Research confirms Wyoming is home to the Americas’ oldest mine

Wyoming’s state archaeologist and University of Wyoming researchers have confirmed that an ancient mine in eastern Wyoming was used by humans to produce red ocher starting nearly 13,000 years ago.

The digs and research conducted on the Powars II site at Sunrise in Platte County have confirmed it to be the oldest documented red ocher mine — and likely the oldest known mine of any sort — in all of North and South America. The university reports that the excavations, completed shortly before the 2020 death of famed UW archaeologist George Frison, confirmed theories he advanced stemming from research he began at the site in 1986.

These findings appear in the Proceedings of the National Academy of Sciences (PNAS), one of the world’s most prestigious multidisciplinary scientific journals covering the biological, physical and social sciences. 

Wyoming State Archaeologist Spencer Pelton, who became involved in the Powars II project in 2016 when he was a UW doctoral student, was the lead author of the paper, “In situ evidence for Paleoindian hematite quarrying at the Powars II site (48PL330), Wyoming,”, published on May 12.

According to the university, Frison — who died in September 2020 as the only UW faculty member ever elected to the prestigious National Academy of Sciences — is listed as a co-author of the new paper. Other contributors were George Zeimens, executive director of the Sunrise Historic and Prehistoric Preservation Society; Erin Kelley, a UW graduate and Office of the Wyoming State Archaeologist staff member; and UW Ph.D. students Sarah Allaun, Alexander Craib, Chase Mahan and Charles Koenig.

Red ocher, also known as hematite, fulfilled a wide range of functions in Paleoindian societies, including as a pigment in rituals. It has been found at ancient graves, caches, campsites and kill sites in the Great Plains, the Rocky Mountains and beyond. The Powars II site is the only red ocher quarry identified in the North American archaeological record north of southern Mexico — and one of only five such quarries identified in all of the Americas, according to UW.

Among the artifacts previously discovered at the Powars II site are Clovis points — believed to be from the first inhabitants of North America — along with other projectile points, tools and shell beads.