Hollow-stem auger materials

Drilling. Common drill rigs available for monitor-well installation include cable tool, air rotary, mud rotary, reverse rotary, and hollow-stem auger. The cable tool rig repeatedly lifts and drops a drill bit, drill stem, drilling jars, and rope socket. The drill bit crushes hard rock or loosens unconsolidated material and mixes the loosened particles with water to form a slurry or sludge. The sludge is removed at intervals by a sand pump or a bailer. 

The hollow-stem auger is mobile and inexpensive to operate. It is capable of drilling approximately 150 feet into unconsolidated material. (Practical experience indicates that 100 feet may be successfully drilled.) The rig is equipped with a removable plug that helps in the drilling process, but that is inserted inside the hollow stem of the auger and is, therefore, easily removable. 

Surface and subsurface soil and aquifer matrix material (to an 8-m depth) were collected in an aseptic manner in presterilized 6.35 cm (width) PVC tubes using a hollow-stem auger from six sites over die Big Sioux Aquifer near Aurora, SD (19). The water table at the time was 7 m below the soil surface. 

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