Battling The Elements Year-Round

May 2009 Vol. 64 No. 5

Whether it’s summer or winter, Minnesota’s landscape can pose problems for construction crews. “In Minnesota, being the ‘land of 10,000 lakes’ is not misstated. We had a lot of bog conditions,” says Walters, who served as project superintendent on the job. “Actually, the severe cold helped us in the winter because a lot of those wetlands in the spring would have been almost impossible to work in.”

But the winter also posed its own special challenges. The advantage of the ground being frozen is that it allowed Jinkerson and Walters to more easily position and maneuver their equipment on the jobsite. The disadvantage was difficulty in finding equipment that could cut through it.

“The frost in that part of Minnesota and in that time of year was as much as eight-feet deep,” Walters says. “Let’s say you have to have a six-inch bed, a 24-inch pipe and four feet of cover. Then you’re talking about a seven-foot excavation. It couldn’t be done without cutting the frost.”

Rockwheels: not just for rock

At first, they tried a bulldozer with a ripper attachment, but the ripper was unable to penetrate deep enough and score the ditch adequately to where crews could then excavate. They had also contemplated using a traditional trencher or ditch machine, but decided against it because the equipment’s bulkiness and heavy weight prevented it from being easily moved from location to location.

That’s when Jinkerson and Walters took another look at the company’s arsenal of equipment and settled on the Vermeer RTX1250 quad-track ride-on tractor with a rockwheel attachment. “Henkels has several of these machines in its equipment fleet, but none of them were available when we needed them, so we had to rent all of them,” Jinkerson says.

Rockwheels are typically used to cut rock, but Jinkerson hoped the attachment would work just as well on frozen soil. All they needed was for the rockwheels to cut the ground deep and wide enough so that they could then excavate. Capable of cutting rock in depths up to 40 inches and widths ranging from 4 to 12 inches, the machines’ shank rotary carbide teeth help increase cutting performance in tough conditions.

“The rockwheel is thin, so we had to make a couple of passes with it. It would open up the trench, and then we would clean the trench with the excavator and obtain our required depth requirements,” Jinkerson says.