Aggregates Manager Digital Magazine
Issue link: http://read.dmtmag.com/i/878969
AGGREGATES MANAGER / September 2017 9 in, so we need to be able to move to where the work is," says Travis Mylroie, aggregates operations manager at Four Corners Materials' Animas Glacier Facility in Durango. "Also, it allows us to move different plants to different pits depend- ing on what needs to be produced. So, if we have a big job for asphalt and need to put up a lot of material for it, we'll put one of our larger plants there, but if we're just restocking a pit with road base, then a smaller plant with a lower operating cost works out better. The same goes for the wash plants, we have fi ve batch plants spread over our area, so it's more cost effective to produce the materials in a closer location to keep trucking costs down. Being portable allows us to be very versatile." "We've been here three and a half years now," says Kyle High, general manager at Four Corners Materials. "We put in the fi rst crusher at the end of 2013. Concrete and asphalt came in two years ago." When deciding where to move a crushing plant, they used a drone to take an aerial photograph of the area. It took a picture of the plant where it was sitting, took another picture of the area where they wanted the plant to go, measured everything out, mapped them together, and shot the points where the plant would sit in the pit. That way, when they moved the plant, the drivers could just drop it between the points. "We didn't have to be over here stepping it out and measuring it out to set it up," Mylroie says. "They just set it between our pegs, dropped it off, went to get more, came back, and put the belts in. The drone really helped out with the process." "We're fi nding more and more things for drones to do all the time," High explains. "We use them for measuring stockpiles, so we don't have guys climb- ing on these piles trying to measure them. And we use them for construction. We're mainly heavy highway — we like the paving — but also do dirt work and utilities." There is a well on site that supplies water for the wash plant and other operations, but it only generates 35 gallons of water per minute, so a clarifi er is needed. The operation just installed a new clarifi er 15 feet taller and 1 foot larger in diameter than the old one. The dirty water from the wash plant is pumped into the middle of the clarifi er where it mixes with a polymer fl occulant that makes the sediments drop to the bottom. The clean water is then recircu- lated back to the water tank that feeds the wash plant. Mylroie says the new clarifi er "makes mud thicker than chocolate pudding with almost no water in it at all." This is thanks, in part, to a new dry fl occulant system. A laser eye in the clarifi er de- termines how dirty the water is, and the automated fl occulant system adjusts the amount of fl occulant needed. Once the mud at the bottom of the clarifi er reaches 37 percent, a pump kicks on and sends it out through a 4-inch underground pipe and dumps it into one of two, lage rectangular settling ponds in an area above the pit. After the mud settles out and the water level gets high enough, the clean water will be returned to the water tank below. Operations The entire operation is run by a crew of 24, including Mylroie. The crusher and wash plants each run a three-man crew. The ready-mix batch plant requires 13 — a batch operator, a loader operator, a quality control technician, and 10 drivers. The hot-mix asphalt plant has a crew of three — a plant operator, a loader operator, and a ground man. Operating hours are from 5 a.m. to 6 p.m., but the hours can be extended if a night job requires hot-mix asphalt or an early morning paving job requires ready-mix concrete. There is no blasting at the operation, but scrapers are required to strip off approximately 10 feet of overburden and push it aside for use in future reclama- tion. Below the overburden is a layer of gravel approximately 80 feet deep. "We need a large volume of feed stock and should be able to get that easily," Mylroie says. "We bench down in the pit and strip off the deposit until we get to a layer of clay. That layer varies in thickness from a couple feet thick on one side to approximately 8 feet thick on the other. The material on top of the clay is a bit dirty, real rocky, but works great for base and such. We'll strip the clay off and make feed stock out of the material underneath. The material is really clean under that clay and makes the wash plant run a lot faster." A dozer works the pit from 60- to 70-foot benches, pushing the material Once the dozer pushes the material down, a loader picks it up and feeds it to the dry plant for crushing and sizing.