Aggregates Manager Digital Magazine
Issue link: https://read.dmtmag.com/i/107584
operator, or management. These tasks are accomplished daily by the dredge operator or deckhand without taking apart any components and do not directly involve management; however, it is important that a written record of these tasks is provided to management. The phrase "cleanliness is next to godliness" cannot be more applicable when dealing with the Mine Safety and Health Administration (MSHA) regarding a dredge. Often, MSHA inspectors do not want to be on the water in the first place, and the last thing they want is to encounter a machine in disrepair, coated with oil and grease, and laced with debris; the dredge should be cleaned at least at every shift change to promote an atmosphere of pride and respect. Since a dredge is a floating machine, the trim and heel (stability front to back and side to side, respectively) of the vessel should be visually checked upon boarding, departure, and routinely throughout the day. Any noticed change in either draft or lean should be immediately inspected, corrected, and reported to management. Most flotation problems are a result of manholes that are not tightened properly or from corrosion, stress, and rubbing problems that cause a crack or hole in a tank. These issues can be quickly remedied with pumps, epoxy, wooden dowels, or concrete, and can be permanently fixed during regularly scheduled maintenance periods. It should be noted that dredge flotation tanks are often considered confined spaces, and company procedures for entering these tanks must be strictly followed. On a daily or shift basis, swing, spud, and lift cables should be inspected for fraying, wear, and proper fleet. Lift cables should be replaced immediately, as a failure on a ladder or bucket lift system can be financially, as well as humanly, catastrophic. Frayed swing or spud cables usually only result in downtime and should be replaced at the first scheduled maintenance time. 16 AGGREGATES MANAGER February 2013 Sheaves, bushings, and bearings — especially those that are submerged — should be lubricated every shift to prevent wear. Lubrication and inspections usually require less than 30 minutes per dredge shift; the installation of automatic greasing systems can greatly decrease lubrication time, as well as ensure that every grease point is properly lubricated. Pressurized hydraulic oil lines and water hoses should be visually checked for leaks and frays anytime the equipment is above the surface and operating. Most modern dredges provide operator alarms for leaking hydraulic systems. A leaky hydraulic system tors that a hazardous condition or problem exists. These situations should be corrected promptly; the manufacturer or the maintenance personnel should eliminate nuisance or faulty alarms if they occur. 2. Routine sampling and analysis Routine sampling and analysis provides insight into the health of the dredge and its likelihood to need major repairs in the near future. These major tasks often require more skilled maintenance personnel and additional scheduled service time. The OEM often Visual inspection and lubrication of dredges is critical for safety, environmental, and immediate operation concerns. will, without fail, end in an injury or an environmental fine. All equipment oil levels should be checked daily or at the OEM's recommended intervals. All electrical equipment should be visually inspected for rubbing or loose external connections. Structurally loaded components should be visually checked for cracks, and abrasively attacked surfaces should be checked for wear. Clamshell bucket shells and lips, dragline booms and buckets, cutter heads and drives, dredge ladders, and spuds are good examples of these components. Additionally, all equipment guards should be inspected for proper bolting and fit. Lastly, dredge manufactures should provide sufficient alarms to warn opera- provides maintenance and testing schedules, but common sense can be used to create a schedule if none is provided. Diesel engine oil should be sampled and analyzed in a lab at least every 500 hours and hydraulic oil at least every 1,000 hours. The presence of water in the oil during the normal inspection should trigger more frequent testing or immediate corrective action. The analytical results from the testing lab should indicate any required testing schedule change or upcoming corrective equipment repair. Baseline temperatures of all equipment, including electrical switchgear, motors, and connections, should be taken upon commissioning with an infrared heat gun. Monthly comparative readings should be observed; a high temperature is often an indication of a