DULUTH (AP) -- The freighter that ran aground in the Duluth harbor is back in operation.

Duluth Seaway Port Authority spokeswoman Adele Yorde says the U.S. Coast Guard cleared the ship, American Spirit, to set sail Monday morning because there was no structural damage. Yorde says it later left the harbor loaded with iron ore pellets.

The Coast Guard will continue to investigate why the freighter ran into trouble Sunday afternoon, coming to rest just offshore from a break wall in Canal Park. No one was injured when the ship ran aground.