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'IIIINW � <br /> GEOMATRIX <br /> �r <br /> A. The height of the drilling table above ground surface, lengths of the drill bit, <br /> sub and drill collars, and length of drill rods should be taken into account in <br /> calculating the depth of penetration. <br /> B. In mud rotary drilling, a small diameter, fine mesh, hand screen will be used to <br /> obtain a sample of the cuttings from the borings by holding the screen directly <br /> in the flow of the drill fluid return line. In air rotary drilling, cuttings will be <br /> collected after discharge from the cyclone. <br /> C. In rotary drilling, a composite sample may be obtained from the return line by <br /> leaving the screen in place during the time it takes the driller to advance the <br /> boring to any preselected depth. <br /> D. In rotary drilling, the travel time for cuttings to reach the surface may be <br /> estimated each time the driller adds a new length of drill rod by timing the first <br /> arrival of cuttings after circulation is resumed. This travel time will be used <br /> along with the depth of penetration to estimate the start and finish of each 5-foot <br /> sampling interval. <br /> 3.2 LOGGING OF EXPLORATORY BORINGS <br /> The observations of the field geologist/engineer will be recorded on a BORING LOG OR <br /> WELL LOG at the time of drilling. The drill rig operator and the field geologist/engineer <br /> will discuss significant changes in material penetrated by the drill, changes in drilling <br /> conditions, hydraulic pressure, drilling action, and drilling fluid circulation rate. The field <br /> geologist/engineer will be present during drilling of soil borings and will observe and <br /> record such changes by time and depth. <br /> r� <br /> Drill cuttings and core samples will be observed in the field. -A lithologic description will <br /> be recorded on the log using the Unified Soil Classification System (USCS) as described in <br /> ASTM D 2488-90. This description will include the USCS soil type, grain sizes and <br /> A <br /> estimated percentages of each, moisture content, color according to the Munsell color charts <br /> (Kollmorgen Instruments Corp.), plasticity for fine-grained materials, consistency or <br /> DRILLING AND DESTRUCTION OF SOIL BORINGS <br /> MSCIGEOMATRX.PRO REVISION DATE: NOVEMBER 1992 Page 4 of 6 <br />