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| Aqua Master cutting trees under water. |
A look at some real environmental heavyweights
Some of the most challenging environmental projects involve fleets of diverse vessels and equipment with astonishing capabilities to move vast amounts of tailings, sludges, and high debris wastes for treatment. An Eastern Canadian company, Consolidated Giroux Environment Inc., a dredging and operating company, have added a new 370 Ellicott Dredge to their already sizeable fleet. This machine is completely equipped with 425 HP Caterpillar diesel, a special stern winch attachment and uses 12" pipe-line. Having a capacity of up to 6,000/USGPM, it is capable of moving tailings at rates of 150 to 300 y3/hr.
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| Aqua Master cutting trees under water. |
Its first job called for the relocation of 725,000/y3 of coal tailings from a Nova Scotia coal preparation plant. The project's requirement was to eliminate or substantially reduce acidification of water caused by air exposed tailings by relocating all the water tailings to the deep end of the lake, a distance of 4,000 feet. The project was completed on time in four months.
The new 370 Ellicott Dredge has completed jobs in Northern Ontario, Quebec, New Brunswick and Newfoundland.
Consolidated Giroux Environment operate a fleet of eight Ellicott Mud Cats (MC915-MC915X) for lime and lime hydroxide relocation, primary and secondary paper sludge, chemical sludge, metal recovery, maintenance dredging and encapsulation of hazardous waste. They also operate a variety of water crafts that can cut trees under water and transport them along with other debris to shore for disposal. In addition, they operate dredges which are capable of handling high debris material with non-clogging pumps.
In Canada, they have been involved in some of the largest environmental dredging projects of this type. One such project involved relocating 1,000,000 y3 of lime and lime hydroxide waste, complicated by free-standing trees and brush in a pond, and pumping 10,000 feet using booster stations.
Dredging began at a critical point where the settling pond discharges into a river, which feeds into Hudson Bay, an extremely environmentally sensitive area. The lime material being dredged was laced with heavy metals. For these reasons, the dredge had to have the following characteristics:
The previous year, a local contractor was hired to conduct a test patch with a standard Mud Cat dredge, but the test was unsuccessful.
Consolidated Giroux used a Mud Cat 915 that was modified with a new pump capable of handling high debris waste. A 10" x 12" pump capable of 6,000/USGPM was chosen, which required a new 375 HP engine and other adaptations. They also modified the auger and boom system in order to handle the specific type of material and higher volumes. All modifications were completed at their facility in Charlo, New Brunswick.
The trees and underbrush required specific equipment for removal. A barge was fitted with a backhoe loader, a sheer, stabilizers and spuds, allowing it to sheer the trees at eight to nine feet below the water level (capability to 20'). The barge had a hydraulic propulsion system to allow it to position itself or move around the pond as required. The shop maintenance staff named this machine "Aqua Master".
Working with the Aqua Master was a self-propelled transport barge with a moving conveyor platform. Trees and debris were loaded onto this barge, transported and discharged on land by means of the barge moving conveyor in seconds. All this equipment was truckable.
The booster stations consisted of three 238 HP with 10" pumps which boosted the material the final 7,000 feet for a total pumping distance of 10,000 feet to a holding area. A total of 23,000 feet of high-density polyethylene pipe in 8-, 10-, and 12-inch diameters was used on this job.
Eleven 48-foot trailer loads of equipment were required to set up the job and highway tractors traveled a total of 25,000 miles to mobilize the project.
The initial contract to remove 500,000 y3 of material was begun in June 1992. This project was so successful that the smelter owner contracted an additional 500,000 y3. The entire job was completed by mid October.