraction of copper and tin, and the production of bronze, being an alloy of both metals (90% Cu, 10% Sn), already dated back to the third millennium BC and was established on Cyprus. Iron metallurgy had been carried out since the fifteenth century BC and had become the main military material in the first millennium BC. At this time, Greek mining, with its specific techniques, did not change remarkably and some mines, like that on the Lavrion (in modern day Greece; see below), were exploited over a time span of several hundred years.
As far as the effective application of mining techniques is concerned, the Romans proved to be docile disciples of the Greeks, Egyptians and Iberians, whose methods of systematic underground mining were taken over and considerably refined. The mining of raw materials was commonly carried out with the help of hammers, chisels, small baskets, wooden troughs and sacks made of leather. According to the well-known Roman author, Vitruvius (De Architectura Libri Decem X, 3), for vertical transport of the minerals and ores towards the surface, Romans used a special winch termed sucula. Lighting of the mining tunnels was achieved by oval clay lamps, whose burning-time was a measure for the working time for slaves. Supply of fresh air to the adits and galleries was guaranteed by the digging of parallel and side pits enabling a natural draught. Where necessary, the supply of fresh air was improved by the use of large fans made of fabric.
As one of the most remarkable technical solutions in ancient mining, the Romans developed specific machines and apparatuses for the drainage of the pits. Deep pits were commonly drained by the creation of small adits taking the water to deeper levels of the mine. If this drainage technique was not successful, water wheels and Archimedean screws were used to elevate the water. According to ancient literature, such bucket-wheels had a diameter of up to 4.5m and were driven by manpower. They were also able to lift the water by about 3.6m. Using Archimedean screw pumps, heights of between 1.5m and 2.5m could be surmounted.
Important mines in ancient Greece
In ancient Greece, early gold and silver mining was carried out on the island of Siphnos (Herodotus III, 57; Pausanias XI, 2), but the amount of noble metals hauled from the mines was rather low. A much higher output could be produced in the gold mines on the island of Thasos and on the island of Samothrace, south of the Thracian coast. Further gold mines were positioned in Thrace and Macedonia, and Macedonia was also well known for the occurrence of gold washes along the River Hebros (Pliny, Naturalis Historiae XXXVII, 66).
Among the ancient silver mines, those situated in the mountains of Lavrion on Attica gained the greatest glory. The exploitation of silver ores probably started in the fifteenth century BC, but reached its zenith between the seventh and fifth centuries BC, when a monetary economy successively replaced barter trade. Until the beginning of the fifth century BC, silver was mainly extracted through opencast mining, but, later on, underground mining became more and more important. This resulted in the production of about 2,000 shafts and adits with a total length of 140km. In the fifth century BC, between 10,000 and 30,000 miners worked in the silver mines of Lavrion, where slaves – representing the main body of workers – were assisted by poor day-labourers.
Copper mines were, among other mines, situated on the island of Delos and also in Eretria. The greatest abundance of iron ore was found in the Tagetos, on the island of Euboea, and also in the mountains of Lavrion. Among the Cycladic islands, Andros and Syros also had abundant iron deposits. They were only exceeded by the island of Seriphos (Serpho), where mining resulted in the achievement of enormous wealth and has been carried out until modern times.
Roman raw materials
In the Roman Empire, mining was instrumental for both the military and the economy in general. Gold, silver, iron and bronze were made into coins, armour and arms. From classical to late antiquity, numerous mining areas were located in every colony of the empire. Centres of ancient mining included Attica, the gold mines of Nubia in Spain, and the tin mines of Cornwall and Devon in Great Britain.
However, the Italian peninsula itself was not abundant with raw materials. Some silver was produced in Bruttium in southern Italy, and copper and iron were, among other metals, extracted in Massa Marittima in Populonia, and on the island of Elba. After the conquest of the Iberian Peninsula by the Romans, all copper, silver and gold resources found there became ‘treasure trove’ of the Roman Empire. In the second century BC, about 40,000 miners worked in the silver mines of Cartagena. In early times, mining was carried out by Romans themselves, but, later on, with the considerable expansion of the mining industry, foreign slaves, convicts and exiles also had to work in the pits.
In the first century AD, the Romans began to exploit the large alluvial gold deposits in Spain, with the largest site being located in Las Medulas. The gold was extracted by a mining technique known as ‘hushing’, where one or more aqueducts supplied water to the mine head, which was stored in huge reservoirs and cisterns. This water was used to sluice away the overburden and, as a result, to expose the bedrock and any gold veins present. The rock was subsequently heated by fires and then quenched with water, resulting in cracks in the rock and the possibility of removal of the gold. The last step consisted of smelting the ore.
The traces of ancient mining
In many places, extensive exploitation of the mining sites resulted in a destruction of the environment, which still determines today’s landscapes. Besides the archaeological remains of silver mining in Lavrion, huge spoil heaps and rubble have also been conserved over thousands of years and have prevented the growth of the prevailing rich Mediterranean vegetation. In Las Medulas, application of hushing required the production of numerous aqueducts and canals, the latter of which still pass through the today’s landscape.
Additionally, the landscape and ecosystems at the ancient sites have been subject to considerable transformation/re-structuring remodelling. A closer look at the mining site confirms what Pliny already termed a ruina montium (a wrecking of mountains). As mentioned in the introduction, lead was one of the mostly widely used metals in ancient Greece and Rome. Besides its application as a stain for sculptures and reliefs, lead was needed (or used) for the production of water conduits, drinking-vessels, cosmetics, medicine and food.
Any enhanced uptake of lead through food had dramatic consequences for the health of the people. Some physicians of ancient Greece already knew about the dangers of this heavy metal, but did not complain about its use. In addition, lead was also used as the raw material for metal clamps, which were used in the tight junctions of stone building blocks, some of which have been conserved until today. Air pollution by industry and traffic causes the lead to dissolve and it then seeps into the ground water, from where it may be taken up into the food cycle.
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