Rogan cites estimate of 1.5bn pounds from ancient Lake Superior copper mines

In a discussion about early metallurgy, Joe Rogan reads out a figure shown on-screen describing an estimate of up to 1.5 billion pounds (about 680,000 metric tons) of copper extracted in the Lake Superior region over millennia. Button argues the scale suggests a sustained prehistoric copper-working “industry”, though the on-screen text notes the estimate covers long periods rather than a single era.