A contractor used a 3-cubic-yard hydraulic excavator to dig a hole for the foundation for an office building and stockpile the excavated material. The building foundation and the first floor have been constructed, and the contractor is planning to use a tracked dozer to backfill the foundation with material from the loose stockpile. The average haul distance (one way) for the dozer is estimated to be about 350 feet, and the backfill volume is estimated to be 900 compacted cubic yards. The site is fairly level. Soil tests on the backfill material indicate a swell percentage of 25% and a shrinkage percentage of 18% when compacted to the design density. The blade capacity is estimated to be 70 loose cubic feet. The operating weight of the dozer with a straight blade is 31,105 pounds. Assume a fixed time of 0.05 minutes and that the operator will push in first gear at a speed of 1.5 miles per hour and backup in second gear at a speed of 2 miles per hour. Operational efficiency is estimated at 50 minutes per hour. Ownership and operating costs are estimated to be $130, and the operator earns $60 per hour including fringe benefits.