A limestone formation, with an average depth of $5$ ft is exposed over the full $80-$ft width and $23,700-$ft length of a highway cut. Preliminary seismic investigations indicate that the rock layer has a seismic velocity of $5,500$ fps$.$ The contractor proposes to loosen this rock by using a single$-$shank ripper on a power shift, track$-$type tractor.

The job conditions relative to lamination and other rock characteristics are average, or midway between adverse and ideal. A $40-$min hour working efficiency is possible. The contractor wishes to explore the use of two D$10$T$2$ Caterpillar dozers with single shank$($for performance data see the CAT Handbook posted on Blackboard and check the assumptions$).$

O&O cost for these tractors is $$126\mathrm{.}00$ per hour including rippers. However, dozers in ripping applications increase O&O cost $30-40\%.$ The operator's wage & benefits is $$74\mathrm{.}30$ per hour.

$1.$ What is the project duration with two dozers $(8$ hour work days$)?$ Round answer to nearest WHOLE days.

$2.$ What is the cost$/$bcy to rip this rock?