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<br />TASK 2 <br />BACKFILL AND GRADE PIT AREAS <br />Material Volume and Area <br />Assume maximum of two open pits at 26,000 cy (in-place) each for a total of 52,000 cy <br />(in-place) or 58,200 cy (loose assuming 12% swell). Associated surface area would be <br />approximately 3 acres. <br />Equipment and Productivity <br />Use a CAT 627E Tractor Scraper for backfilling <br />Haul Distance -Approximately 1,000' average one-way at a flat grade (0%) and a rolling <br />resistance of 5% <br />Cycle Times -One-way haul time would be 0.65 min. (loaded) and 0.5 min. (empty). <br />Fixed cycle times (load, dump, and spread) would be approximately 1.0 min. Total cycle <br />time would be approximately 2.15 min. <br />Average Capacity -Approximately 14 cy (loose) <br />Productivity -Approximately 27.9 cycles/hr. or 390 cy (loose)/hr. Using an operating <br />• factor of 0.83 (50 min. operation/scheduled hr.) results in an adjusted productivity of 324 <br />cy (loose)/hr. <br />Use CAT D9R DS Tracked Dozer for grading <br />Productivity -Average grading distance is 300' and blade width is 14' 9". Dozer grades <br />(forward) at 4 mph in 2ntl gear and returns (reverse) at 5 mph in 2"tl gear. <br />((300 ft. x 14.75 ft.) x 1 acre/43,560 ft.Z)/(300 ft x 1 hr./4 mi. x 1 mi./5280 ft) + (300 <br />ft x 1 hr./5 mi. x 1 mi./5280 ft) + (0.05 min. fixed time x 1 hr./60 min.) = 3.85 <br />acres/hr. <br />Using an operator factor of 0.75 (average) and an operating factor of 0.83 (50 min. <br />operation/scheduled hr.) results in an adjusted productivity of 2.4 acres/hr. <br />Equipment Hours and Cost <br />Backfilling would require 180 scraper hours to complete (22 days at 8 hrs. per day). <br />Grading would require approximately 2 hrs. <br />180 hours x ($136.35/hr. (627F Scraper)) _ $24,543 <br />2 hrs. x ($150.96/hr. (D9R Dozer)) _ $302 <br />• <br />L~ Revised May 1998 <br />