Big Bend Dam was constructed by the Army Corps of Engineers and is located on the Missouri River in central South Dakota. It forms Lake Sharpe which extends for 80 miles upstream to Oahe Dam. While Big Bend Dam provides for flood control, irrigation, and recreation, one of its primary purposes is to impound water to power the hydroelectric plant’s eight turbines. Flow to each turbine is regulated by three intake gates. At peak capacity the power plant produces 493,000 kilowatts of electricity.
This project required Alltech to replace the wire ropes that operate the eight spillway tainter gates. Each tainter gate is operated by an electric hoist that drives two drums. Each drum has five wire ropes for a project total of 80 wire ropes to be replaced. A bulkhead was installed in the bulkhead slots upstream of the tainter gate and the area between the bulkhead and tainter gate was dewatered. Alltech was then required to split the drum discs apart to remove the existing wire ropes and to install the new wire ropes. New threaded shafts were provided for the drum discs, and the wire rope tension was equalized for each gate. The drum disc surfaces and shaft ends were also recoated as part of this project.