a 5-minute scraper cycle time divided by a l-minutepush cat cycle time calls for five scrapers per push cat.TurnsWhen making turns, turn within the shortest radiuspossible and at the highest safe speed When makingturns to perform cut and spread operations, use thesequence shown in figure 10-48.Haul RoadsHaul roads should be level and laid out so time isnot wasted in maneuvering the scraper. A haul road thathas drastic changes in elevation reduces production.Haul roads should be kept in good condition and moist.Roads kept moist, not wet, packs into a hard smoothsurface that permits higher travel speeds. The moisturealso controls dust that gets into all parts of the scraper,resulting in increased lubrication problems andpremature wear.Additionally, controlling the dustallows better visibility.If the haul road is a dirt road and needs grading,while returning to the cut, maintain the roadoccasionally with the scraper blade. This is performedby opening the apron approximately 12 inches above thecutting edges and the ejector positioned forward towithin 6 inches of the cutting edge. The bowl is lowereduntil the cutting edges scrape about 1 to 2 inches of theroad surface. By watching the road, the operator canvary the cutting action to trim small rises and carry thematerial to fill depressions, as the scraper travels thehaul road These grading operations can be performedin second or third gear, depending upon road conditions.Grading should only be done when the road surface hasruts and rough or soft spots.NOTE: Scrapers on the haul road should onlytravel in the highest gear that is safe for the roadScraper Spacing EfficientlyScrapers should be teamed by their speed wheneverpossible. The fastest scrapers should be assigned to onesection of a job, while the slower ones are on another.They should use different haul roads if possible.NOTE: No scraper can travel faster than thescraper ahead of it. Passing only increases the chancesof accidents.Scraper operators can help in traffic control byspeeding up to close along gap and slowing down whentoo close. Efficient spacing supports the optimum useof the push cat. When unloading and lagging far behindthe next scraper, spread the load at the beginning of aFigure 10-48.-Cut and spread sequence.10-26
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