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Well Installation Procedures <br /> Permits obtained for monitoring well installation borings will be permitted through the San Joaquin County <br /> Public Health Services, Environmental Health Division. A truck-mounted drill rig equipped with 8-inch <br /> diameter hollow stem augers will be used to complete the borings. All equipment will be steam-cleaned <br /> prior to drilling. Sampling equipment will be cleaned with a laboratory grade detergent and rinsed with <br /> distilled water between samples to minimize cross-contamination. <br /> Soil samples will be collected continuously using either a 2-inch I.D. Modified California sampler, a <br /> continuous core sample, or a standard penetration split-spoon sampler. Soils encountered during drilling <br /> will be classified by Harza staff by visual examination in the field in accordance with the Unified Soil <br /> Classification System. Samples will be screened in the field using a portable photoionization detector. <br /> Field vapor measurements will be recorded on the boring logs. <br /> Borings completed as ground water monitoring wells will extend approximately 10 to 15 feet past the first <br /> encountered ground water. They will be terminated at a shallower depth if a minimum of 5-feet of clay, <br /> acting as an aquitard, is encountered. Soil cuttings produced by the drilling operation will be placed in 55- <br /> gallon drums and contained on site. Harza will assist Lincoln Properties, Ltd. with disposal of soil and <br /> water generated during drilling and well development activities. <br /> The borings will be converted to monitoring wells, using 2" Schedule 40 threaded PVC pipe and slotted <br /> screen. The perforations will extend approximately 10 to 15-feet below, and 5-feet above, the upper zone <br /> of saturation. The perforated section annulus will be packed with clean graded sand to a level <br /> approximately 2-feet above the highest screen slots, and a 1 to 2-foot thick bentonite plug will be placed <br /> above the sand pack. The remaining annulus will be backfilled with cement grout to grade. <br /> The wells will be completed at grade with a traffic rated concrete or metal box with a locking cap to guard <br /> against vandalism. No solvents or glues will be used during monitoring well construction. <br /> L198-G projmtltr\29312 <br /> 07-12-95 <br /> W A <br />