At over 2,200 metres altitude in the Catalan Pyrenees, an inconspicuous cave hides one of the oldest copper processing workshops ever discovered in Western Europe. Cova 338, excavated by researchers from the Autonomous University of Barcelona and IPHES-CERCA, has yielded evidence of intensive malachite processing spanning 4,000 years, from the 5th millennium BCE to the late 1st millennium BCE. Published in Frontiers in Environmental Archaeology, the study reveals that the high Pyrenean mountains were not a marginal zone, but a strategic pillar of the regional prehistoric economy.1

A Workshop Cave at 2,200 Metres

Cova 338 is a small limestone cavity perched in the Catalan Pyrenees, today accessible only to hikers and mountain wildlife. Excavations revealed nearly 200 fragments of green stone (malachite) associated with charcoal in 23 combustion hearths spread throughout the site's stratigraphyStratigraphyThe study of the superimposed layers (strata) of an archaeological site; each layer corresponds to a phase of occupation and yields a relative chronology.. Malachite, a green copper carbonate, does not occur naturally in the cave: it was therefore transported from external deposits, processed on-site by heating, and converted into metallic copper by pyrochemical reduction.

Ötzi the Iceman, contemporary with the Pyrenean metallurgists
Ötzi the Iceman, who died in the Alps around 5,300 years ago, carried a copper axe similar to those produced at Cova 338. His Pyrenean contemporaries were extracting and transforming this metal in high-mountain caves. (Credit: Thilo Parg, CC BY-SA 2.0, Wikimedia Commons)

Radiocarbon dating of the charcoal traced almost continuous occupation between 4,900 and 900 BCE, representing 4,000 years of metallurgical activity at a single site. This exceptional longevity suggests Cova 338 was not a transit camp or emergency shelter, but a specialised production site, regularly visited by communities that had detailed knowledge of the mineralogical resources of their high-mountain environment.

The Green Gold of the Pyrenees

Malachite, nicknamed "green gold" by the researchers, was a rare and precious resource in ChalcolithicChalcolithicThe "Copper Age": a transition between the Neolithic and the Bronze Age, marked by the first copper objects (Ötzi's era). and Bronze AgeBronze AgeA protohistoric period following the Neolithic, defined by bronze metallurgy (a copper-tin alloy) and the rise of the first cities and states; in Egypt it corresponds to the age of the first pyramids. Europe. Converting it to metallic copper required sophisticated technical mastery: malachite must be heated above 1,000°C in a reducing atmosphere, an operation requiring bellows, abundant fuel (pine wood was available at these altitudes) and specialised know-how passed down through generations.2

Chalcolithic lithic tools, transition period towards metallurgy
Lithic tools from the Chalcolithic (or EneolithicEneolithicThe "Stone-and-Copper Age": a transition between the Neolithic and the Bronze Age (c. 5000–3000 BC in south-eastern Europe), marked by the first copper objects, large farming settlements and, in places, the rise of fortified sites. Broadly synonymous with Chalcolithic.) period, the transition phase between the NeolithicNeolithicThe "New Stone Age": a period marked by farming, herding, settlement and pottery, from around 10,000 BC. and the Bronze Age, during which the first copper metallurgies emerged in Europe. (Credit: Fæ, CC BY-SA 3.0, Wikimedia Commons)

The copper produced at Cova 338 was probably intended for distribution through regional exchange networks. Copper objects of similar chemical compositions have been found at lowland sites in northern Iberia dating to the same period, suggesting that the Pyrenees constituted one of the metal supply sources for the Chalcolithic and Early Bronze Age cultures of the entire region.3

High Mountains: The Industrial Heart of PrehistoryPrehistoryThe span of human history before the invention of writing, from the Palaeolithic to the Metal Ages, known mainly through material remains.

The Cova 338 discovery fits within a broader archaeological trend: the revision of the role of high-mountain zones in the prehistoric economy. Long seen as marginal spaces, accessible only in summer and of little productivity, mountains are now recognised as strategic resource zones, intensively exploited by prehistoric populations for their game, minerals, pastures and timber. The high Pyrenean mountain was not the wild "wilderness" once imagined: it was a deeply anthropised space, integrated into the economic networks of southern Europe for at least 7,000 years.