Paleolithic hunter-gatherers in South Africa would seek out specific areas to mine stone for their tools, according to a new study, challenging the idea that early humans collected their raw materials by accident.

The study, published on Tuesday in the journal Nature Communications, analyzed findings from the Jojosi excavation site in eastern South Africa, including numerous traces of hornfels, a metamorphic shale used in Stone Age tools. 

“On our very first visits, both on foot and using drones, we discovered about a dozen sites where perfectly-preserved, unweathered hornfels flakes were visible in eroded sediment, an absolute rarity for an open-air site,” Will said, adding that mainly “production waste” was found at the site.

According to the study, the absence of completed tools (end product) at the site, alongside the lack of other activity or settlement there, indicates that Jojosi was used only as a quarry.

“People worked cobbles on site here and knapped the material until they had achieved the desired shape from the rock,” Will said. “Probably to make tools from it later.”

Luminescence dating, which measures how long ago sediment grains were last exposed to sunlight or heat, showed that the site showed that it had been in use until approximately 110,000 BCE, the study explained.

Based on this, researchers suggest that early homo sapiens planned for the long-term acquisition of resources earlier than previously thought.

A total of 353 left-behind pieces found at the site were successfully reconstructed into their original forms by Gunther Möller, a PhD student at the University of Tübingen’s Institute of Prehistory, Early History and Medieval Archaeology.

“With these 3D puzzles, we were able to see precisely where and how material was chipped off and in what order,” Möller explained. “Several of these puzzles together then allow us to draw conclusions about the form of the actual end product, before it was taken to another place.”