Last updated Map of the mines and resources in Roman Britain.
Mining was one of the most prosperous activities in Roman Britain. Britain was rich in resources such as copper, gold, iron, lead, salt, silver, and tin, materials in high demand in the Roman Empire. Sufficient supply of metals was needed to fulfil the demand for coinage and luxury artefacts by the elite.[1] The Romans started panning and puddling for gold. The abundance of mineral resources in the British Isles was probably one of the reasons for the Roman conquest of Britain. They were able to use advanced technology to find, develop and extract valuable minerals on a scale unequaled until the Middle Ages.
Lead was essential to the smooth running of the Roman Empire.[2] It was used for piping for aqueducts and plumbing, pewter, coffins, and gutters for villas, as well as a source of the silver that sometimes occurred in the same mineral deposits. Fifty-two sheets of Mendip lead still line the great bath at Bath which is a few miles from Charterhouse (see below).
The largest Roman lead mines were located in or near the Rio Tinto (river) in southern Hispania.[3][4] In Britannia the largest sources were at Mendip, South West England and especially at Charterhouse. In A.D. 49, six years after the invasion and conquest of Britain, the Romans had the lead mines of Mendip and those of Derbyshire, Shropshire, Yorkshire and Wales running at full shift. By A.D.70, Britain had surpassed Hispania as the leading lead-producing province. The Spanish soon lodged a complaint with the Emperor Vespasian, who in turn put limits on the amount of lead being produced in Britain. However British lead production continued to increase and ingots (or pigs) of lead have been found datable to the late second - early third century.[5] Research has found that British lead (i.e. Somerset lead) was used in Pompeii - the town destroyed in the eruption of Vesuvius in A.D.79.
The Romans mined lead from the Mendips, Derbyshire, Durham, and Northumberland.[6] The silver content of ores from these areas was significantly lower than Athenian lead-silver mines and Asia Minor mines.[6]
Smelting is used to convert lead into its purest form. The extraction of lead occurs in a double decomposition reaction as the components of galena are decomposed to create lead.[6] Sulfide is the reducing agent in this reaction, and fuel is only needed for high temperature maintenance. Lead must first be converted to its oxide form by roasting below 800C using domestic fire, charcoal or dry wood.[6] This is done easily as lead melts at 327C. Lead oxide (PbO) is the oxide form of galena which reacts with the unroasted form lead sulfide (PbS) to form lead (Pb) and sulfur dioxide (SO2).[6]
Details on Roman lead smelting have not been published even though open hearths were found in the Mendips by Rahtz and Boon.[6] These remains contained smelted and unsmelted ores.[6] The remains of first-century smelting were found in Pentre, Ffwrndan. Although this discovery was valuable, reconstruction of the remains were impossible due to damage.[6] An extracted ore from the site had a lead content of 3 oz. (5 dwt) per ton and another piece contained 9 oz. (16 dwt) per ton of lead.[6]
Silver extraction
The most important use of lead was the extraction of silver. Lead and silver were often found together in the form of galena, an abundant lead ore. Galena is mined in the form of cubes and concentrated by removing the ore-bearing rocks.[6] It is often recognized by its high density and dark colour.[6] The Roman economy was based on silver, as the majority of higher value coins were minted from the precious metal. British ores found in Laurion, Greece had a low silver content compared to the ores mined from other locations.[6] The Romans used the term 'British silver' for these lead mines.[6]
Galena was mined for its lead and silver content.
The process of extraction, cupellation, was fairly simple. First, the ore was smelted until the lead, which contained the silver, separated from the rock. The lead was removed, and further heated up to 1100° Celsius using hand bellows. At this point, the silver was separated from the lead (the lead, in the form of litharge, was either blown off the molten surface or absorbed into bone ash crucibles; the litharge was re-smelted to recover the lead), and was put into moulds which, when cooled, would form ingots that were to be sent all over the Roman Empire for minting.[2][7] Silchester, Wroxeter, and Hengisbury Head were known locations for Roman cupellation remains.[6]
When inflation took hold in the third century A.D. and official coins began to be minted made of bronze with a silver wash, two counterfeit mints appeared in Somerset - one on the Polden Hills just south of the Mendips, and the other at Whitchurch, Bristol to the north. These mints, using Mendip silver, produced coins which were superior in silver content to those issued by the official Empire mints. Samples of these coins and of their moulds can be seen in the Museum of Somerset in Taunton Castle.
