Advanced Copper Fabrication Methods


"Cahokia coppersmiths used a process of lamination 600 years ago."

MetalMiner, Taras Berezowsky

Cu mining methods

Today, we'll turn toward metal sourcing and fabrication of a rather ancient sort—the methods used to smith copper by the Cahokia, a Native American people who lived 600 years ago on the banks of the Mississippi.

Living and working way downstate from our contemporary steelmaking hub of Chicago-Hammond-Gary, the Cahokia were famous for building towering mounds in Southeastern Illinois—the purpose of which scientists are still not 100% clear on. However, their usage of copper has also gotten some attention.

Northwestern University researchers have undertaken metallurgical analyses of the copper finds there, and have discovered that the microscopic structure of the copper metal holds clues to how it was, well, fabricated:

Science Explains Ancient Artifacts from Northwestern News on Vimeo.

Especially interesting is the conclusion that Cahokians used a process of lamination, essentially hammering two pieces of copper together.

Although some of the methods employed by the researchers may elicit a "why?" response, Deymier-Black and Chastain recreated the metal-working process in the lab with natural copper nuggets, fire and a heavy stone, pounding and heating the copper into thin sheets (really?)—the science behind the history that led industrial firms do what they do so efficiently with primary copper production today is nonetheless fascinating.

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