Coast Guard Petty Officer Ryan Tippets said on Thursday barges are being allowed to proceed south with northbound traffic expected to move later.
He said 29 barge tows were waiting to head south, and 34 were in line to go north.
The river was reopened near Greenville Wednesday after a grounded barge was refloated. The waterway has been closed several times in August because of sand and mud blockages.
Dredging crews are active along the river in several states trying to keep a navigable channel open.
Weather forecasters say the Mississippi could remain low until October.