Robert Neville wrote:

"Pete C." wrote:

Are you comparing the labor intensive old style deep hole or large
trench array, or the newer much better and much less labor intensive
trenched vertical coil installation?

Considering there is about 12" of dirt before you hit miles of granite and
fractured limestone where I live, his point is still valid...

You could modify the technique a bit for your area, by digging a 6' wide
trench to the ledge, laying the coil in horizontal and then back filling
and covering with another foot or two of dirt. Slight grade change, but
still no drilling or blasting.