The US Army Corps of Engineers says workers began repairing footlong cracks today to an Ohio River lock, and the project remains on track to be finished in two weeks. With no backup lock, the project is preventing barges from plying the entire length of the Ohio from Pittsburgh to Cairo, Illinois Corps spokeswoman Carol Baternik says the McAlpine lock was drained by last night of tens of millions of gallons of water. The water was pumped into the river. Crews began by scrubbing the massive steel gates downstream. Inspectors then wound along scaffolding to reach cracks near the bottom of the nearly 70-foot-high gates. Workers started welding one-thousand-pound steel plates over bigger cracks today to reinforce the gates. More than 100 workers are involved in the project. The work is continuing around the clock, with two crews on duty 12 hours each. The project has not caused a logjam of barges along the busy waterway, because barge companies were notified in spring of the scheduled repairs. They should be complete on August 22nd.