In Missouri, rigid-frame trucks are usually associated with rock work, not dirt work. Rain turns dirt to mud and clay, and conventional thinking says, “Use articulated trucks” if there’s any possibility of moisture.
But Hilty Quarries was bidding a 2.8-mi. (4.5 km) MODOT State Highway 13 road-bed project, and it really wanted to use rigids because of their usefulness post-project at its various quarries. So the Hilty Quarries turned to the G.W. Van Keppel Company for advice.
“We bought our first new crushing plant from Van Keppel back in 1972, so we have an excellent, long-term relationship with them,” said John Hilty, secretary-treasurer, of Hilty Quarries. “When we discussed the project parameters, our need to move 8,000 yards a day, and our concern over the use of rigids, they contacted Hitachi and asked for an engineer to do an on-site survey,” he added.
Hilty Quarries is no stranger to Hitachi products. In 1974, it bought two R13 Euclid trucks, which it still own today. Over the years, the company added seven R25s and four more in the 35- to 40-ton range. In 1985, it bought a Hitachi UH122 excavator, one of the first ever sold by Van Keppel, and then followed up over the years with an EX200, 230, 270, and 450.
“The dirt haul road is a long one, with the borrow pit about two miles away,” related Brian Mace, the Hitachi engineer who visited the site. “The haul road itself is pretty flat, except for one hill. They keep the road well maintained, which is a critical point. The soil is loamy dirt mixed with clay, and it gets soft and slick when wet,” he added.
Using Hitachi’s CONSULT program to compare ground pressure and other variables, plus relying on his own years of experience, Mace determined the rigids would perform fine. “We’ve got larger trucks than the EH700 doing a great job in soft ground conditions at the Oil Sands in Canada and at the coal mines in southern Indiana,” said Mace. “I knew they’d do fine.”
Hilty Quarries chose to buy a Zaxis 800 excavator to work in the borrow pit and four new EH700 rigid frame trucks to haul the road base material to the construction site. The company has used scrapers in the past, but the use of an excavator would allow for the faster removal of material. It also could foresee using the 800 in other construction and quarry applications.
“The depth of the material varies along the length of the project, especially as it nears embankments, but it averages about 12 feet above grade,” said Hilty. “Part of the road-bed project includes the south embankment of a railroad overpass and both embankments for a county road overpass.”
According to Van Keppel, the Hitachi excavator/truck combo has worked very well on the current State Highway 13 project. The roundtrip takes between nine and 10 minutes, and with the four trucks, there has been virtually no waiting. “Hitachi makes good products,” stated Hilty.
The workday is 10 hours, and so far, everything is on schedule. As the length of the haul road increases, some additional trucks may need to be taken from Hilty’s extensive Hitachi rigid truck fleet to maintain the pace.
Hilty Quarries is serviced by the G.W. Van Keppel Company, Kansas City, KS.
(This article appears courtesy of Hitachi’s “Breakout Magazine.”)