Aggregates Manager Digital Magazine
Issue link: http://read.dmtmag.com/i/452309
AGGREGATES MANAGER February 2015 28 on the truck. Tailgates optimize the loading zone by pro- viding a better target so loaders can dump materials in the middle of the body, rather than near the front, improving weight distribution and overall truck stability. Without the added benefit of the tailgate, loader-operators avoid spill- age by placing most or all of the materials toward the front of the bed. This loading technique ends up overloading and stressing the front axles and hydraulic hoist cylinders of the truck, resulting in premature tire wear, body main- tenance, and potential axle and hoist cylinder damage. Typically, rigid-frame haul trucks are designed to carry one-third of the weight on their front axle and two-thirds on the back. Dumping heavy materials toward the front puts immoderate stress on the chassis, axles, front tires, sus- pensions, and hydraulic systems. Front tires only support so much weight before they blow or rim damage occurs. Sometimes tires can be salvaged, patched, or re-treaded, but even repairs are expensive, costing up to 60 percent of their original cost. An optimized loading target, equal- ized weight distribution, and reduced spillage means that trucks with tailgates can extend a tire's service life by as much as 40 percent or up to 13,000 hours in some cases. It's important to remember that just because a truck has a tailgate, that doesn't mean it can be overloaded. A 70-ton truck cannot haul 80 tons of material without operating outside of the OEM truck manufacturers guidelines; this can cause damage and safety hazards in addition to void- ing the truck warranty. Squeezing an extra 10 tons in a load might seem like a quick way to bring in extra prof- its; however, repair costs far exceed the additional reve- nue if you blow a tire or cripple the chassis and axles. Minimize maintenance Maximizing payload capacity and reducing tire and axle wear are only two of the financial factors to consider. The benefits of adding a tailgate may extend beyond the truck to haul roads and the other equipment working in prox- imity. Anyone who spends their day in a mine knows roads can be narrow, rough, and littered with spillage, which makes them hard to navigate and poses risks to the trucks and other equipment operating at the site. All options for dealing with the challenges result in lost time or increased expenses. Closing haul roads to clear the debris means lost productivity and the costs associat- ed with the fuel and labor and downtime for cleaning. Navigating the debris can damage tires, as well as the truck's suspension systems. In some large mines, more than 200 tires are replaced per month because of debris damage or overloading. Many businesses aren't equipped to handle the negative impact that has on the overall profitability, especially since the cost of rubber has gone up by 250 percent since 2009. Most mining truck tires cost upward of $10,000 each, with some larger models topping out at $100,000 each. Combine those extra costs with downtime caused by the repairs and replacement, and the impact can be devastating. A global tire shortage for mining-class vehicles only compounds the problem with longer-than-nor- mal wait times just to receive replacement tires. What options are there? It doesn't take long to put pencil to paper and figure out that adding a tailgate enhances profitability, but the de- cision is not that simple. With a variety of tailgate op- tions on the market, it's important to find the design that complements the specific quarry or mining operation. A tailgate enhances operations whether you're hauling aggregates, coal, iron, fly ash, oil sands, or soupy, viscous materials. But there are a couple of design aspects to consider before making a pur- chase decision, such as durability and versatility. First and foremost, work with a manufacturer that makes a EQUIPMENT MANAGEMENT Tailgates with durable components, such as steel alloy chains, last longer and perform better. Make sure the tailgate can lift high enough to avoid damage and carryback.