Section $1$: Drilling rock and earth

$$ A project utilizing experienced drillers will require drilling and blasting

of high$-$silica, fine$-$grained sandstone$($sedimentary rock$).$ From field drilling tests, it was determined that a penetration rate of $85$ ft$/$hr can be achieved with an HD bit $(31/2$ in$.)$ on a rotary percussion drill operating at $100$ psi. The drills to be used take $22-$ft steel. The blasting pattern will be a $12-\backslash$times $12-$ft grid with $3$ ft of sub$-$drilling required. On average, the specified finish grade is $16$ ft below the existing ground surface. Assume changing the steel needs $2\mathrm{.}5$ min.

$$ Determine the drilling production by filling in the table below.