Amphibious Vehicles Needed to Work Large Dredged Material Sites
RPB Equipment’s Hyundai machine mounted on an EIK AM300 undercarriage in a Matagorda Bay, Texas DMMA last summer. Using the EIK long reach crane and bucket, the contractor created 3,000-foot-long channels in the material to achieve net dewatering of five feet. Photos compliments of EIK.
Managing large dredged material placement sites requires a vehicle that is stable in wet and viscous material, and even in flooded areas. EIK Engineering’s low ground pressure tracked vehicles have been effective in two dredged material sites and two coal combustion residual (CCR), or fly ash, ponds in the U.S.
The basis of the vehicles are buoyant pontoons equipped with tracks that form an undercarriage on which an excavator of choice can be mounted. Optional side pontoons equipped with spuds can be installed for further stability in extremely muddy and viscous material, and allow the excavator to operate in up to 14 feet of water. The wide polymer track cleats can also paddle the machine, providing propulsion in flooded areas. These elements anticipate the most unstable conditions possible, which make them especially useful in an active site where the percentage of solids can vary widely. The multi-synchronous hydraulic drive avoids the limitations of a chain drive and provides the mobility and power needed to push and pull the machine through slurry and dry ground in sites that are recently filled or even in the process of being filled.
In Matagorda, Texas, the dredged material management areas (DMMAs) are designed to accept material dredged from the GIWW and the Matagorda Ship Channel, and to dewater back into the bay. In July and August 2017, RPB Equipment used a Hyundai machine equipped with an EIK long reach crane and excavator mounted on an EIK AM300 undercarriage to create 3,000-foot-long dewatering channels in one of these sites, and achieved net drainage 5 feet deep.
Maintenance material from the Houston Ship Channel is dewatered into large channels created within the Clinton Park DMMA. This site is north of the channel and bordered by I-610.
The Clinton Park DMMA is used for maintenance dredged material from the Houston Ship Channel. It is north of the channel, and just east of Interstate 610. The site is 1.3 miles long and 2,100 feet wide, and is dewatered by creating long, broad trenches that collect the water from the slurry.
Two amphibious excavators belonging to Houston Heavy Machinery of Cypress, Texas, were used in the Clinton Park site in a recent contract. They were a CAT329E equipped with an EIK 60-foot-long crane mounted on an EIK AM300 undercarriage, and a CAT324 with EIK crane, mounted on an EIK AM250 undercarriage.
Santee Cooper’s EIK excavator stacks material for dewatering in a fly ash pond in South Carolina. The material is being dewatered in place, and will then be moved to another location for beneficial use in a variety of products. This machine was converted from a standard excavator to an amphibious excavator by replacing the original tracks with the EIK undercarriage.
Santee Cooper, South Carolina’s state-owned electric and water utility, recycles the fly ash from its coal-powered generating plants, periodically dewatering and emptying the CCR ponds using amphibious excavators owned by the utility.
The ash is used to make concrete, mineral filler in paints and shingles, and for stuccos, mortars, and bowling balls. The settlement ponds are often under water, muddy and unstable with material that is 20 percent water. Conventional crawler excavators can work from the banks in the dry areas, but only amphibious excavators can access the entire pond.
For an ongoing project to work in the ponds, EIK technicians aided the equipment company Blanchard CAT of South Carolina in converting a standard CAT326F excavator to an amphibious excavator for use at Santee Cooper. They removed the original crawler and installed a new center frame that attached to the EIK AM250 undercarriage system. They then reconnected the hydraulic lines and installed a 60-foot long-reach crane with excavator bucket.
In 2014, the City of Independence, Missouri, voted to stop burning coal at two electrical plants for environmental reasons. The plants were operated by the city-owned Independence Power & Light. One plant was decommissioned, and the other converted to natural gas. Part of the closure process was to dewater three fly ash impoundments of 4.7, 14.9 and 17 acres.
Local contractor Radmacher Brothers Excavating Company, Inc. completed the year-long reclamation project this July. It dewatered and stabilized the area using a CAT329 excavator mounted on an EIK undercarriage. A trench and sump system consisting of combinations of open trenches and surcharges expedited moisture migration. After the material stabilized, Radmacher capped it with geosynthetic clay liner and a 12-inch topsoil cover, finishing the project on time and under budget.
Radmacher Brothers amphibious excavator works in a fly ash pond reclamation near Independence, Missouri. After dewatering and stabilizing the material, the company capped the pond with a geosynthetic clay liner and a 12-inch topsoil cover.