HANNIBAL, Mo. — The U.S. Coast Guard closed a portion of the Upper Mississippi River due to dredging operations, Friday. The Upper Mississippi River is closed to all vessel traffic from mile marker 306.4 to mile marker 306.6, near Hannibal. The U.S. Army Corps of Engineers has begun emergency dredging after a vessel ran aground in the vicinity, Friday. The Coast Guard urges mariners to monitor VHF-FM...