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Quarry Quandary

Posted By Therese Dunphy On February 1, 2010 @ 12:53 pm In Applications,Articles,Featured Articles,Features | No Comments

A high-production excavator keeps Oahu quarry development on schedule.


App-AM0210-GR-518962 [1]Fifty-ton haul trucks scurry about the new quarry being established by Grace Pacific Corp. on the Hawaiian island of Oahu. Like ants from a pile of honey, they scurry from the loading excavator, one every minute and 20 seconds, their beds heaped high.

Bob Singlehurst, project manager of this huge venture, looks down on the activity from his lofty vantage point with a knowing smile. “We have 6 million cubic yards of material to move to get this site ready,” Singlehurst says. “The production we’re getting from the EX1200 is keeping us on schedule.”

The excavator’s 6.9-cubic-yard bucket fills quickly as 115,081 pounds of digging force rips through the volcanic material, cycle after cycle.


So what’s the hurry?

Time is money. The owners want the prep work done before the necessary operating permits arrive. Overburden must be removed, haul roads cut into the walls of the quarry, and berms built to shield the 35-acre project from view. Once in operation, more than a million cubic yards of rock a year will be mined for the next 25 years. It’s a big job, one of the largest this 69-year-old veteran of the quarry business has had in his storied career.

“The company has an enormous investment here,” Singlehurst says. “We need to be ready to produce as soon as those permits arrive.” He has never had a non-American-made machine in one of his quarries until now. His regular excavator manufacturer didn’t build a machine big enough for this job. “We tried the Hitachi and have liked it from the beginning,” Singlehurst says. “Now that it’s been on the job a while, I would honestly say the EX1200 has exceeded our expectations in every way.”


Dependable support

Singlehurst talks, too, of the importance a dealer plays in the selection of equipment: “A good dealer is particularly important when you’re dealing with a high-production machine. If it goes down, the job and all of the men and equipment working with it go down, too.” He notes that costs soar far higher than the repair bill itself. Dealers need to have competent technicians and well-stocked parts departments.

“We’ve had virtually no downtime… but when there’s an issue, the repair truck is here in an hour or less,” Singhurst says. “And there has been nothing that has stumped the technician. He’s been able to get us going fast.” The project manager does allude to one instance when the machine was down for a day. It seems a tooth ripped off the bucket, and to get it welded correctly just took time.

It’s important to have a competent dealer, particularly when working in a remote location like Hawaii can cause difficulties when parts are needed fast. Singlehurst says that this hasn’t been a problem. “American Machinery has had any part we’ve needed in stock.” He also points out that with today’s airfreight, parts can arrive in a couple of days.


Creature comforts

Operator comfort, particularly in a high-production machine, can help an operator work at peak efficiency for long shifts, and this machine stands tall on this measure, too. Large tinted-glass panels provide a clear view, 360 degrees around. A fully adjustable suspension seat molds to the operator’s body for total comfort, and the cab is heated, air conditioned, and fully pressurized to keep dust out.

“I’d have to fight to get that machine away from our operator,” Singlehurst says, “And, I’m not sure I would win.” He points to another area where a happy operator pays big dividends — the way the machine is operated and taken care of. He notes that pride can go a long way in increasing production and reducing abuse of the machine.


Back on the job

The seemingly unending stream of haul trucks continues to snake through the winding quarry roads as the 760-horsepower excavator swings smoothly, rock to truck, rock to truck, rock to truck. There’s quiet confidence that this huge project will be ready on time and on budget. “We couldn’t do it without the EX1200,” Singlehurst says.


 About Grace Pacific Corp.:

This 75-year-old company has constructed and maintained the roads and highways that are an integral part of Hawaii’s infrastructure. Besides being the state’s premier concrete, asphalt, and aggregate supplier, its 500 employess provide prestressed and precast concrete products, metal framing systems for construction, and traffic and highway safety products.



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