Rampart Hydro Services performed underwater hydrodemolition on the stilling basin floor of the Canyon Ferry Dam. The Canyon Ferry Dam is located about 20 miles east of Helena, Montana on the Missouri River. Global Diving and Salvage of Seattle, Washington was chosen by the owner, Bureau of Reclamation, as the repair contractor. The specifications called for removal of approximately 20 cubic yards of concrete at removal depths of up to 6″. Since the basin could not be dewatered, Rampart designed and built a special underwater hydrodemolition cutting unit to perform the work. The spilling basin floor was located under 50 ft of water, so this special unit had to be placed and leveled by a diver. Vegetable-based biodegradable hydraulic fluid was used for the control functions of the unit so that the water would not be polluted in case of hydraulic line damage or accidental leak. Fortunately, no leaks occurred. Rampart regularly uses vegetable-based biodegradable oil whenever there is a chance of regular hydraulic oil entering a body of water should a spill or line break occur.
Click here to view the underwater video.
Frank Immel, Marketing Manager for Global Diving and Salvage, recently published an article on the Canyon Ferry Dam project in the ICRI’s Concrete Repair Bulletin. The article appeared in the May/June hydrodemolition issue. Click here is read the full article.