A limestone formation with an average depth of 25 ft is exposed over the full 450-ft width and 15,000-ft length of a highway cut. The rock has a seismic velocity of 5,000 fps. The contractor proposes to loosen this rock with 3 D9R dozers each with a single shank ripper. The job conditions relative to lamination and other rock characteristics are average, or midway between adverse and ideal. A 45-min production hour is appropriate. 0&O costs for each D9R in this ripping application are $160/hr. The operator\'s wage is $25/hr. What is the estimated unit cost to rip this rock? What will be the total cost of the work, and how many hours will the project require?