Thu July 06, 2006
Jeff Cronin
Transforming land into a Subtitle D landfill cell calls for a lot of precise earthwork.
Anyone who says otherwise is just talking trash.
Cooper, Barnette & Page Inc. of Statham, GA, is in the midst of a 90-day project to construct a 13-acre subtitle D landfill cell in suburban Atlanta.
They’re meeting the quick schedule with a crew numbering approximately 25 people and a fleet of 30 pieces of Caterpillar equipment.
But leading the charge are two D6 dozers equipped with the AccuGrade system.
“Sometimes I think that we could use a third one,” said General Manager Bruce Page. “It’s a huge investment, but it’s been paying off.”
Approximately 250,000 cu. yds. of rocky dirt is being excavated at the site, 45 percent of which is on a 4-1 or 3-1 slope.
Working on such steep grades are made easier with AccuGrade, Page said. It’s tough to keep a machine going on a hill all day, and it’s even tougher to work around grade stakes at that angle.
The AccuGrade system works in one of two ways — global positioning system (GPS)-controlled or laser-controlled.
In the GPS version, which is on the Cooper, Barnette & Page dozers, components mounted on the machines work with a system of 24 navigation satellites controlled by the U.S. Department of Defense and an off-board station somewhere on the job site.
Once programmed by a GPS technician, the system provides the operator all the information needed to perform the job to specs on a monitor in the cab.
The laser system includes machine mounted components and an off-board transmitter. It automatically controls the lift and tilt of a dozer blade. The transmitter emits a thin beam of light that rotates 360 degrees, creating a reference point from which the system determines the appropriate blade position. An in-cab display informs the operator of cut or fill requirements.
Page said his operators have easily adapted to the new technology. With traditional surveying, it takes an excellent operator to match the design.
“Here, you can take an operator with good skills and make a great operator out of him,” he said.
On a recent sunny morning at the site, the challenge of the rock-laden soil was apparent as an operator in a Cat dozer wrestled with a large boulder. After a series of attacks, the operator dislodged the rock, which was then scooped up by an excavator into one of 10 Cat artic trucks (both 740s and 730s) at the site.
For more extreme encounters with rock, Page said a Cat D8 dozer is equipped with a single shank ripper. While a challenge, it wasn’t unexpected, as soil tends to be rocky throughout northern Georgia.
Work at the site began May 17 and is to be complete within 90 days. By mid-June, Page said the crew was on target to finish “weeks ahead of schedule.”
In addition to excavation, the work includes placement of a clay liner; screening; construction of a leechate collection system with manholes, piping and a force main; and reclamation of a sediment pond.
Getting the grade just right is of utmost importance at this site, as state officials monitor each step to ensure it meets environmental regulations. The material has to be the right size, too.
“When the state comes out and checks things out, you can only have a certain particle size,” Page said.
The grading is especially important where this cell ties in to an existing landfill cell. The grade of the new cell has to match that of the other one, Page said.
Strict specifications are placed on each level of the landfill, from the soil base to the first layer of waste.
Once the subgrade is prepared, a layer of clay, screened on-site to 0.25-in. through one of three Extec machines, is placed on top in four 6-in. lifts. Page said each lift has specific requirements so, by the time that layer is completed, the material has been tested three or four times.
With a high demand for screening on this job, Page said the company decided to bring on an Extec E-7 screen, its latest model. The contractor already owns an S-5 and a Turbotrack.
The clay material has to be so fine because of what comes next — a 60-mill plastic liner that protects the ground from harmful materials. Subcontractor ESI of Louisiana is in charge of placing the 22-ft. wide panels atop the clay, fusing them together and air-testing to ensure they will do the job correctly.
While one half of the project is being lined, Page’s crew will wrap up work on the other half of the landfill to prepare it for the liner.
The liner is protected on top by 24-in. layer of screened sand material, which is known as the protective covering.
One of Yancey Bros.’ top five customers, Salesman Mike Potts said they’ve worked hard to keep Cooper, Barnette and Page’s machines up and running, knowing they’ve got a tight deadline. He said they were having start-up issues with one of the trucks, but the Yancey service department responded within a half-day and had it up and running in no time.
Founded in 1989 as an offshoot of Speedway Grading, Cooper, Barnette & Page has been constructing landfills for decades. It has also constructed schools, roadways, recreational complexes and industrial developments throughout Georgia and the Southeast. CEG