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L <br />3.3.2 Drilling, Soil Sampling, and Logging Methods <br />Prior to beginning drilling operations and between each location, all drill rig and sampling <br />equipment will be properly decontaminated using high-pressure wash and steam -cleaning <br />equipment. Monitoring well boreholes will be drilled using an 8 -inch diameter hollow stem <br />auger. In the unsaturated zone, samples will be collected at five-foot intervals using a <br />California -modified split -spoon sampler. At a minimum, geologic logging of boreholes will <br />address the following elements: <br />■ Borehole designation and location. <br />■ Times and dates that drilling/excavation began and ended. <br />■ Type of exploratory equipment being utilized, including manufacturer, make, and <br />model for special modifications. <br />■ Name(s) and registration numbers for geologist(s) responsible for log description. <br />■ Name(s) of other personnel assisting in the logging. <br />■ Weather conditions. <br />■ Description of soils according to the Unified Soil Classification System and <br />description of bedrock materials according to accepted geologic nomenclature. <br />■ Systematic descriptions of lithologic and micro -structural changes in strata or soil <br />horizons, including thickness of units as well as the depth and elevation of lithologic <br />changes. <br />■ Presence of and depth to groundwater. <br />■ Caving or sloughing conditions in the hole, including depth and elevation. <br />■ Sampling interval(s), including depths and elevations. <br />■ Unusual color, staining, or odors of chemical or waste origin. <br />■ Drilling advancement in feet -per -hour (average) and/or feet -per -minute, noting <br />periods of difficult or very easy drilling. <br />■ Any subsurface structures or unusual features encountered. <br />■ Descriptions of mineral seams and fracture fillings. <br />■ Faults, gouge, or shear zones penetrated. <br />■ Depth and thickness of weathering. <br />■ An opinion as to the characteristics and hydraulic conductivity of water -bearing <br />lithologies. <br />■ Other notes and descriptions as required. <br />Drill cuttings will be spread on the ground at each drilling site. <br />3.3.3 Temporary Well Construction and Initial Groundwater Sampling <br />Once groundwater is encountered, the borehole will be advanced about S feet deeper, and <br />then the augers will be withdrawn in preparation for temporary well installation. The <br />temporary will will be constructed using one -inch diameter, Schedule 40 PVC casing and <br />screen. The screen will have 0.020 -inch slots. The screened interval will be backfilled with a <br />2011-0115 CHSL EMP Workplan <br />Revision 2 — January 11, 2012 <br />0 <br />Geo -logic Associates <br />