Aggregates Manager

December 2013

Aggregates Manager Digital Magazine

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Page 17 of 88

EQUIPMENT MANAGEMENT operation of diesel engines without antifreeze has shown cylinder liner pitting to perforation. Struts The suspension cylinders, or struts, are charged with oil and nitrogen. Check strut pressure at least every 500 hours or three months. Improperly charged struts will result in reduced tire life, uncomfortable ride and poor handling, and even reduced frame life and accelerated component wear. See the O&M manual for proper checking procedures. Frame and body A thorough frame and body inspection should be performed at least every 1,000 hours or six months. Thoroughly washing the truck is the first step to enable an inspector to see cracks. If repairs are needed, consult your dealer for repair procedures. Proper weld repairs may be needed to stop further cracking and to avoid high cost failures. Regularly washing quarry trucks pays other benefits, too. In addition to spotting cracks, inspectors can more easily identify leaks, loose fasteners, and other problems. And a clean truck won't carry the dead weight of dirt and mud that burns more fuel as it is transported around the quarry. Also, accumulations of mud can contribute to overloading, which prematurely wears all components. Tires Daily tire inspections are recommended, while tire inflation should be checked every 50 operating hours or at least weekly. Always obtain the proper tire inflation pressure from your tire supplier. Low tire pressure can be hazardous, because it affects truck steering and braking. Additionally, low inflation pressure reduces load-carrying capability, allows the tire to heat up quickly, and increases rolling resistance. The result is accelerated tire wear and higher haulage costs. Caterpillar offers the Ton Mile per Hour (TMPH) Tire Monitoring system on quarry trucks. This program takes the payload value from the Cat Truck Production Monitoring System onboard, combines it with ambient air temperature, machine speed, and the manufacturer's TMPH rating for your tires and calculates tire condition continuously. As a tire approaches its temperature limits, the truck operator gets a warning inside the cab. Such systems can be an important tool in your efforts to extend tire life. Of course, the tires in a dual tire configuration should be the same brand, the same type, and the same construction. The 16 AGGREGATES MANAGER December 2013 tires also should be the same designated size and have the same amount of wear to minimize overloading of a single tire and undue stresses on the drive train. Routine truck maintenance, condition monitoring through fluids analysis, and the right approach to operations is the route to getting the most out of quarry trucks. Do the right thing, and higher productivity and lower costs will result. AM Mark W. Sprouls has worked with and within the mining industry since 1974 and now writes about mining equipment topics for Caterpillar Inc. He is based in Tucson. The optimum load The weight of the load and location of material in the truck body has a direct effect on productivity, cost, and mechanical availability. Also, truck steering and braking can be affected by overloading and poor placement of the load. Caterpillar offers its 10/10/20 Payload Guidelines to help optimize truck component life and mechanical availability: the target payload of the truck. target payload by more than 10 percent. target payload. Payload monitoring systems can help loading machine operators optimize truck payloads. The Cat Truck Production Monitoring System has indicator lights on the truck to indicate to the loader operator when a last pass is needed and when the truck is fully loaded. The system also stores data for later analysis. Data includes payload weights, haul cycle times, and distances — all with date and time stamps. In addition to loading the right weight onto a truck, the goal is to place the material so that one third of the weight is on the front bodies, the center is the hoist cylinders, but some bodies may require center markings to guide the loading machine operator. Longitudinally, the load should be centered on the centerline of board, and there should be enough freeboard to minimize spillage from the sides and the rear. Avoiding overloading and locating the load properly in the body contributes to truck safety and long component life, and it helps achieve low haulage costs.

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