A close-up of the 190-ft. TeleStacker, the largest of its kind on the market. Kimball Sand Co. chose the unit for its high-volume stockpiling and rugged build.

If just for the fuel cost savings alone, stockpiling with an automated conveying system, rather than loaders, is a quantum leap in material handling methodology. A frustrating reminder, but diesel fuel is well over the $4-gallon mark, up a staggering 125 percent over a year ago, and the price is still rising. Worldwide demand is putting more pressure on tight global refining capacity, and, in the United States, the transition to low-sulfur diesel fuel has affected production and distribution costs. Plus, the federal excise tax on diesel fuel is higher per gallon than the tax on gasoline.

It was nearly two years ago when Blackstone, Mass.-based Kimball Sand Co. Inc. took its loaders off stockpiling duty, replacing them with automated telescoping radial stacking conveyors. "We had been operating with stationary conveyors and always had to bucket material and build stockpiles with loaders, and we were burning way too much fuel," said Maintenance Manager Scott Kimball, whose operation purchased four 190-ft. TeleStacker conveyors manufactured by Superior Industries. It was an investment Kimball said netted a quick return and resulted in benefits far beyond that of fuel savings.

First, Kimball points to the wear and tear on the loader when used in stockpiling. The operation needed to limit loader operation to level applications and loadout use, as loader component and tire wear accelerates when operated on inclines exceeding 6 percent.

To minimize costly loader use, Kimball Sand Co. uses 190-ft. TeleStacker conveyors for cost-efficient, high-volume, multiple-product stockpiling.

"It is major abuse to the transmission to climb up and down a ramp all day while building and maintaining a stockpile," he said, adding that there is considerable time and labor required to berm the stockpile to meet MSHA requirements. With conveyor systems in place, there is no need to gain access to the top of the stockpile. Furthermore, the company can maximize the investment made in its two loaders by using one to loadout trucks, and keeping the other available as a "utility hitter," doing jobs such as feeding overburden into a portable screening plant.

The cost of mobile equipment

Studies indicate that lifetime (8,000 to 12,000 hours) loader owning and operating costs are no less than 2.25 times higher than the unit's initial purchase price, and that figure does not even include labor, driver training, emission fees and fuel costs. When one looks at annual data based on 2,500 hours per year and 500,000 tons of material handled, loader operating costs are nearly 12 times higher than the cost of operating a TeleStacker conveyor in a stockpiling application, according to Superior Industries. Therefore, proper equipment utilization is a key to greater cost-efficiency.

Next, Kimball eliminated the additional material-handling costs of the prior stationary conveyor setup. To run a different product, the operation had to move the current material out from under the conveyor belt. "We'd have to shut down for two days, have two loaders bucketing material, moving it a few hundred feet away, making a ramp and building a new stockpile. Now we are able to feed material to the crusher and it remains untouched until it's loaded on the truck and heads down the road," he said.

Plus, the operation can deliver a clean quality product. Loader stockpiling causes contamination and compaction. "If you've just washed the stone, you certainly don't want to track mud onto the pile," Kimball said.