Aggregates Manager Digital Magazine
Issue link: http://read.dmtmag.com/i/815541
AGGREGATES MANAGER Voices of Experience Chris Connolly Eric Yeomans Erin Waldron U sing equipment at the quarry face may be the most challeng- ing place (and is certainly in the top three) for a machine operator to work in an aggregates operation, says Chris Connolly, product manager for GPE products, Volvo Construction Equipment. Overall smooth operation is important, but so are all the details that come with it. "First and foremost, you need to mon- itor how much power you are applying to the machine," he says. "Be aware of its power and be extremely confident in operating it. Make movements deliber- ate and smooth." Choppy, erratic actions are not only inefficient, but can result in second- ary issues. For example, applying too much power can cause the equipment's tires to slip. This, in turn, causes wear and tear on very expensive (upwards of $20,000 for Volvo's largest wheel loader) tires. "And, as soon as the tires start slipping, you won't be able to get the maximum amount of material in the bucket," Connolly explains, adding the underfoot will also be affected and should be graded out. Maintaining the grade and keeping the underfoot condition in good shape is essential because it helps to protect proper drainage. "You need to keep the grade so water is not held in the loadout area," Connolly says. "This is very important. If you're not taking care of it and have big ruts, it is just slowing the operator down, because he can't operate at maximum efficiency." A loader operator also needs to ensure he won't create any problems at the crusher. "As loading blasted rock into the truck going to the crusher, be aware of the largest rock the crusher can handle," Connolly advises. "If you pick up a larger rock, put it to the side and let the excavator operator with a rock breaker take care of it." B efore approaching a muckpile, a loader operator needs to be aware of its characteristics, including what it looks like, how tall it is, and its density to determine the right bucket for the machine is being used. "You don't want a machine going into a muckpile that towers over the ma- chine," Yeomans says. "There is concern of material rolling, hitting the machine, and getting in the way. If the pile ex- ceeds its height, send in a different type of machine, such as an excavator, to move material around to make it more suitable for the loader — to take off the high points that are at risk of rolling or avalanching." Blasting techniques also play a role in whether the muckpile will tower over the top of the machine. "Sometimes, there are soft veins of rock, and they get more blasted out than originally planned," Yeomans says. "Generally, in a blasting plan, the height of the face is measured, and the amount of explosives is gauged accordingly, but there can be anomalies, fissures and cracks, and other things that can cause a higher muckpile." When a loader operator begins to work on the muckpile, consistency is imperative. "The machine operator should systematically take buckets [of material] from left to right, working back toward the face," Yeomans says. "There needs to be uniform removal of the material — not just one spot at a time." It is also extremely important to use the correct bucket attachment. The bucket size is determined by the model and size of the machine, as well as weight and density of the material, Yeomans says. "You try to match your bucket to the material and size of truck being loaded," he says. "You want to load it to the maximum payload potential." A t Cemex's Brooksville Quarry in Brooksville, Fla., the training is the same for all excavator operators. It is conducted with a series of steps to ensure proper and efficient training for an excavator operator. "Excavator operators in training are observed by a qualified operator as part of the training process," says Erin Wal- dron, aggregates supervisor for Brooks- ville Quarry. "They are required to read and understand the operation manual. Trainees are then observed completing a series of increasingly demanding tasks." The training covers not only operating the excavator itself, but also the proper way to approach a muckpile, deal with mud seams and the toe, and procedures dealing with loading at the quarry face. "We train operators to approach muck- piles at the same level at the bottom of the piles," he explains. "They start pulling materials, and as it is moved out, it creates a natural ramp for the excava- tors. The process is repeated until they reach a proper access height to create a bench." The operators pull material from the highest points and fill in low areas to create level benches from which to load. The bench height is determined by the stick length of the excavator, which will be used when loading haul trucks. "The operators then load the trucks on the floor from the bench," Waldron says. Dealing with mud seams, however, is not as cut and dry. It requires knowledge about the aggregate itself. "It is deposit specific," Waldron points out. "We use excavators to load from the muckpile so that we can be very selective along the face and move aside or strip out what we can't use." Dealing with the toe is determined by the drilling pattern and shot design. "Proper time and effort to ensure your blasting is done properly will minimize the problems with hard toe," he says.