Business Finance – Operations Management
600 lf @ 4% grade
1000 lf @ 0% grade
400 lf @ 6% grade
631 E Scraper $115/hr
D9 Dozer $165/hr
step1. Weight
Empty Vehicle Weight 96880 lbc
Load Volume
Scraper Capacity 31 lcy
Adj. Cap Load Time 26.7 lcy
Push Load Factor 29.3 lcy
Convert to BCY
Swell Percentage 35 %
Adj. Volume Cap 21.7 bcy
Material Weight
Unit Weight 3000 lbs/cy
Payload 65169 lbs
Gross 162049 lbs
step2.Rolling Resistance
RR 4 %
RR (lbs/tn) 80 lbs/tn
step3-6. Grade Resistance,Total Resistance,Travel Speed,Travel Time
Haul Section Dist (ft) RR (%) GR (%) TR (%) Speed (mph) Time
Accel 300 4 3 7 6 0.57
400 4 3 7 11 0.41
800 4 2 6 14 0.65
1600 4 0 4 20 0.91
Deccel 300 4 0 4 6 0.57
Return Section Dist (ft) RR (%) GR (%) TR (%) Speed (mph) Time
Accel 300 4 0 4 6 0.57
1600 4 0 4 32 0.57
800 4 -2 2 33 0.28
400 4 -3 1 33 0.14
Deccel 300 4 -3 1 6 0.57
Travel time: 5.32
step7. Load time
Load time 0.85 min
step8.Dump time
Dump time 0.37 min
Scraper Production Estimating Using the Scraper Production Estimating Format outlined in your textbook and the scraper specifications in Table 8.1 and on
the performance charts in Figures 8.10 and 8.11, analyze the probable scraper production. The material to be hauled is a sandy
clay (dry earth), 2,850 lb/bcy. The expected rolling resistance for the haul route is 80 lb/ton. Use a load time of 0.80 minutes,
which will result in an average haul load of 90% heaped capacity. To account for both acceleration and decelaration, use an
average speed of 6 mph over a distance of 200 ft. Use a 55-min hour efficiency factor. The total length of haul is 2,000 ft and
has the following individual segments when moving from cut to fill:
Total Ownership and Operating Costs (including operator)
conditions?
Sheet1 step9. Turn Times
Cut 0.3 min
Fill 0.21 min
step10. Total cycle time
Total time 6.96 min
step11. Pusher cycle time
(1.4xLt) -> 0.25 1.44 min
step12. Balance Fleet
Scraper cycle time 6.96 min
Dozer cycle time 1.44 min Balance Fleet= 4.8
step13. Effeciency Factor
0.92
step14. Production
Scraper Controled production 4 scrapers
Cycles 7.19 cycles
Production
step15. Cost
631 E Scraper $130/hr
D9 Dozer $225/hr
Scraper controled production 4 scrapers
Scraper cost $520/hr
Dozer cost $225/hr
Total crew cost $745/hr
Dozer controled production 5 scrapers
Scraper cost $650/hr
Dozer cost $225/hr
Total crew cost $875/hr
