Grant Garrett, a principal in Garrett Satellite Driven Excavation, a third-generation earthmoving company based in Hot Springs, Ark., equipped his first machine with a grade-control system six years ago. He quickly realized the competitive advantage the system provided, and today is a dedicated user of both 2-D and 3-D technology, which is employed from initial job layout to the finished grade. Grade-control technology, he says, has allowed the company to triple production on many jobs, compared with conventional grading techniques.
Perhaps one reason Garrett has been so successful with electronic grade control is his ability to combine high technology with old-fashioned human innovation. For example, on a recent job, the Garrett crew needed to move 170,000 cubic yards of dirt in 30 days to establish a 200,000-square-foot building pad.
The grading crew actually accomplished the task three days early by rough grading with a three-dozer combination. Two Caterpillar dozers, a D11 and a D9, each fitted with a Topcon 3D-GPS+ system, worked side-by-side to establish the angle and depth of rough-cut passes. On the left flank of the D9, however, was what you might call a "Copy Cat," a second Cat D11 that was manually controlled by a good operator who observed and closely duplicated the blade position of the two satellite-controlled machines on his right. The result was a moving wall of dirt 57 feet across and some 9 feet high.