Crews digging near an intersection in Duluth in preparation for future road construction have come across 55 coffins — all of them believed to be empty — as well as a single bone that appeared to be human.

St. Louis County Public Works employees were looking for any evidence of human remains as part of a planned archaeological exploratory dig last week in advance of a scheduled project to widen Rice Lake Road north of Arrowhead Road in 2020.

The coffins had no lids, said Steve Krasaway, resident engineer with the county. The bodies they once housed were likely removed during a 1960s grave relocation project, he said, though the coffins were left in the ground and are now filled with dirt. Workers discovered a lone bone outside the coffins.

The spot is located in a road right of way near a wooded area that once served as Greenwood Cemetery, where about 5,000 people who died at the former St. Louis County Poor Farm were buried from 1891 to about 1947. The cemetery was declared inactive in 2012.

Officials estimate that 100 to 125 bodies were moved from the cemetery in the 1960s, Krasaway said. But the cemetery's boundaries are still unclear, with no records providing guidance, he said.

It is not known to be an American Indian burial site, Krasaway said, but there may be some Indian remains included in the 5,000 who were buried there.

"There's still 4,900 bodies within this general area," Krasaway said. "We want to make sure we treat all of these remains with care and respect."

A team of archaeologists is being called in to look for any more bones. The Minnesota Indian Affairs Council, collaborating with the state archaeologist, will coordinate and pay for the additional study.

Pam Louwagie