Milling Up Missouri

Depending on their driving habits, motorists in the state of Missouri have probably been noticing one of two things. Alert drivers are likely seeing construction crews operating cold planer milling machines on highways, removing old shoulders to make way for new. Sleepy or inattentive drivers may not be catching any of the actual construction, but might be experiencing the occasional awakening jolt from the freshly stamped rumble strips that have been added to those new shoulders.

This type of road repair work is very common today throughout the Midwest. In some cases, highway shoulders remain solid enough that rumble strips can be added to the existing asphalt surface. But far more often, thin pavement layers have rendered shoulders susceptible to deterioration. The only option in such situations is to mill the shoulder out and put down new asphalt in its place.

APAC Missouri is one contractor that’s bid its fair share of projects involving the addition of rumble strips to highway shoulders across the state. One of the leading construction groups in the region for more than a century, APAC Missouri operates its own quarries and asphalt plants, in addition to running asphalt paving crews. The company currently employs 120 people out of its Springfield, MO office alone.

“There’s a lot of this construction going on in Missouri right now,” says a spokesperson for APAC Missouri. “We’re removing two-, three- or four-foot sections of shoulder, putting back new mix and then adding rumble strips. We had enough work going on at one point this past summer that we were running nine different milling machines, including those in our fleet and some we rented.”

Renting made sense

One of those rentals came about as the company was preparing to tackle three different milling projects requiring a 4-foot mill in July 2012. Facing a fairly tight production schedule, APAC Missouri connected with the G.W. Van Keppel Company and arranged a 30-day rental of a BOMAG BM1200/30-2 cold planer milling machine.

Powered by a 275-hp Caterpillar diesel engine and featuring a centrally mounted cutting drum for enhanced stability, the BM1200/30-2 offers a 47.2-inch milling width and is capable of milling depths up to 12.6 inches.

“We needed a 4-foot mill in short order, and the availability and price was right, so we went ahead and rented it,” says APAC Missouri.

The primary job for the milling machine involved removing portions of the shoulder — 4 feet wide and 3 inches deep — for 30 total miles along both the northbound and southbound lanes of U.S. Highway 65, between Springfield and Fair Grove, MO. Approximately 10,000 tons of asphalt was to be removed, which the company, in turn, was planning to use for general fill material at another location.

“Our bidding process required us to achieve certain tonnage milestones on a daily basis,” says APAC Missouri. “As it turned out, the machine actually delivered a higher production rate than we had hoped for. We got very consistent production, and were able to complete the whole job in just six days.”

The average milling rate achieved by the milling machine on the Highway 65 job was approximately 90 feet per minute. The machine’s efficiency also enhanced the efforts of the rest of the APAC crew on the jobsite, who followed behind the milling progress with a road widener and two tandem rollers to rebuild the shoulder.

“The BOMAG ran very smoothly,” added APAC Missouri. “It was a new mill that hadn’t been broken in yet, so there were some minor adjustments that needed attention. But Van Keppel provided us with great support and service. They’d take care of everything in the evening so we were always ready to run first thing in the morning.”

After the Highway 65 job, the BM1200/30-2 moved on to its next task, full-depth removal of shoulders on U.S. Highway 60 in Republic, MO. Just as had been accomplished on the previous project, APAC Missouri tackled the job without a hitch, removing 1,500 tons of asphalt in two shifts.

Removing rumble strips

The third and final job for the milling machine was a significant departure from the first two. This time, rather than milling along highway shoulders for miles at a time, the assignment was to remove patches of stamped rumble strip from the driving lanes of U.S. Highway 160. Furthermore, the milled patches happened to be concrete, not asphalt. Accomplished in four shifts, the project comprised of 400 total patches removed, each of them 4 feet wide and 6 feet long.

The contractor came away extremely pleased with the performance and versatility of the mill. “It did exactly what we needed it to do,” says APAC Missouri. “We were impressed by the machine’s productivity and how efficiently we moved through each job while we had it. And the operators absolutely liked everything about it. They weren’t happy when we sent it back off rent.”

Among the features that stood out to APAC’s operators was the visibility afforded by the operating platform being located directly over the cutting area. Additionally, the operator’s seat can slide out over the right edge of the machine, providing excellent vision of the cutting drum’s leading edge.

Overall control of the BM1200/30-2 was another benefit to the production schedule. The mill features user-friendly displays and controls, including INTELPLANER automatic milling depth control. The machine also includes four-track stability with front and rear steering that can be operated independently or coordinated as needed.

“The maneuverability of the machine was outstanding,” says APAC Missouri. “Between that and being able to always have a clear view of the work area, it really led to a great combination of consistently precise milling and fast, efficient operation.”

Crews using the milling machine also appreciated that the front-loading conveyor was foldable, simplifying transport to and from each jobsite. “The machine is the correct size that we could move it on our standard trailers,” added APAC Missouri. “Sometimes we have to use a mill from our fleet that’s larger than what we need, and because of the added size and weight we need to buy permits and use a special trailer. The ease of mobility in moving from one job to the next was a welcome benefit.”

With the BM1200/30-2 having passed its one-month test, APAC Missouri says that purchasing the machine is definitely an option they’re considering, should workload dictate that the 4-foot mill be permanently added to the company’s equipment fleet.

In the meantime, as another season of road repair and construction begins, Missouri motorists may want to strongly consider the option of staying within the lane lines — and not testing the rumble strips becoming more and more common on the highway shoulders.