CHICAGO - The largest U.S. flour miller Ardent Mills has resumed bulk shipments at a mill in Alton, Illinois, as floodwaters along the Mississippi River receded while a mill in Chester, Illinois, “likely will be down for multiple weeks,” company spokeswoman Mary Ann Strombitski said on Tuesday. Near-record high floodwaters following deadly winter storms forced the company to shut down the mills a week ago. Ardent Mills is operated jointly by Cargill Inc, ConAgra Foods Inc and CHS Inc.