How Did Copper Mining Evolve in Bronze Age Britain?

From around the third millennium BC (5000 years ago), people in Iberia began exploiting sources of copper among other raw materials (Cunliffe 2013). Around this time, and in this region we see the appearance of an iconic artefact associated with huge change across much of Europe: the Beaker pot. These people began prospecting, mining and extracting copper ore in south-eastern Iberia, southern France and Amorica (part of modern Brittany). Taking their Beaker pots and new metal technology with them, these early metal workers soon came into contact with southern Ireland around 2400 BC (Cunliffe 2013; O’Brien & Brindley 2004). It comes as no surprise that at the earliest mining site at Ross Island in County Kerry, archaeologists found beaker pottery. Cunliffe (2013, p.201) makes it quite clear that “the absence of any earlier trace of copper-working in Ireland and the presence of Beaker pottery at the mining camp strongly suggests that the new technology was introduced by experts from abroad”. At Ross Island, miners generally focussed on surface deposits of tennantite-rich (Cu6[Cu4(Fe,Zn)2]As4S13) fahlerz and chalcopyrite (CuFeS₂) - arsenopyrite (FeAsS), though also dug galleries to depths of 13-18m (Cunliffe 2013; O’Brien & Brindley 2004). The main product output after the arsenic-rich copper had been smelted, was flat axe heads [LINK TO PRODUCT]. Later daggers and halberds would also be made of the copper which is called “group A”, and gives a distinctive marker to archaeo-metallurgists which allow them to trace the metal source (Cunliffe 2013). Mining continued for 600 years until flooding prevented further extraction, soon after mining had started at Mount Gabriel in County Cork from 1700-1500 BC (O’Brien 1996).

Some of the first metal objects in western and northern Britain were mainly made with Irish copper. Mining began in Britain a couple of centuries after Ross Island in Mid-Wales and at Pary’s Mountain, Anglesey between 2200 and 2000 BC (Timberlake & Marshall 2013; Williams & de Veslud 2019). Here, surface mining was followed by the digging of 20m shafts with the help of fire setting and stone hammers. It is quite possible the miners were initially attempting to recover native copper (a naturally occurring form of copper metal) rather than the sulphide ore which was extensively mined during the 18th century AD (Timberlake & Marshall 2013). Accounts from the 18thC suggest enormous lumps of native copper were found at Pary’s mountain, some as heavy as 15kg lying close to the surface (Timberlake & Marshall 2013). Much of the prehistoric evidence of mining was destroyed by modern extraction, though on several occasions miners would come into contact with infilled shafts filled with charcoal and smashed pebbles. Estimates for the amount of copper extracted during the Bronze Age at Pary’s Mountain range between at least 2-4 tonnes (Timberlake & Marshall 2013).


Pebble Hammerstones at the base of a Bronze Age mining pit at Pary’s Mountain ©AncientCraft

Copa Hill near Aberystwyth (Wales) around 2100 BC, and continued to 1600 BC (Cunliffe 2013; Timberlake & Mighall 2003; Timberlake & Marshall 2013). Here miners exploited a seam known as the Comet Lode with open cast trenches which were washed and further exposed via drainage channels fed by several streams above the lode (Timberlake & Mighall 2003). Excavation found stone-lined channels and hewn out alder launders (open drainage pipes) which were used to carry/wash away debris and allow processing of the chalcopyrite ore. Like many prehistoric metal extracting mines, the Irish and Welsh copper mines yielded hundreds of pebble hammers for crushing ore using large stone anvils and mortars. These tools have been used as identifying features in landscapes which are suspected to have been mined during prehistory. At Copa Hill, as well as many hammer stones, wooden artefacts were found which paint a clearer picture of activities while the open cast was in use. As well as the alder and oak launders, baskets, withy hammer handles, rope and simple scaffolding was also found (Timberlake & Mighall 2003). Within the hills and valleys near Aberystwyth are many other Bronze Age copper mining sites which saw activity around the same time as Copa Hil.


A scree slope at Copa Hill left behind by Bronze Age miners. ©AncientCraft

A more well known mining site is to the north, on the limestone headland next to the town of Llandudno on the Great Orme. Operations appear to have begun around 1850 BC, and like Copa Hill, began with open cast mining (Cunliffe 2013). The copper ore at the Orme is malachite rather than chalcopyrite as a simple overview, however in truth the ore at the Orme is a malachite-goethite (copper-iron sulphide) (Williams 2017). Though malachites and azurites occur on the headland, they tend to be away from the main, more profitable veins and diluted with gangue minerals (Williams 2017). The workings descended downwards into the limestone and began to follow the veins more closely, wrestling in extremely narrow galleries which may have only been worked by children. The mine also boasts the largest humanly-made underground space as well as being the largest prehistoric copper mine currently known in Europe (Timberlake & Marshall 2013). Like the other Welsh mines, stone hammers and mortars were extensively used for breaking ore both underground and on the surface for processing. Simple bone tools were also used to chip and lever rock which were stained green over thousands of years of being in contact with the copper-rich soil. Recent sampling has recovered a number of small pieces of bronze believed to be the tips of bronze pickaxes. Complete examples exist from the Late Bronze Age - Iron Age salt mines at Hallstatt, Austria (Williams & de Veslud 2019). The mines at (and in) the Orme continued to see activity for nearly 1000 years, ending around 900 BC. The peak of activity at the mines was during the Middle Bronze Age at the “Acton Park Phase” around 1500-1400 BC (Williams 2017). During this time axe heads known as “palstaves” [LINK TO PRODUCT] were being produced and circulated around Europe. Research led by Williams (2019) found that over 95% of group I shield patterns palstave axe heads were made using copper from the Great Orme. It is likely that other objects from the Acton Park phase have a similar high proportion of copper from the mine. Amazingly these axes are not just found in Britain, but also in France, Belgium, Netherlands, Germany, Denmark and even Sweden (Williams & de Veslud 2019). This evidence demonstrates the copper mine at the Great Orme is connected to an exchange network over a wide geographic area that undoubtedly was linked to trading via sea and river routes. Estimates for the amount of copper metal extracted range between 232 and 830 tonnes (as extreme pessimistic and optimistic estimations based geological surveys), most of the copper came from two areas in the mine (Williams & de Veslud 2019). Activity continued on the headline during the Bronze Age right up to 900 BC when a small smelting activity space on the edge of the Orme was briefly used. However the ore veins in the later Bronze Age became harder to follow with a far poorer metal yield (Williams & de Veslud 2019).


