ARCHIVED REPORTS XR0002747 - Laserfiche WebLink

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• ATTACHMENT C FIELD AND LABORATORY PROCEDURES I Exploratory Drilling The soil borings will be drilled using 8 or 10-inch hollow-stem auger drilling equipment (depending on diameter of well casing to be installed) to depths ranging from 40 to 77 feet bgs Borings will be logged by a SECOR International Incorporated scientist under the direction of a registered geologist using the Unified Soil Classification System and stan- dard geologic techniques Soil samples for logging will be collected continuously using a California-modified split-spoon sampler The sampler will be driven a maximum of 18 inches using a 140-pound hammer with a 30-inch drop All 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 All 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 Shallow Groundwater Monitoring Well Installation One boring will be converted to groundwater monitoring wells by installing 2-inch diameter, flush-threaded, Schedule 40 PVC casing with 0 020-inch factory-slotted screen Approximately 20 feet of 0 020 slotted screen will be placed at the bottom 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 well A bentonite seal will extend three feet above the sand pack The monitoring well will be completed with neat cement from the bentonite seal to ground surface The well casing will be topped with a locking cap The wellhead will be contained in a watertight and traffic well box The boring logs will show well construction details Deep Groundwater Monitoring Well Installation Three borings will be converted to groundwater monitoring wells by installing 2-inch diameter, flush-threaded, Schedule 40 PVC casing with 0 020-inch factory-slotted screen Approximately 5 feet of 0 020 slotted screen will be placed at the bottom 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