SHARECOMMENTMORE

The Army Corps of Engineers says crews are making "fantastic" progress clearing treacherous bedrock from a channel south of St. Louis near Thebes, Ill.

Barge operators are worried that water levels in that section of river may get so low that weight limits on shipments could be further tightened, effectively halting shipping.

Coast Guard Lt. Colin Fogarty said Friday that an eventual shutdown is possible but unlikely, given the corps' progress at Thebes and its water releases from at least two Midwest lakes into the Mississippi.