ARCHIVED REPORTS XR0008677 - Laserfiche WebLink

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EC ® !R ATTACHMENT A FIELD AND LABORATORY PROCEDURES Exploratory Drilling The soil borings will be drilled using mud rotary equipment or sonic to a depth of approximately 180 feet bgs. The borings will be logged from 120 to 180 feet bgs by a SECOR International Incorporated scientist under the direction of a registered geologist using the Unified Soil Classification System and standard geologic techniques. Soil samples will be collected every 10 feet at depth from 120 to 180 feet from continuous soil cores. Soil samples for chemical analysis will be retained in brass liners, capped with Teflon squares and plastic end caps, and sealed in clean zip-lock bags. The samples will be placed on ice for transport to the laboratory accompanied by chain-of-custody documentation. Down-hole drilling and sampling equipment will be steam-cleaned following the completion of the soil boring. Down-hole sampling equipment will be washed in a tri- sodium phosphate or alconox solution between samples. Well Installation and Development The soil borings will be converted to groundwater monitoring wells by installing 4-inch diameter, flush-threaded, Schedule 80 PVC casing with 0.020-inch factory-slotted screen. Heavy wall casing will be utilized as conductor casing and will be advanced following the drill bit to the total depth explored in each boring in order to seal the upper groundwater bearing zones from the lower groundwater bearing zones. Approximately 10 feet of screen will be placed in the bottoms of the boring. A grade of sand appropriate to the screen size will be placed in the annular space across the entire screened interval, and will extend approximately 2 feet above the top of the screen for the wells. A bentonite seal will extend ; two to four feet above the sand pack. The monitoring wells will be completed with neat cement from the bentonite seal to the ground surface. The well casing will be topped with a locking cap. The wellhead will be contained in a watertight traffic-rated well box. The boring logs will show well construction details. fiK The well will be developed after completion. The development procedure for each well will consist of surging the well, then pumping or bailing water from the well until the water is "* visiblyclear, the well goes d or until a maximum of ten casing volumes have been g dry, g removed. The newly installed wells will be surveyed by a California State Licensed Surveyor. The well casings will be surveyed to the nearest 0.01 feet in elevation to a known benchmark. k ; r organic Vapor Proceduresf� Soil samples collected at 10-foot depth intervals during drilling will be analyzed in the field for ionizable organic compounds using a photo-ionization detector (PID) with a 10.2 eV lamp or a flame ionization detector (FID). The test procedure will involve measuring approximately 30 grams from an undisturbed soil sample, placing this subsample in a ;r y sealed container (either a zip-lock bag or a mason jar). The container will be warmed for lr"