Suspended judgment
June 1, 2006 By: Mary McCaig-Foster Pit & QuarrySuspended haul truck dump bodies increase capacity and eliminate the headaches associated with traditional bodies.
In 1989, when Stone-Street Quarries of Fort Wayne, Ind., sold its interests to Rockville, Md.-based Rockville Crushed Stone, the Indiana quarry was sorely in need of new haul trucks. At the time, because Rockville Crushed Stone was updating its fleet, Rockville's management invited Stone-Street Quarries operations manager Waine Phillips to choose a couple of trucks from the Maryland fleet. The consensus was that Rockville's trucks were several years old, but they still would be an improvement over Stone-Street's trucks at the time.
"I went to Rockville, picked out a couple of Cat 769 (35-ton) trucks, and came back to Indiana," Phillips says. "But when the trucks were delivered in early 1990, my first thought was that I'd been given the wrong trucks."
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The cabs and chassis looked right, but the beds looked like nothing Phillips had ever seen. "Picture an open truck bed frame, with a bunch of rubber bands holding up rubber placemats, and that's what I saw," Phillips says. Upon inspection, he realized the trucks were the same models he had chosen, but Rockville Crushed Stone had switched the bed frames and beds for a style of dump bed that even today is a new concept for producers in North America.
According to Phillips, he simply put the trucks to use. "I figured the beds would wear out quickly, but what else was I going to do?" he asks. Then he did some research.
 Stone-Street Quarries, Ft. Wayne, Ind., produces 6,000 tons per day, using a 3042 primary jaw, a 5.5-ft. secondary and 4.5-ft. tertiary cone. |
The truck bed frames and liners are manufactured by an Australian company called Conymet Duratray Pty. Ltd. (Duratray). The truck bed design is Swedish in origin. At the time Phillips received his Cat 769s with the retrofitted beds, Duratray was a part of Pacific Dunlop. Conymet bought Duratray in 2001. Duratray opened its North American Operations in 2005, based in Austin, Texas.
Stone-Street's Cat 769s were 10 years old when Phillips took delivery of them in 1990. The Duratray beds and liners had been manufactured in 1987. "I learned that Rockville Crushed Stone had some other trucks with these Duratray beds and liners, but they wanted all-steel beds. They hadn't used these beds very long and didn't know much about them, so they switched the beds before they delivered our trucks," Phillips says. "Their loss."
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Big benefits
It didn't take Phillips long before he began to see the benefits of the new bed style. The fact that the liners are held in place by rubber "ropes," as thick as a man's forearm, which are suspended from a heavy-duty steel frame, allows the entire truck bed to remain flexible, and in slight, constant motion. This feature virtually eliminates material sticking, even in winter when most truck beds experience material freezing.
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