Personnel from Coast Guard Sector Upper Mississippi River have contacted and safety-checked more than 74 towing vessels and examined 310 mariner licenses and have found no discrepancies in the early phases of Operation Big Tow in the upper Mississippi River region. Operation Big Tow, a national initiative that began in the upper Mississippi River region Saturday, is using safety spot checks, vessel and operator credential examinations, and company audits to ensure towing vessels are being operated safely and are manned by properly licensed individuals. To minimize the impact to vessel movements or the flow of commerce, the Coast Guard is working with industry and towing vessel operators to conduct examinations at locks and dams…