Drilling, hollow-stem auger

Hydrologists Jordan Drilling method Hollow stem auger, CME 75... 

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. 

In April 1982, before crops were planted, the drill rig was used to collect water samples from spots directly beneath the growing area of Field 5. A 30-cm metal well point with stainless-steel screen welded to the end of a section of hollow-stem auger was drilled to various depths below treated areas. Water samples were withdrawn through Teflon tubing inserted down the hollow stem into the point using the peristaltic pump. Sediment-free samples were bottled and stored for analysis as previously described. 

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