Copper mining
Copper alloy was mostly utilized in Roman Britain to make brooches, spoons, coins, statuettes and other things needed for armour.[8] It was rarely used in it purest form; thus, it always contained other elements such as tin, zinc or lead, which added various properties to the alloy.[8] Pure copper has a pinkish colour and, with the addition of a few percentage of other elements, its colour may change to pale brown, white or yellow.[8]
The composition of copper alloy differed from region to region in the Roman Empire.[9] Leaded and unleaded bronze were mainly used in the Mediterranean period.[9] These types of bronze were produced by adding tin and lead to copper in certain amounts that depended on the type of object being produced.[9] 5% to 15% of tin was added to bronze for casting of most objects. Mirrors, on the other hand, were made with bronze that had approximately 20% tin as it needed a speculum, which is a silvery-white alloy.[9]
Another copper alloy, brass, was not widely used in casting objects as it was very difficult to produce.[9] The production of brass did not begin until the development of the cementation process.[9] In this process, zinc ore and pure copper are heated in a sealed crucible.[9] As the zinc ore is turned into zinc, the seal in the crucible traps the zinc vapour inside, which will then mix with the pure copper to produce brass.[9] The production of brass through this process was controlled by 'state monopoly' as brass was being utilized for coins and military equipments.[9] The production of sestertii and dupondii from brass was established by the Augustan period and brass was also utilized in production of other military fittings such as lorica segmentata.[9]
Gold was mined in Linlithgow (Scotland), Cornwall (England), and other British Isles locations.[citation needed] Melting was necessary for this form of native silver as it is found in a form of leaves or filaments.[citation needed]
Britain's gold mines were located in Wales at Dolaucothi. The Romans discovered the Dolaucothi vein soon after their invasion, and they used hydraulic mining methods to prospect the hillsides before discovering rich veins of gold-bearing quartzite. The remains of several aqueducts and water tanks above the mine are still visible today. The tanks were used to hold water for hushing during prospecting for veins, and involved releasing a wave of water to scour the ground and remove overburden, and expose the bedrock. If a vein was found, then it would be attacked using fire-setting, a method which involved building a fire against the rock. When the hot rock was quenched with water, it could be broken up easily, and the barren debris swept away using another wave of water. The technique produced numerous opencasts which are still visible in the hills above Pumsaint or Luentinum today. A fort, settlement and bath-house were set up nearby in the Cothi Valley. The methods were probably used elsewhere for lead and tin mining, and indeed, were used widely before explosives made them redundant. Hydraulic mining is however, still used for the extraction of alluvial tin.
Long drainage adits were dug into one of the hills at Dolaucothi, after opencast mining methods were no longer effective. Once the ore was removed, it would be crushed by heavy hammers, probably automated by a water wheel until reduced to a fine dust. Then, the dust would be washed in a stream of water where the rocks and other debris would be removed, the gold dust and flakes collected, and smelted into ingots. The ingots would be sent all across the Roman world, where they would be minted or put into vaults.[2]
Iron mining
Armour, construction tools, agricultural tools, and other building materials were mostly made of iron; thus, making iron one of the most in demand metals at all times.[1] There was always a supply for iron in many parts of the Roman Empire to allow for self sufficiency.
