If the main costs were permits, equipment rentals and crew, then your math is way off. By definition, those are mostly fixed costs so the first foot is phenomen

If the main costs were permits, equipment rentals and crew, then your math is way off. By definition, those are mostly fixed costs so the first foot is phenomenally expensive. A crew can easily dig 1/2-1 mile per day, so maybe 4 days instead of the one to dig a few feet. If 1/2 the cost was equipment and crew and the other half permits, that puts us at a $5k total.