Pier drilling is a process which uses an augur to drill deep down into the ground, for the purpose of establishing piers or columns upon which a foundation can be placed to support a structure above ground. It is very often used in locations where the ground is not particularly stable, and where it would be unsafe over the long haul for building construction. Piers are often drilled down deep enough so they can rest in either stable ground, or on solid bedrock, which can provide a very solid base for supporting anything above.