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SUBSURFACE EXPLORATION PROCEDURES <br />Hand —Auger Drilling (HA,) <br />In this procedure, a sampling device is driven into the soil by repeated <br />blows of a sledgehammer. When the sampler is driven to the desired sample <br />depth, the soil sample is retrieved. The hole is then advanced by manually <br />turning the hand auger until the next sampling depth increment is reached. <br />The hand auger drilling between sampling intervals also helps to clean and <br />enlarge the borehole in preparation for obtaining the next sample. <br />Power Auger Drilling (PA) <br />In this type of drilling, continuous flight augers are used to advance the <br />boreholes. They are turned and hydraulically advanced by a truck or <br />track —mounted unit as site accessibility dictates. <br />casing and drilling mud are not required to maintain lopenn auger boreholesdrilli.lg� <br />Hollow Stem Auger Drilling` (HS) <br />In this drilling procedure, continuous flight augers having <br />open <br />are used to advance the boreholes. The open stem allows theasamplingtem tools <br />to be used without removing the augers from the borehole. Hollow stem <br />augers thus provide support to the sides of the borehole during the <br />sampling operations. <br />Rotary Drilling (RB) <br />In employing rotary drilling methods, various cutting bits are used to <br />advance the boreholes. In this process, surface casing and/or drillin <br />fluid is used to maintain open boreholes. g <br />Diamond Core Drilling (DB) <br />Diamond core drilling is used to sample cemented formations. In this <br />procedure, a double tube (triple tube) core barrel with a diamond bit cuts <br />an annular space around a cylindrical prism of the material sampled. The <br />sample is retrieved by a catcher just above the bit. Samples recovered b <br />this procedure are placed in sturdy containers in sequential order. y <br />STS Consultants, Ltd.- <br />