Auger Drilling

For normal hole advancement, a pilot bit is inserted through the cutter head to drill the center of the hole. The drill rod is bolted to the inside of the drive cap with a rod-to-cap adapter so that the pilot bit can turn in tandem with the augers. This method allows for split spoon sampling, Shelby tube sampling, Dennison sampling, Hydro punch discrete water sampling, and rock coring to be performed while leaving the augers in place.

Drill rods are normally added each time an auger is added. In soft formations (dirt and sand), a tapered wooden plug may be inserted into the end of the cutter head to prevent material from going up inside the augers and eliminates the use of drill rod. When the hole is completed, the plug may be knocked out the bottom of the auger string. The next step is to insert the monitoring screen and casing, which is then grouted into place to prevent contamination from the top of the hole.