A 240 hp (power-shift) dozer is used in a pushing operation. The dozer is equipped with a straight blade.
The material (dry and noncohesive) weighs 98 pcf in the bank state. 2,646 lb/bcy
It is estimated the material will swell 6%, from bank to loose state.
The center-of-mass–to–center-of-mass pushing distance is 200 ft.
Job efficiency can be assumed to be equivalent to a 45-min hour.
Calculate the production in bcy per hour and the direct cost of the proposed earthmoving operation in dollars per bcy.
The company’s normal O&O cost for these machines is $95 per hour and the operator’s wage is $15.00 per hour plus 40% for fringes, insurance, and worker’s compensation. (224 bcy/hr, $0.519/bcy).
An earthmoving contractor encounters a trap-rock at shallow depth in a cut.
Seismographic tests indicate a seismic velocity of 6,500fps for the material.
On this basis, it is proposed to rip the rock with a 370-hp crawler tractor.
Estimate the production in bcy, for full-time ripping, with 45-min hour
Assume that the ripper is equipped with a single shank and that ripping conditions are average (i.e., intermediate between extreme conditions).
The normal O&O cost per hour, including operator, for a tractor w/ ripper $95.82
This is classified as heavy ripping. Using your estimate of hourly production, estimate the ripping unit-production cost in dollars per bcy.
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