There are several mines in England, Scotland and the Isle of Man, the most well-known of which is located at Alderley Edge in Cheshire. Here in sandstone outcrops from the Triassic, are veins of malachite, azurite, galena and cobalt (Gale 1990; Timberlake 2007). The metal oxides coat the sand grains in varying concentrations making it difficult to smelt due to the large amount of waste produced in the process (in the form of burned and fused sand grains). Though much of the Alderley Edge ridgeline saw mining activity in the last few centuries, the Bronze Age mining is concentrated at Engine Vein (Gale 1990). During the 19th and 20th centuries, small pits were truncated during the attempt to exploit the metal ore veins. These pits were cut downwards with smooth walls and bases and filled with hammerstones unlike others from prehistoric mines. These hammerstones have grooves pecked into them to facilitate better hafting with a hazel withy (Gale 1990). The process of digging was likely conducted by smashing the pebbles against the soft sandstone which would have “bruised” the rock and quickly reduced it to broken up sand. The late 19th C an oak shovel was discovered with a number of hammerstones which was later dated to around 1780 BC which puts it near the middle of the main activity period of 1900 - 1700 BC (Garner 1994). Recent survey and excavation found further pits and possible smelting areas around Engine Vein dating to around 2000 BC (Timberlake & Prag 2005). It is likely that Bronze Age mining activity extends further away from Engine Vein, based on the number of hammerstones found a reasonable distance away. However it is likely much has been destroyed by modern mining (Gale 1990). The relatively short period of activity at the Edge may be down to the difficulty in extracting copper efficiently for the amount of time and resources invested. Modern extraction methods relied on acid leaching in large pools which allowed prospectors to approve ores with a far lower yield.

River of copper oxide at West Mine. ©AncientCraft

Deep inside West Mine is a river of copper oxide which has leached out of the rock via groundwater and redeposited in a pool. James wonders how many axes could be made from such a deposit.


References


Cunliffe, B., 2013. Britain begins. Oxford University Press.


Gale, D., 1990. Prehistoric stone mining tools from Alderley Edge. Early Mining in the British Isles, pp.47-48.


Garner, A., 1994. The alderley edge shovel. An epic in three acts. Current archaeology, 12(137), pp.172-173.


O'Brien, W., 1996. Bronze Age Copper Mining. Princes Risborough: Shire Publications.


O'Brien, W. and Brindley, A.L., 2004. Ross Island: mining, metal and society in early Ireland. Department of Archaeology, National University of Ireland, Galway.


Smith, A.D., Green, D.I., Charnock, J.M., Pantos, E., Timberlake, S. and Prag, A.J.N.W., 2011. Natural preservation mechanisms at play in a Bronze Age wooden shovel found in the copper mines of Alderley Edge. Journal of archaeological science, 38(11), pp.3029-3037.


Timberlake, S. and Mighall, T., 2003. Excavations on Copa Hill, Cwmystwyth (1986-1999): an Early Bronze Age copper mine within the uplands of central Wales (Vol. 348). British Archaeological Reports Limited.


Timberlake, S. and Prag, A.J.N.W., 2005. The archaeology of Alderley Edge: survey, excavation and experiment in an ancient mining landscape. British Archaeological Reports.


Timberlake, S., 2007. The use of experimental archaeology/archaeometallurgy for the understanding and reconstruction of Early Bronze Age mining and smelting technologies. Metals and mines: Studies in archaeometallurgy, pp.27-36.


Timberlake, S. and Marshall, P., 2013. The beginnings of metal production in Britain: a new light on the exploitation of ores and the dates of Bronze Age mines. Journal of the Historical Metallurgy Society, 47, pp.75-92.


Williams, R.A., 2017. The Great Orme Bronze Age copper mine: linking ores to metals by developing a geochemically and isotopically defined mine-based metal group methodology. Archaeometallurgy in Europe IV. Bibliotheca Praehistorica Hispana, 33, pp.29-47.


Williams, R.A. and de Veslud, C.L.C., 2019. Boom and bust in Bronze Age Britain: major copper production from the Great Orme mine and European trade, c. 1600–1400 BC. antiquity, 93(371), pp.1178-1196.


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