Aggregates Manager

November 2013

Aggregates Manager Digital Magazine

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PLANT PROFILE Because the mountain is so steep and benches so narrow, Ogano Quarry discontinued the use of wheel loaders and now uses excavators to load haul trucks in the quarry. wash plant. The wash plant is used for those customers who prefer clean, washed stone; plus it helps control dust. Material is usually run through the crushers three times. If a round-shaped rock is desired, the material is crushed a fourth time. The smallest rock produced at the quarry is 2.5 millimeters. "We usually make rocks a maximum of 40 millimeters in size," Kurihara says. "We only make 80 or 85 millimeter rocks on request. The largest stone we make is a garden stone, usually 35 centimeters in size. We separate those stones depending on customer demand." When it comes to loadout, the quarry has no truck fleet of its own, so everything is loaded onto customer trucks. Silos are used for loading dry rock into customer highway trucks at the dry plant, and wheel loaders load the trucks at the wash plant. In keeping with the smaller size of most vehicles found in Japan when compared to their U.S. counterparts, customer highway aggregate trucks only hold 10 to 12 metric tons of material. However, a larger truck would have difficulty maneuvering on the 12 tree-lined mountain roads leading into the quarry. The roads are beautiful, but narrow and winding, with occasional turnouts to allow customer trucks going in opposite directions to pass each other. Ogano Quarry loads an average of 300 customer highway trucks per day. It processed and shipped 800,000 tons of stone last year, but is capable of producing 1 million tons annually. Approximately half of the stone produced is being used for concrete and water-permeable concrete for the walls of tunnels being built under Tokyo. Another 35 to 40 percent of the stone is used for road base. The rest is used for railroad ballast. The quarry is expected to last another 15 to 20 years, at which time quarrying will move to the mountain on the other side of the valley and processing plant. "Only one side of the mountain is mined," Kurihara says, "then it is replanted with cedar trees to bring the green back to the mountain." The trees are expected to help with erosion control and prevent landslides, as well as return the mountain to a natural state. AM To see the operation in action, visit Equipment List Furikawa drill Caterpillar 385C hydraulic excavators (2) Caterpillar 771D haul truck (2) Caterpillar 769D haul truck Caterpillar 772D haul truck Caterpillar 988H wheel loader Caterpillar 966H wheel loader (3) Caterpillar 980H wheel loader Caterpillar D6 dozer Caterpillar D8 dozer 48-inch jaw crusher Cone crusher AGGREGATES MANAGER November 2013 PlantProfile_AGRM1113.indd 12 10/17/13 2:05 PM

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