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• <br />�71 <br />BORING <br />ASSOCIATED <br />ENDEDTURPOSE <br />SCREENq <br />DEPTH't <br />WELL <br />INTERVAL <br />;TOTAL <br />B6 <br />MW -7B <br />B -Zone Momtonng Well <br />77-81 <br />81 <br />B8 <br />MW -9B <br />B -Zone Momtonng Well <br />78-83 <br />83 <br />B10 <br />MW -10C <br />C -Zone Momtonng Well <br />107-112 <br />112 <br />B9 <br />MW -17B <br />B -Zane Momtonng Well <br />76 5-79 5 <br />79.5 <br />B11 <br />MW -18B <br />B -Zone Monitoring Well <br />80-85 <br />85 <br />B5 <br />MW -19C <br />C -Zone Monitoring Well <br />105-110 <br />110 <br />B4 <br />MW -20A <br />A -Zone Monitoring Well <br />51-66 <br />66 <br />B4 <br />MW -20B <br />B -Zone Monitonng Well <br />77-82 <br />82 <br />MW -8S <br />MW -8S <br />Sentry Well <br />205-210 <br />210 <br />EX -3 <br />EX -3 <br />Groundwater Extraction Well <br />60-80 <br />80 <br />An RMC 2/12 sand pack, or equivalent, was placed in the annular space across the entire <br />screened interval, and extends approximately 1 to 2 feet above the top of the screen for the well <br />A bentonite and Portland cement seal was extended from the sand pack to the ground surface <br />The bonng logs show well construction details and can be found in Attachment E <br />The wells were developed and sampled after completion The development procedure for each <br />well consisted of pumping or baiting water from the well until the water was visibly clear, the <br />well went dry, or until a maximum of ten casing volumes had been removed After <br />development, water levels were allowed to partially recover Groundwater samples were then <br />collected using a disposable teflon bailer, placed into appropnate EPA -approved containers, <br />labeled, placed on ice, and transported to the laboratory accompanied by chain -of -custody <br />documentation <br />The newly installed wells were surveyed by a California State Licensed Surveyor The well <br />casings were surveyed to the nearest 0 01 feet in elevation to a known benchmark. <br />Organic Vapor Procedures <br />Soil samples collected dunng drilling were analyzed in the field for ionizable organic compounds <br />using a flame -ionization detector (FID) or a photo -ionization detector (PID) with a 10 2 eV lamp <br />The test procedure involved measuring approximately 30 grams from an undisturbed soil sample <br />and, placing this subsample in a ziplock type bag The container was warmed for approximately <br />20 minutes (in the sun), then the head -space within the container was tested for total organic <br />vapor, measured in parts per million as benzene (ppm, volume/volume) The instrument was <br />calibrated pnor to dnlling using a 100 -ppm isobutylene standard (in air) and a sensitivity factor <br />