Except for the transition from a hunter-gatherer to a farming economy, the introduction of metallurgy is perhaps the most transformative development experienced by prehistoric societies, both in economical and societal terms. Among the various factors underpinning this process, changes in mining technology on the one hand and in the social organization of mining activities on the other both play a crucial role.
Ideally, technological and societal aspects of early mining should thus be studied in conjunction, to allow for a fuller understanding of how and why different communities adopted metallurgy at different times, under different circumstances and not always with the same consequences.
In most instances, however, evidence for the study of both the technological and the societal side of early mining is not readily available in equal measure. Rather, availability of adequate data on prehistoric ore extraction and processing sites, settlements and corresponding burial grounds from the same micro-region is the exception rather than the rule.
This also applies to the Iberian Peninsula, despite of its abundant and varied mineral deposits, some of which were exploited at least since the 4th millennium BC. While its most prominent Chalcolithic (Los Millares) and Earlier Bronze Age (El Argar) cultures are centred in the Southeast, where copper minerals are also present locally, efforts to identify archaeological evidence for prehistoric mining have mostly focused on the particularly mineral-rich northern and western parts of Iberia.
Attention in the Southeast so far has concentrated almost exclusively on the remains of Punic and Roman mining activity around Cartagena. It comes as no surprise then that there is currently no evidence for ore extraction from south-eastern Iberia predating the later 1st millennium BC.
The lack of any earlier evidence has generated some debate on the potential reliance of 3rd and 2nd millennium communities in the Southeast on imported metal and the socio-economical implications of such a dependence. The question needs to be asked, however, whether the absence of any earlier evidence here is indeed to be taken as evidence of absence, given that very little systematic survey work has been conducted so far to locate traces of prehistoric mining activity in the region.
Reasons for this state of affairs are varied. Generally, any attempt at identifying relevant evidence requires initial recording of all mining-related remains in a given survey area, regardless of date. Even based on a full body of survey data, at sites with a complex history it can still prove rather difficult to identify traces of prehistoric mining activity among later remains. Good knowledge of local ore bodies is also essential for an effective survey. Remote-sensing techniques tend to be of limited use in attempts to identify prehistoric mining remains, and the terrain often does not lend itself easily to standard walk-over techniques.
In light of those issues it was felt that in order to develop a coherent strategy for addressing the questions at hand, a pilot survey should be conducted in a limited area with both a known history of copper mining and evidence for prehistoric settlement.
Based on these criteria, we chose the sierras bordering the Lower Segura valley for our initial survey area, focusing particularly on the Sierra de Orihuela and Sierra de Callosa, situated on the border between the modern-day provinces of Alicante and Murcia.
Previous research here had identified both a significant number of settlement and burial sites dating to the 3rd to 1st millennia BC as well as the presence of copper ores easily accessible to prehistoric miners. Historical records attest to the exploitation of copper, iron and gold in the area during the post-medieval period, and the slopes of the Sierra de Orihuela are dotted with abandoned mine shafts and spoil tips.
The primary objective of our two pilot survey campaigns in 2010 and 2011 has been to compile a database of all surviving mining remains in the Sierra de Orihuela and Sierra de Callosa, regardless of their date, and to systematically collect copper ore samples from relevant sites for minor-element and lead-isotope analysis.
So far, more than a hundred extraction-related sites have been catalogued, from small exploratory open-cast pits to complex systems of shafts and galleries, and a substantial number or ore samples have been collected. Most of the surveyed sites date to the 19th and 20th centuries AD, but an iron mine of Later Iron Age or Roman date and a prehistoric basalt extraction pit have also been identified.
Direct evidence for prehistoric copper mining is still lacking, but given the scale of later mining activities in the area it would not come as a complete surprise if any traces of Chalcolithic or Early Bronze Age ore extraction had since been obliterated.
The lack of direct evidence for prehistoric copper ore extraction notwithstanding, some of the data gathered over the course of our project would seem to indicate that copper was indeed mined in the area during prehistory. Our 2011 survey campaign has yielded clear indication of ore processing at an Early Bronze Age settlement on the aptly named Cabezo de la Mina. While one cannot rule out the possibility that the copper ore processed at this site might have come from further afield, long-distance import of copper mineral to a settlement sitting right on top of a major and easily accessible ore body seems unlikely.
Apart from mining-related sites, our survey has also identified a number of other archaeological remains that had not previously been recorded. In chronological terms these range from later prehistory to the post-medieval period and include a range of different types of site, complementing our existing knowledge of settlement patterns in the study area.
Concerning future work, while the 2010 and 2011 campaigns have already yielded a large body of information, some parts of the study area are still in need of more intensive survey. In order to enhance the chronological resolution of our GIS-based analysis of settlement patterns, we are also planning to open test trenches at selected sites to acquire relevant stratigraphical data.
Additional data are also required to address the issue of raw material provenance for Chalcolithic and Bronze Age metalwork from the study area. Forthcoming analytical results from our ore sampling programme will for the first time allow for comparison between local copper minerals and finished objects in terms of minor-element composition. The existing body of minor-element data from metalwork with a secure local provenance is rather limited, however, and no lead-isotope data are currently available. Hence, apart from further fieldwork in 2012 we are going to embark on a programme of sampling metalwork objects from earlier excavations, in order to fill this lacuna.
Besides these strictly scientific objectives, our project is also taking an active role in efforts by Orihuela council to foster green tourism in the area, informing their strategy to raise awareness of the Sierra de Orihuela’s mining heritage and developing a concept to integrate some of the more prominent sites recorded by our survey in sign-posted walks, while restricting public access to unsafe mines.
The project team includes researchers from Queen's University Belfast, Ruhr-Universität Bochum, the Freiburger Institut für Paläowissenschaftliche Studien, Museo de Arqueología de Orihuela and Universidad de Murcia.
We would also like to acknowledge crucial IT support from ArchGate project staff, who never lost their nerve in trying to respond – mostly on very short notice – to what must have appeared to them some quite bizarre requests to tailor the ArchGate software to our outlandish project needs.
Funding for the project was kindly made available by the British Academy from its Albert Reckitt Archaeology Fund.
Please click here for a preliminary note on the 2010 campaign, published in the Prehistoric Society's newsletter PAST (# 67, April 2011).
Information released to the local press release following our 2011 campaign, including some footage from the respective press conference is available at the following URLs: