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    Credit: Rick Zettler

    Fire in a cell lined with shredded tires generated 40,000 square yards of debris for the Iowa City Landfill and Recycling Center in Johnson County, Iowa. Water won’t extinguish burning tires, so heavy machinery was brought in to level and cover the smoldering piles of material with clay.
 

Renting vs. contracting

For years, Hansen has rented equipment to fill the needs of Iowa City and the landfill.

“The city rents endloaders during winter to supplement the existing fleet for snow removal,” says Dan Wiley, rental account manager for Titan Rentals in Center Point, Iowa. “They also rent specialty equipment for projects where they can’t justify the capital expenditure.”

Using the lowest per-month rental cost for each machine, Hansen distributed a bid request for five pieces of equipment to four local distributors, sizing the haul trucks to match the size of the excavator and estimating that 40,000 square yards of material would have to be removed:

  • One 45-ton tracked excavator
  • One 4,000-gallon water truck
  • One 17.5-ton bulldozer
  • Two 30-ton articulated haul trucks.

When Titan Rentals received the request, Wiley got an idea. The company had just taken delivery of new Terex Corp. TA400 articulated haul trucks, which have a maximum payload of 41.9 tons. Using two of them instead of 30-ton trucks would cut the number of trip cycles and time on the job by at least 25%.

Titan Rentals’ bid solution was accepted, and the two trucks were put into commission in early August for two months. They were matched to a Caterpillar 336E excavator equipped with a 3.06-square-yard bucket from Caterpillar dealership Altorfer Rents.

The landfill then posted help wanted ads on Iowa City’s website and in the local paper seeking temporary equipment operators (see sidebar on page 28). Skilled laborers who were between jobs at the time responded.

Each truck carried six to nine buckets of debris. Their ability to climb grades while fully loaded was essential. “It’s like working in the bottom of a bowl,” says Hansen. “The trucks are climbing 3:1 and 4:1 grades.”

The TA400 is able to manage such slopes because of an all-wheel, 6 by 6 drive with automatic limited slip differentials in each axle. Heavy-duty axles with full floating shafts allow independent wheel movement to navigate irregular terrain and improve ride. A three-stage selectable engine braking system and six-stage selectable output transmission retarder improves control during downhill hauling.

The trucks hauled both charred tires/ash and soil/gravel to different sections of the landfill.

“We hope to reuse the soil and gravel for cell rebuilding,” says Hansen. Round-trip times depended on material: about eight minutes for tires/ash and four minutes for soil/gravel. The trucks’ two-speed drop box transmission that lets the operator select rim-pull for tackling very steep grades or reach more than 34 mph on level runs lowered cycle times further.

Hansen wasn’t dissuaded by the vehicle’s 331-hp Tier 4 interim diesel engine, having learned they’re more fuel-efficient than Tier 3 models.

“Some customers shy away from Tier 4i engines because of the need to add diesel exhaust fluid (DEF) to the tank, but we already had a great deal of experience with them,” says Hansen. With many pieces of the fleet’s construction equipment and some busses requiring DEF, he’s looking at buying two, 250-gallon storage tanks. The Terex truck’s 13.7-gallon DEF tank requires topping off after every other filling of the vehicle’s 130.5-gallon fuel tank.

With debris removal complete, managers have rebuilt the cell. What may come as a surprise to some, they reconstructed the leachate system with shredded tires once again. But they’re slightly modifying the design: installing the tires in segments versus lining the entire cell at one time.

—Rick Zettler (zcomm@mchsi.com) is a freelance writer and photographer who specializes in the waste, construction, and aggregate industries.