There were many iron mines in Roman Britain. The index to the Ordnance Survey Map of Roman Britain lists 33 iron mines: 67% of these are in the Weald and 15% in the Forest of Dean. Because iron ores were widespread and iron was relatively cheap, the location of iron mines was often determined by the availability of wood, which Britain had in abundance, to make charcoal smelting fuel. Great amounts of iron were needed for the Roman war machine, and Britain was the perfect place to fill that need.[10]
Many underground mines were constructed by the Romans. Once the raw ore was removed from the mine, it would be crushed, then washed. The less dense rock would wash away, leaving behind the iron oxide, which would then be smelted with the bloomery method. Mixed with charcoal, the iron ore was heated in a low furnace below the melting point to avoid creating pig iron, and to allow the reduced iron to agglomerate in a Play-Doh like state. The slag was taped out and disposed in very large quantities, allowing easy identification of the sites by archeologists, and sometimes used as road construction material. The extracted bloom iron was roughly hammered and probably sold as is to forges for further refining and use.[10]
Roman iron was thought to hold more value than other metals due to the tedious production through direct or bloomery smelting.[11] A recovered Vindolanda tablet documents the purchase of 90 Roman pounds of iron for 32 denarii by a man named Ascanius.[11] This amounted to 1.1 denarii per kilogram of iron.[11]
Coal
For both domestic and industrial use, coal provided a considerable proportion of the fuel required for warmth, metal-working (coal was not suitable for the smelting of iron, but was more efficient than charcoal at the forging stage)[12] and the production of bricks, tiles and pottery. This is demonstrated by archaeological evidence from sites as far apart as Bath, Somerset (the temple of Sulis and household hypocausts), military encampments along Hadrian's wall (where outcrop coal was worked near the outlying fortlet at Moresby), forts of the Antonine Wall, Carmel lead mines in north Wales and tile kilns at Holt, Clwyd. Excavations at the inland port of Heronbridge on the River Dee show that there was an established distribution network in place. Coal from the East Midlands coalfields was carried along the Car Dyke for use in forges to the north of Duroliponte (Cambridge) and for drying grain from this rich cereal-growing region.[13][14][15][16] Extraction was not limited to open-cast exploitation of outcrops near the surface: shafts were dug and coal was hewn from horizontal galleries following the coal seams.[17]
Some miners may have been slaves, but skilled artisans were needed for building aqueducts and leats as well as the machinery needed to dewater mines and to crush and separate the ore from barren rock. Reverse overshot water-wheels were used to lift water, and sequences of such wheels have been found in the Spanish mines. A large section of a wheel from Rio Tinto can be seen in the British Museum, and a smaller fragment of a wheel found at Dolaucothi shows they used similar methods in Britain.
The working conditions were poor, especially when using fire-setting under ground, an ancient mining method used before explosives became common. It involved building a fire against a hard rock face, then quenching the hot rock with water, so that the thermal shock cracked the rock and allowed the minerals to be extracted. The method is described by Diodorus Siculus when he discussed the gold mines of Ancient Egypt in the first century BC, and at a much later date by Georg Agricola in his De Re Metallica of the 16th century. Every attempt was made to ventilate the deep mines, by driving many long adits for example, so as to ensure adequate air circulation. The same adits also served to drain the workings.
Fall of the metal economy
The Roman economy depended on the abundant metals that were mined in many regions.[18] Approximately 100,000 tons of lead and 15,000 tons of copper were sourced within the imperial territory and about 2,250 tons of iron were produced each year.[18] This abundance and extensive production of metal contributed to the pollution in Greenland ice, and it also affected the metal industry as more and more inexpensive metals were available throughout the empire.[18]
The production and availability of smelted metal started to cease during the late fourth century as the Romano-British economy began to decline.[18] The only solution for people who needed metals as part of their livelihood was to scavenge for metal scraps.[18] This is evident from the excavated metalworks from Southwark and Ickham.[18] By the end of fourth century Britain was unable to sustain the need for metals, and so many metal-working sites were abandoned and skilled workers were left with no jobs.[18]
↑ Rosman, Kevin J. R.; Chisholm, Warrick; Hong, Sungmin; Candelone, Jean-Pierre; Boutron, Claude F. (December 1997). "Lead from Carthaginian and Roman Spanish Mines Isotopically Identified in Greenland Ice Dated from 600 B.C. to 300 A.D.". Environmental Science & Technology. 31 (12): 3413–3416. doi:10.1021/es970038k. INIST2099549.
↑ Sim, David (1 June 2012). "Overview of the technical aspects of iron making". The Roman Iron Industry in Britain. Stroud, UK: The History Press. ISBN9780752468655.
↑ Forbes, R.J. (1958). Studies in ancient Technology. Vol.VI. Leiden, Netherlands: Brill. p.27. OCLC848445642.
↑ Clark, J. G. D. (October 1949). "Report on Excavations on the Cambridgeshire Car Dyke, 1947". The Antiquaries Journal. 29 (3–4): 145–163. doi:10.1017/S0003581500017261. S2CID162382017.
Brass is an alloy of copper (Cu) and zinc (Zn), in proportions which can be varied to achieve different colours and mechanical, electrical, acoustic, and chemical properties, but copper typically has the larger proportion. In use since prehistoric times, it is a substitutional alloy: atoms of the two constituents may replace each other within the same crystal structure.
