The U.S. Coast Guard continues to monitor a 629-foot cargo ship which ran aground Wednesday, Aug. 9 in the Upper Peninsula. The merchant vessel, Calumet, was empty at the time it ran aground in on the St. Marys River. Following an assessment, the Army Corp of Engineers say the vessel is structurally sound. As a precaution, boom will be placed on the water’s surface to protect the environment. A salvage plan is still being finalized. The cause of the grounding remains under investigation.