The drilling process is quite interesting and it is a lot like the process of drilling for oil only on a much smaller scale. The drill pipe is hollow and threaded. At the end of the first pipe (shown in closeup)is a drill bit that has holes in it to allow the water to circulate down and out of the hole to float out the drilling tailings. Additional joints of pipe are added until the desired depth is achieved.

When the hole is deep enough, the drill bit and drill pipe are left in the hole and grout is forced down the pipe and left in place to set up. When the mud/grout has set up, the pipe will be imbeded deeply in the ground and it would take a tremendous force to dislodge it.