Question

A CAT D&H (power-shift) dozer is used to push material that weights 87 pcf in the bank state. It is estimated that the material will swell 5% from a bank state. The material is in a loose stock pile and is to be moved an average distance of 250 ft on a 2% downhill grade. The operator is average. Job efficiency is estimated to be at a 50-min hour. Assume that the dozer will have an 0.39 coefficient of traction. The O&O cost for the dozer is $86 per hour and the operator's wage is $17.50 per hour plus 44% for fringes, insurance and worker's compensation. Calculate the production in bcy per hour. (Reference Table 7.2 and Figure 7.13)

TABLE 7.2 Caterpillar job condition correction factors for estimating dozer production
Track-type tractor Wheel-type tractor
Operator
Excellent 1.00 1.00
Average 0.75 0.60
Poor 0.60 0.50
Material
Loose stockpile 1.20 1.20
Hard to cut; frozen
with tilt cylinder 0.80 0.75
without tilt cylinder 0.70 —
cable-controlled blade 0.60 —
Hard to drift; “dead” (dry, noncohesive 0.80 0.80
material) or very sticky material
Rock, ripped or blasted 0.60–0.80 —
Slot dozing 1.20 1.20
Side-by-side dozing 1.15–1.25 1.15–1.25
Visibility
Dust, rain, snow, fog, or darkness 0.80 0.70
Job efficiency
50 min/hr 0.83 0.83
40 min/hr 0.67 0.67
Direct-drive transmission
(0.1-min fixed time) 0.80 —
Bulldozer*
Adjust based on SAE capacity relative
to the base blade used in the estimated
dozing production graphs
Grades—see the graph

Answer 1