Mining is the extraction of valuable geological materials and minerals from the surface of the Earth. Mining is required to obtain most materials that cannot be grown through agricultural processes, or feasibly created artificially in a laboratory or factory. Ores recovered by mining include metals, coal, oil shale, gemstones, limestone, chalk, dimension stone, rock salt, potash, gravel, and clay. The ore must be a rock or mineral that contains valuable constituent, can be extracted or mined and sold for profit. Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even water.
An ingot is a piece of relatively pure material, usually metal, that is cast into a shape suitable for further processing. In steelmaking, it is the first step among semi-finished casting products. Ingots usually require a second procedure of shaping, such as cold/hot working, cutting, or milling to produce a useful final product. Non-metallic and semiconductor materials prepared in bulk form may also be referred to as ingots, particularly when cast by mold based methods. Precious metal ingots can be used as currency, or as a currency reserve, as with gold bars.
William Humfrey (c.1515–1579) was an English goldsmith, mining promoter, and Assay Master at the Royal Mint during the reign of Elizabeth I.
The Dolaucothi Gold Mines, also known as the Ogofau Gold Mine, are ancient Roman surface and underground mines located in the valley of the River Cothi, near Pumsaint, Carmarthenshire, Wales. The gold mines are located within the Dolaucothi Estate, which is owned by the National Trust.
Pumsaint is a village in Carmarthenshire, Wales, halfway between Llanwrda and Lampeter on the A482 in the valley of the Afon Cothi. It forms part of the extensive estate of Dolaucothi, which is owned by the National Trust.
The history of metallurgy in the Indian subcontinent began prior to the 3rd millennium BCE. Metals and related concepts were mentioned in various early Vedic age texts. The Rigveda already uses the Sanskrit term ayas. The Indian cultural and commercial contacts with the Near East and the Greco-Roman world enabled an exchange of metallurgic sciences. The advent of the Mughals further improved the established tradition of metallurgy and metal working in India. During the period of British rule in India, the metalworking industry in India stagnated due to various colonial policies, though efforts by industrialists led to the industry's revival during the 19th century.
The ancient Romans were famous for their advanced engineering accomplishments. Technology for bringing running water into cities was developed in the east, but transformed by the Romans into a technology inconceivable in Greece. The architecture used in Rome was strongly influenced by Greek and Etruscan sources.
A stamp mill is a type of mill machine that crushes material by pounding rather than grinding, either for further processing or for extraction of metallic ores. Breaking material down is a type of unit operation.
Silver mining is the extraction of silver from minerals, starting with mining. Because silver is often found in intimate combination with other metals, its extraction requires elaborate technologies. In 2008, ca. 25,900 metric tons were consumed worldwide, most of which came from mining.
The technology history of the Roman military covers the development of and application of technologies for use in the armies and navies of Rome from the Roman Republic to the fall of the Western Roman Empire. The rise of Hellenism and the Roman Republic are generally seen as signalling the end of the Iron Age in the Mediterranean. Roman iron-working was enhanced by a process known as carburization. The Romans used the better properties in their armaments, and the 1,300 years of Roman military technology saw radical changes. The Roman armies of the early empire were much better equipped than early republican armies. Metals used for arms and armor primarily included iron, bronze, and brass. For construction, the army used wood, earth, and stone. The later use of concrete in architecture was widely mirrored in Roman military technology, especially in the application of a military workforce to civilian construction projects.
Charterhouse was a town in the Roman province of Britannia. Its site is located just to the west of the village of Charterhouse-on-Mendip in the English county of Somerset.
Mining in Wales provided a significant source of income to the economy of Wales throughout the nineteenth century and early to mid twentieth century. It was key to the Industrial Revolution in Wales, and to the whole of Great Britain.
Hushing is an ancient and historic mining method using a flood or torrent of water to reveal mineral veins. The method was applied in several ways, both in prospecting for ores, and for their exploitation. Mineral veins are often hidden below soil and sub-soil, which must be stripped away to discover the ore veins. A flood of water is very effective in moving soil as well as working the ore deposits when combined with other methods such as fire-setting.
The following outline is provided as an overview of and topical guide to mining:
Mining archaeology is a specific field well-developed in the British Isles during recent decades. A reason of ongoing interest in this field is the particular bond between regional history and the exploitation of metals. References to mines in the area exist in Strabo's works. However the first accomplished study on the topic was attempted by Oliver Davies in 1935. Other momentous researches were that of geologist John S. Jackson about mines in Ireland and Lewis, Jones in Dolaucothi goldmine in Wales, and the pioneering work of Ronald F. Tylecote. Moreover, in the 1980s and 1990s a new generation of amateurs and scientists began investigations in different locations in the British Isles, including Duncan James on the Great Orme's Head, Simon Timberlake with the Early Mines Research Group at sites in Wales and William O'Brien in Ireland.
