CHAPTER 6CRUSHER SUPERVISOREquipment is provided by the Naval ConstructionForce (NCF) to enable the Seabees to meet aggregateproduction requirements. Of this equipment, crushingequipment is the critical item that provides thecapability to reduce and process material from a pit orquarry to produce finished aggregate in sufficientquality and quantityto meet constructionrequirements.Seabees are tasked with crusher operations in bothPacific and Atlantic fleet deployment sites. The NavalConstruction Training Center (NCTC), Port Hueneme,California, provides training for crusher operations;however, the majority of training in this area is achievedthrough on-the-job-training (OJT).The COMSECOND/COMTHlRDNCB direct thetasking of crusher operations conducted by the NavalMobile Construction Battalions (NMCBs). TheNMCBs schedule a predetermined number of man-daysfor crushing a variety of sizes and volumes of materialused to support construction projects, concrete plants,crete mobiles, and asphalt plants. At the end of adeployment, each battalion involved is usually taskedto turn over a specified number of cubic yards ofmaterial of various sizes to the relieving battalion. Themagnitude of the rock crusher tasking dictates the sizeof the crew assigned to support the rock crusheroperations.CRUSHER SUPERVISORRESPONSIBILITIESIn the Naval Construction Force (NCF), crusheroperations are usually managed by Alfa company. TheAlfa company operations chief is responsible forcrusher operations and should assign a crushersupervisor to direct the operations of the crusher. Thischapter presents important information an EO mustmaster to gain the basic knowledge of rock crusheroperations required to perform the duties of a crushersupervisor.ROCK CRUSHERCrushing plantsoutput. The mostare classified by their capacityoften used plant, classifiedmedium-to-large, has a rated capacity of 75 tonsper hour (tph). This plant has two separate anddistinct sets of equipment: the primary unit andsecondary unit.The primary unit reduces the quarry rock or coarsegravel by crushing. The secondary unit is primarily usedto process the crushed product.The amount of crushing required to produce asuitable amount of aggregate material depends upon theavailability of raw materials and the specificationsestablished for the end product. In any crusheroperations, there are four basic functions thathave to be accomplished. The four functions are asfollows:1. Particle size reduction by crushing.2. Separation into particle size ranges byscreening.3. Elimination of undesirable materials bywushing.4. Movement of the material from one location toanother.Primary UnitThe primary unit (fig. 6-1) consists of a20-inch by 36-inch standard type of jaw crusher(fig. 6-2), a vibrating grizzly, an under crusherdelivery conveyor, and a running gear. The jawcrusher can be powered by a diesel engine or byelectrical power. All other components are driven byindividual electricmotors.Normally, power issupplied by a 200-kW diesel generator. The runninggear is equipped witha fifth wheel and towingdolly.CAUTIONMake certain each electrically poweredcomponent is grounded.6-1
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