Question

A contractor wants to explore using a 7U blade on a 240 hp dozer. The material is a
dry, noncohesive silty sand and must be moved a distance of 200 ft from the
beginning of the cut. It is estimated the material will swell 4%, from bank to loose
state. Both visibility and traction should be satisfactory. Job efficiency is assumed to be
equivalent to a 50-min hour. The U-blade width is 13 ft 1 in with 3.25 ft of wing
width, and a height of 5 ft 1.1 in. The wing angle is 28.0 deg. Assume an average push
speed of 3 mph and a return speed of 4 mph. Calculate the direct cost of the proposed
earthmoving operation in dollars per bcy. Assume that the O&O cost for the dozer is
$89.50 per hour and the operator’s wage is $19.00 per hour plus 30% for fringes and
worker’s compensation. ($0.225/bcy)

Answer 1