Aggregates can serve as the foundation of the construction industry, given the large role they play in projects of all types.
According to the United States Geological Survey (USGS) in 2008, the most recent year for which statistics are available, 1.58 billion tons (1.44 billion t) of crushed stone was produced for U.S. consumption, almost 13 percent less than the total for the previous year. Even so, its value was more than $13 billion. A mineral commodity summary from the Geological Survey noted in January 2010 that crushed stone is the leading choice for construction aggregates.
Whatever the amount, loading the material for transport requires systems specially designed to fit individual circumstances.
Family owned for more than a quarter century, Kemper Equipment Inc., of Honey Brook, Pa, designs such aggregate handling systems, often of such complexity they could well be compared to enormous mouse traps similar to the well-known game manufactured by Milton Bradley.
In addition, Kemper Equipment not only distributes manufactured aggregate equipment from major suppliers and provides parts and service for most makes and models of quarry and mining equipment, it also manufactures custom conveyors, hoppers, bins, support structures, and similar equipment in its 30,000 sq. ft. facility in Hazleton, Pa., for erection on a client’s job site.
With more than 3,000 projects completed in the mid-Atlantic region since 1980, the company recently worked with Carmeuse Lime and Stone to design a 3,500 tons (3,175 t) per hour (TPH) rail load out system for its Middletown, Va., site. The system features nine conveyors moving 3,500 TPH of various sizes and specifications of limestone and basically processes and sorts the material, which is then specifically blended for final use by power plants.
Adding on to the existing 4248 jaw plant already at the location, Kemper supplied the majority of pieces for the rail load out system, including all conveyors leading to a Simplicity scalping screening closed circuit to a 54 ft. (16.4 m) El Jay cone crusher. The product continues to a Simplicity 3 deck finishing screen, then travels on a new tripper conveyor to multiple stockpiles that make up a nine station surge pile.
The surge pile is depleted using a tunnel over 12 ft. (3.6 m) in diameter and nine feeders with variable frequency drives to give infinite ability to blend various mixes of limestone. This final custom-blended product is supplied to power plants to be used as a scrubber material for cleaning purposes and is conveyed from tunnel to a custom-designed belt line, which moves blends to the rail car tower provided by the Kanawha Manufacturing Company of Charleston, W.Va., and is loaded onto rail cars for distribution.
Headquartered in Pittsburgh, Pa., Carmeuse Lime and Stone is a leading North American producer of limestone and lime products. With more than 30 manufacturing facilities in operation, it produces approximately 6 million tons (5.4 million t) annually of lime products as well as 25 million tons (22.6 million t) of chemical limestone and aggregates each year.
The quantity of material Carmeuse Lime and Stone routinely handles on its Middletown site alone is indicated by, for example, the presence of stockpiles of crushed stone, some rising as high as 75 ft. (22.8 m).
“Carmeuse is a repeat customer of ours,” said Greg Donecker, president of Kemper Equipment Inc. “They use our conveyors at various locations, plus we have supplied them with a complete crushing and screening plant, recrush circuits, surge reclaim systems, and other conveyor systems in the past.”
“The scope of this job required intense pre-planning and coordination prior to manufacture and supply,” he added. “Advance planning included pre-assembled conveyor drive packages completed at our shop in Hazleton, Pa., for easy installation on the site.”
A particular challenge facing Kemper was Carmeuse’s requirement that the system include an option of handling multiple end products. Thus the equipment had to be capable of blending different materials. Kemper Equipment met the challenge with a customized system of conveyors and feeders.
The industrial division of York, Pa.-based general contractor Kinsley Construction Inc., also worked on the project.
Founded in 1963, Kinsley is a family-owned business originally operated as a concrete services subcontractor. Since the 1970s, the company has provided general contracting services, including construction management and design/build assistance
“We self-performed 2,500 yards of concrete placement, partial fabrication, and erection of new equipment and steel,” said Rick Johnson, senior estimator.
“We had 35 to 40 employees on site, who worked for a total of 41,000 man-hours during the erection of the new 2000 conveyor. We used Manitowoc and Liebherr cranes, Caterpillar earthmoving equipment, and JLG aerial lifts for the job,” he added.
Kinsley began work on the $5.5 million contract on June 26, 2009, and with no significant problems completed it on Jan. 30, 2010.
“We have been doing work in the aggregate business for the last 10 years with revenues in this market sector varying anywhere from $5 to $15 million a year,” Johnson said. “In this case, the system was installed to load train cars with an aggregate that is used as a filter media. The system loads 10,000 tons of aggregate into 100 train cars in six hours.”
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