Metals and metal working had been known to the people of modern Italy since the Bronze Age. By 53 BC, Rome had expanded to control an immense expanse of the Mediterranean. This included Italy and its islands, Spain, Macedonia, Africa, Asia Minor, Syria and Greece; by the end of the Emperor Trajan's reign, the Roman Empire had grown further to encompass parts of Britain, Egypt, all of modern Germany west of the Rhine, Dacia, Noricum, Judea, Armenia, Illyria, and Thrace. As the empire grew, so did its need for metals.
Mining in the United Kingdom produces a wide variety of fossil fuels, metals, and industrial minerals due to its complex geology. In 2013, there were over 2,000 active mines, quarries, and offshore drilling sites on the continental land mass of the United Kingdom producing £34bn of minerals and employing 36,000 people.
Plants for the production of lead are generally referred to as lead smelters. Primary lead production begins with sintering. Concentrated lead ore is fed into a sintering machine with iron, silica, limestone fluxes, coke, soda ash, pyrite, zinc, caustics or pollution control particulates. Smelting uses suitable reducing substances that will combine with those oxidizing elements to free the metal. Reduction is the final, high-temperature step in smelting. It is here that the oxide becomes the elemental metal. A reducing environment pulls the final oxygen atoms from the raw metal.
Non-ferrous extractive metallurgy is one of the two branches of extractive metallurgy which pertains to the processes of reducing valuable, non-iron metals from ores or raw material. Metals like zinc, copper, lead, aluminium as well as rare and noble metals are of particular interest in this field, while the more common metal, iron, is considered a major impurity. Like ferrous extraction, non-ferrous extraction primarily focuses on the economic optimization of extraction processes in separating qualitatively and quantitatively marketable metals from its impurities (gangue).
References
Davies, O, Roman Mines in Europe, Oxford (1935).
Elkington H.D.H.The Mendip Lead Industry in Branigan K. and Fowler P.J. The Roman West Country (1976)
Elkington H.D.H. The Development of the Mining of Lead in the Iberian Peninsula and Britain under the Roman Empire. Durham University Library (1968)
Jones G. D. B., I. J. Blakey, and E. C. F. MacPherson, Dolaucothi: the Roman aqueduct, Bulletin of the Board of Celtic Studies 19 (1960): 71-84 and plates III-V.
Lewis, P. R. and G. D. B. Jones, The Dolaucothi gold mines, I: the surface evidence, The Antiquaries Journal, 49, no. 2 (1969): 244–72.
Lewis, P. R. and G. D. B. Jones, Roman gold-mining in north-west Spain, Journal of Roman Studies 60 (1970): 169–85.
Jones, R. F. J. and Bird, D. G., Roman gold-mining in north-west Spain, II: Workings on the Rio Duerna, Journal of Roman Studies 62 (1972): 59–74.
Lewis, P. R., The Ogofau Roman gold mines at Dolaucothi, The National Trust Year Book 1976-77 (1977).
Annels, A and Burnham, BC, The Dolaucothi Gold Mines, University of Wales, Cardiff, 3rd Ed (1995).
Burnham, Barry C. "Roman Mining at Dolaucothi: the Implications of the 1991-3 Excavations near the Carreg Pumsaint", Britannia28 (1997), 325-336
Hodge, A.T. (2001). Roman Aqueducts & Water Supply, 2nd ed. London: Duckworth.
Burnham, BC and H, Dolaucothi-Pumsaint: Survey and Excavation at a Roman Gold-mining complex (1987-1999), Oxbow Books (2004).
Further reading
Dark, K., and P. Dark. The landscape of Roman Britain. Stroud: Sutton, 1997.
Jones, B., and D. Mattingly. An atlas of Roman Britain. Oxford: Oxbow, 2002.
Reece, R. The coinage of Roman Britain. Stroud: Tempus, 2002.
Schrüfer-Kolb, Irene. Roman Iron Production In Britain: Technological and Socio-Economic Landscape Development Along the Jurassic Ridge. Oxford: Archaeopress, 2004.
Sim, D., and I. Ridge. Iron for the eagles: The iron industry of Roman Britain. Stroud: Tempus, 2002.
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