Field crews use track equipment and attachments to install 3,000 poles in southeast Kansas following an ice storm.
An inch of ice coated the copper weld conductor lines in southeastern Kansas in December 2007. The weight of the ice stretched the lines to the limit, snapping hundreds of poles like twigs. The storm knocked out power to 2,000 residents and affected more than a third of Twin Valley Electric Cooperative's service territory.
Following the storm, linemen spent five days getting the lines up and back in service. The cooperative also worked with the Federal Emergency Management Agency (FEMA) to determine what assistance would be available for repairing the storm damage. Months later in 2009, FEMA approved funding for the cooperative to reconductor the damaged lines and install heavier 40-ft, class 4 wood poles with shorter spans.
For this three-year project, which is expected to be completed at the end of this year, the linemen are replacing about 3,000 poles in an area with thick layers of limestone along a 150-mile stretch of line. To maneuver the muddy fields and bore holes into solid limestone, Twin Valley opted to invest in 299C track loaders from Caterpillar as well as auger, pole-setting and drilling attachments from Harleman Manufacturing.
Six years ago, Harleman brought a ground force auger to one of Twin Valley's job sites to demonstrate it for the field crews. In this particular location, the linemen faced challenges when it came to digging holes with a standard digger truck. They were spending up to four hours digging a hole through the rock. In addition, they were facing maintenance and repair issues due to the excessive vibration and pressure placed on the auger and booms.
Harleman's auger mounted on a skidsteer loader, however, dug the holes much faster than the digger truck and setup time was considerably faster. The cooperative purchased an auger unit and mounted it on its ASV compact track loader. The auger worked so well for the field crews that when the work started on the pole-replacement project following the ice storm, the company purchased two 299C Caterpillar track loaders as well as two more Harleman ground force augers.
To maximize efficiency, Twin Valley sends out an operator with the CAT 299C and auger ahead of the pole-setting and line-stringing crews to dig holes. That way, the cooperative isn't tying up some of the company's more expensive digger trucks and eliminating the time of an entire crew just to dig holes.
Typically, in the areas where the limestone is clear to the surface, it would take about three to four hours to dig a hole with a digger derrick. Using a Caterpillar compact track loader with an auger attachment, however, linemen can dig a hole in solid rock in less than an hour. The cost of the Cat and auger is less than half the price of a digger derrick truck, plus it only takes one person to operate it.
The auger features a hydraulic driving unit, which mounts on a compact track loader or any type of heavy duty skid steer equipment. When mounted on the Caterpillar equipment, the field crews place rear-outriggers on it so the linemen can put the full weight of the Caterpillar on the auger unit plus the 2,000 pounds of counter weight. On the other hand, when the field crews try to dig a hole with a standard digger truck, the only pressure they can put on the auger is the hydraulic pressure on the boom of the truck.
To use the auger, the linemen simply pull up to it, connect it to the compact track loader in a matter of minutes and then drive to each stake to dig a hole. The operator can position the auger easily and start digging. The operator has full visibility of the auger and the hole being dug from inside the cab, and he can operate it and dig the hole without getting off the unit.
Currently, the linemen are using 18-inch augers to dig the holes 6 feet deep. Harleman also offers a 24-inch auger, but for the size of the poles that the Twin Valley linemen are setting on this project, the 18-inch augers work well. The operator learns quickly how far to drill down without having to get out and measure the hole to make sure it is deep enough.
Working in Any Weather Condition
Twin Valley currently has two Caterpillar units running about 10 hours a day to dig the holes for the new poles on the project. By using the track loaders, crews are able to get work done even in adverse weather conditions. If linemen didn't have this equipment, however, they would likely be reluctant to drag their digger derrick trucks out into the muddy fields.
By using units on tracks rather than on wheels, the linemen also have increased maneuverability. Often, the operators needs to adjust the position of the Caterpillar unit to where they need to set the poles, and in a rubber tire unit, the tires would spin. As a result, it is difficult for the operators to maneuver out of ruts. With the track units, however, operators can easily move them 3 to 4 inches without having to completely reposition the unit.
Using the Caterpillar equipment, the soil conditions also don't slow down the field crews. The operators can drive the equipment, even if it's muddy, and they won't make ruts in the land. Using traditional equipment with tires, however, the operators would leave significant, long-lasting marks in the soil.
The Caterpillar compact track loaders only have two to three pounds of pressure per square inch as far as their impact on the ground. This is almost less than a human being. For that reason, the operators can drive across customers' yards and not leave any tracks.
Using Other Attachments
In addition to using the ground force auger, Twin Valley purchased several other attachments from Harleman. Like the auger, these attachments quickly attach to the Caterpillar units. For example, the pole-setting crews are now using a pole-setting attachment, which allows the operator to pick up a pole, carry it to the hole and set it without tying up a digger derrick truck. This attachment has come in handy when the field crews are working off the road. In addition, the linemen often use this attachment when the soil and terrain conditions make it difficult to access the hole with a digger truck, as is the case in wet conditions.
In these situations, the operators simply drop off the auger unit by unhooking the hydraulic hoses and flipping a lever. They then attach the pole-setting unit, pick up the pole and then drive out into the muddy fields to set the pole.
The company also purchased a tree saw that mounts on to the equipment to remove trees or other vegetation. They simply drop the auger, put the saw on, cut down the trees, and then re-install the auger and keep on going. They also have a blade, bucket and grapple hook attachment that allows the Caterpillar units to be used for a variety of different projects. Rather than just digging holes with the Caterpillar equipment, the field crews also use them for many other purposes.
By using the compact track loaders and Harleman attachments, the linemen are strengthening the distribution lines in southeast Kansas. That way, if another severe ice storm hits the region, the stronger poles, shorter pole spans and new poles will hopefully withstand the weight of the ice and keep the power on for residents in southeast Kansas.
Ron Holsteen (firstname.lastname@example.org) is a manager at Twin Valley Electric in Altamont, Kansas. He has more than 30 years of experience in the power industry. Previously, he worked for Nebraska Rural Electric Association, Seward County Rural Public Power and the South Dakota Rural Electric Association.
Caterpillar Inc. www.cat.com
Harleman Manufacturing www.harlemanmfg.com
Twin Valley Electric Cooperative www.twinvalleyelectric.coop