* Project: Replacement of lock at Chickamauga Dam.
* Contractor: Britton Bridge LLC of Knoxville.
* Authorizing agency: U.S. Army Corps of Engineers.
* The problem: The original lock, which opened in 1940, is suffering from "concrete growth" and requires aggressive maintenance to stay in operation.
* Projected cost: $755 million, down from an estimated $858 million last year after the Corps of Engineers revised its estimates in light of a projected eight-year completion. So far, $185 million has been spent.
* Size: The new lock will be 110 feet wide and 600 feet long, allowing multiple barges to lock through at one time compared with only a single average-size barge that can use the lock for each lockage today. The original lock was only 60 by 360 feet.
* History: Construction was initiated in summer 2007 with road and bridge relocation work for Access Road in Hixson. Lock design was completed in 2009, and the cofferdam construction and fabrication of the miter gates, culvert valves and culvert bulkheads were completed in 2012. Fabrication of the approach wall beams wrapped up in 2013.
* Future schedule: Adam Walker, project director for the Corps of Engineers, estimates that the project, with full funding, could be complete in eight years.
- Compiled by Business Editor Dave Flessner, who may be reached at dflessner@timesfree press.com or at 423-757-6340.