"A Purdue University archaeologist discovered an intact ancient iron ore mine in South America that shows how civilizations before the Inca Empire were mining this valuable ore."

"The researchers determined that the mine is a human-made cave that was first created around 2,000 years ago. An estimated 3,710 metric tons was extracted from the mine during more than 1,400 years of use. The mine, which is nearly 700 cubic meters, is in a cliffside facing a modern ochre mine."

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