Malachite fragments, a mineral rich in copper, recovered during the excavation works at Cova 338. Credit: Maria D. Guillén / IPHES-CERCA.

In the past, scientists thought that prehistoric peoples only traveled briefly through high-altitude mountain areas, rather than staying to take advantage of their resources. But new evidence suggests that, starting about 5,500 years ago, a prehistoric community repeatedly climbed up to Cave 338, 2,235 meters above sea level in the Pyrenees, to collect and process malachite for copper—returning many times over thousands of years. Additional finds, including jewelry, suggest that much more remains to be found when excavations reopen this summer.

High in the eastern Pyrenees, archaeologists are revealing the secrets of a prehistoric cave full of hearths containing fragments of green rock that could represent early copper mining.…