The Muck Stops Here
The process of ensuring soil stability in major Minnesota highway expansion is made simpler with machine control
There are companies for whom GNSS-based solutions are a welcome addition, a good way to streamline the workflow, even a great means to bolster the bottom line. Then there’s Mathiowetz Construction. The Sleepy-Eye, Minnesota-based contractor has embraced the technology to such a degree that to perform without it seems counterproductive. Case in point: an ongoing mucking operation to replace sub-standard soil with better, more structurally sound material on a south central Minnesota highway project. There, machine control is present, not just on dozers, motor graders and scrapers, but also on the excavators spearheading the actual removal of more than 300,000 cubic yards of material. Drawing upon that solution has resulted in all the benefits mentioned above and helped eliminate a potential bottleneck on the operation. For Mathiowetz, without a doubt, it was the hole solution.
Filling the Gaps
Trunk Highway 212 is a key east-west artery linking the Twin Cities of Minneapolis-St. Paul with numerous towns and businesses in western Minnesota and eastern South Dakota. In early 2021, the State of Minnesota and Carver County broke ground on a $27.8 million project to widen several sections of the highway that were still two-lane roads. Doing so will improve safety, increase the efficiency of freight movement, and implement the state’s end-to-end, four-lane vision for Highway 212. The project is both needed and timely, according to Brett Mathiowetz, the company’s executive vice president.
“I think we are already seeing some of the effects the pandemic is having on this area,” he said. “More people are moving out of The Twin Cities and into some of the smaller surrounding towns such as Cologne, Norwood/Young America and others. When 212 is complete, those who have moved will have a much easier commute to jobs downtown. However, for those who have made major career or job changes and are working in southwest suburbs like Edina, Eden Prairie, Chaska or Chanhassen, this will be an even bigger plus.”
Highway 212 is also a key corridor for commercial traffic, handling over three million truck miles annually — more than double the volume of a typical state highway. Improvements to a full four-lane system will reduce truck delays which, according to MnDOT, are currently costing shippers of goods up to $275,000 a year.
“At certain sites we’ve brought sand up to the existing grade, installed wicking drains to help remove the moisture beneath and then placed surcharge material atop it all to aide in the soil prep process.”
Having done a number of major highway improvement projects for the state, the Highway 212 job was fairly straightforward work for Mathiowetz Construction — and well within the realm of their capabilities. Even the fact that they’d have to perform a mucking operation in several areas was not out of the ordinary. What did cast a different light on the project, however, was the severity of the work needed in some areas to make the road happen.
For those unfamiliar with the term “mucking,” simply put, it is the removal of unstable — usually wet — soils and replacement with material that will support the future roadway. According to Mathiowetz, soil boring samples, taken in advance of the project, generally dictate where such action is needed to be taken.
“The goal of taking borings is to determine the types of soils, what kind of structural stability is provided, and what moisture is present,” he said. “However, borings are only done at intervals at a site and no one can predict what’s happening in between each boring, how varied it might be. As a result, we have encountered areas in which we thought we’d only need to excavate down six or seven feet and ended up going down past 20 feet — even into the low 30s. But that, too, is just part of the job.”
Getting Down to Business
Veterans to this type of work, Mathiowetz Construction has seen a dramatic change in the manner in which mucking operations are performed, verified and recorded. Once done using a plumb bob suspended down into the hole and a tape measure to verify the distance to existing ground, today’s project is rife with technology designed to improve accuracy, minimize labor and ensure accurate reporting. For Mathiowetz and his crew at the Highway 212 project, each excavator contains everything needed to bring all those to fruition.
“We have been proponents of GNSS technology from Topcon Positioning Systems for over two decades now and run 30+ systems on our equipment company-wide — more than a dozen at this site alone,” he said. “Our excavator operators are using either the Topcon X-53 or X-53i solution on their machines and getting outstanding results. Having the ability to know precisely where their bucket is positioned eliminates a continual need for grade checking; that’s really key to keeping production levels up. Dan Weise and the crew at RDO Equipment have been our partners in this whole journey toward automation and we can’t say enough about the level of support we receive.”
While the systems in place on Mathiowetz’s machines are designed to provide differing levels of control — from 3D machine control to indicate-assistance — each is centered around precisely reaching target grade and minimizing the risk of over-excavation.
“We have been proponents of GNSS technology from Topcon Positioning Systems for over two decades now and run 30+ systems on our equipment company-wide — more than a dozen at this site alone.”
Quantity and Quality
Just as the means by which Mathiowetz verifies surface elevations have changed over the years, so too, has the methodology for determining quantities removed. What was once a time-consuming part of the job, prone to disparity, is now fast and accurate, said Mathiowetz.
“In the past, quantity info could differ greatly, depending on who was gathering it,” he said. “There was often a good deal of negotiation needed to reconcile figures that could be off by as much as 25-30,000 cubic yards. Today, we use Sitelink3D, a site management solution from Topcon that provides a continual stream of information from the machine — including how much material has been cut, where we are working, and the quantities moved. From there, in real-time, it is automatically uploaded onto a web portal where we, the county or the state can access it as needed.”
Although a consultant still checks the surface and compares quantities with Mathiowetz’s team, the process — that used to take hours — is now being done in minutes. “And, at the end of the day, we are generally within a couple of hundred yards on 150,000 yards of material,” he said. “That accuracy and convenience, coupled with the lack of strain on the relationship with the parties involved, is a very big deal.”
Seen in its entirety, the mucking operation is a finely-orchestrated ballet of soil excavation, a non-stop stream of 8-10 articulated off-road trucks hauling the spoils out, highway trucks hauling new material back in, and dozers pushing it into place.
Not all areas deemed to be less than structurally sound are slated for a full mucking operation. Anything that falls outside the core area of the road — shoulders for example — can be left alone. Other areas in which full-depth excavation to ideal soil is not feasible are excavated only to a specific design elevation and treated in a different way.
“At certain sites, we’ve brought sand up to the existing grade, installed wicking drains to help remove the moisture beneath and then placed surcharge material atop it all to aid in the soil prep process,” said Mathiowetz. “Once it is done settling out, we remove the surcharge material and complete the road. In another area, a full-on dewatering effort was needed — it is definitely not a ‘one-approach-fits-all’ effort out here.”
The Kids Are Alright
Despite Mathiowetz Construction’s fairly rural location — midway between Minneapolis and Sioux Falls, South Dakota — the company has had great success recruiting new help as people move on or retire. The fact that they are so technology-heavy has not hindered them at all, said Mathiowetz.
“We have a veteran operator named Francis “Franny” Helget who has helped us mentor a whole generation of new operators,” he said. “The new kids coming into the business today grasp the solutions quickly which helps them grow faster over a shorter period of time. But while technology makes everything easier, it can also cause a person to want to short-cut learning how to use the machine. So, we are always trying to coach people not to totally rely upon the machine to do everything — but it’s tempting with everything right there at their fingertips.”
By project’s end in the fall of 2022, Mathiowetz Construction will have moved more than one million cubic yards of soil — including the sand and aggregate used in the various parts of the mucking operations.
“This has been a great job made even better by the solutions we bring to the job every day. But we have also been blessed with some of the best people working today. Construction is a challenging environment and certainly not suited for everyone, but I really feel we have the best of the best, both in people and technology.”