Improper operation of an excavator while trenching, sloping or benching can have a big impact on productivity and can potentially place both people and equipment at risk. Oftentimes, it’s the result of poor or inadequate training. In other cases, it stems from bad habits, misconceptions about how a particular process should be completed or lack of planning.
“The most common mistake that I see made by operators is a failure to plan the approach to the excavation,” says Matthew Hendry, product consultant, hydraulic excavators, John Deere Construction & Forestry. “Beginning work without a complete plan, they unwittingly create ‘bottlenecks’ — for example, intersecting trenches or an access ramp in the way. Bottlenecks often require moving material several more times than necessary, significantly increasing job costs.
“Properly planning the dig will help to minimize those chances,” he continues. “Plan where you will put the spoil pile... where you will stage your pipe and bedding material. Plan where you will cross existing utilities and if you may need additional shoring around those locations.”
“Visualize what [the project] is going to look like when it’s finished and how it’s going to progress before you do,” advises Chris Cannon, a training manager with VISTA Training. “A lot of times, operators can get boxed in. They may put the spoil in a certain [area] and realize later that it’s a tight site and they can’t get out. They will have to climb over the pile, or they’ve created an obstruction for themselves.”
“Prior planning will prevent poor performance, minimize the chances of accidents and maximize your chance for productivity,” Hendry asserts.
Start with the right tools
As with most construction equipment applications, productivity and efficiency depend on selecting the right tools for the job.
“The first mistake — even before operating the machine — would be to work with a tool/attachment that is sized incorrectly based on machine reach, configuration and the material to be moved,” says Jeff Powell, general product manager - earthmoving equipment, Liebherr Construction Equipment Co. “The incorrect attachment may be too heavy and would influence the machine’s stability and performance.”
Selection of an excavator and attachment should be based on the production needs of the project. For example, Hendry notes, “Trenching 18 ft. deep and pulling two trench boxes will dictate a 35- to 45-ton machine configured with the right length arm to reach your depth, but also with the lifting capacity to handle lifting the boxes.”
Powell agrees, noting, “An application that requires a maximum reach of 40 ft. should not be done with a machine that can only reach 30 ft. Otherwise, you are trying to compensate for the missing 10 ft. with some ‘dangerous’ ideas — stick extensions, working on uneven slopes and even in loose materials, etc.
“Ensure that the right attachment for the machine is chosen, adapted to the material density, reach and machine configuration,” he emphasizes. “The machine itself has to be adapted to these long-reach applications [with] additional counterweight, wider undercarriage.”
Using excavators specifically designed for longer reach applications does require some additional precautions, however. “Super Long Front excavators (SLF) require very detailed project planning,” Hendry states. “They are very different machines as far as operating characteristics go.
“The long boom and arm configuration changes the balance and center of gravity significantly,” he explains. “Just walking an SLF through the project requires planning. Unlike a regular excavator that can use the boom and arm to lift and maneuver the excavator, the SLF can’t use the boom and arm in this manner.”