Hollow stem augers attached to the rig can drill, sample soil borings and install monitoring wells. Hollow stem drilling is effective in unconsolidated soils, when holes are prone to collapsing, the casing allows the hole stay open which is essential for DCPT testing, SPT testing, and well installations.
Hollow Stem Auger Drilling is proven to be one of the oldest and most reliable forms of drilling. This technique provides sufficient evidence when identifying water-producing zones. The Hollow Stem Auger is a small, lightweight, maneuverable rig that is most commonly used for two purposes which include; setting groundwater monitoring wells for environmental and geotechnical applications or collecting water samples for testing through its hollow stem.
The Hollow Stem Auger Drill consists of a “hollow stem” with the claw bit attached to the end. The reason for the hollow stem is to act as a temporary casing, this keeps all sides of the bore hole from closing in. Hollow Stem Auger has two purposes; retrieving samples from the borehole or installing a groundwater monitoring well. A major advantage of the Hollow Stem Auger Drill is the well installation that is applied directly through the auger into non-cohesive material. A disadvantage is how the drill is unable to penetrate through cobbles, boulders and most rock formations.