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09 January 2017 • AGE Project No. 00-0769 Page 6 of 9 3.0. FIELD PROCEDURES All field procedures will be overseen by an AGE representative under the supervision of a California Professional Geologist. Procedures for advancing soil borings, collection and analysis of soil-vapor and groundwater samples, boring abandonment, equipment decontamination and sample handling are presented below. 3.1. OFF-SITE BORING ADVANCEMENT AND SAMPLING Proposed off-site soil borings will be advanced to depths of 145 feet (135) and 165 feet bsg (133, B4, & 136) utilizing a truck-mounted, hollow-stem auger drill rig (CME-75 High Torque or CME-95) equipped with either 6.25-inch or 8.25-inch diameter hollow-stem augers. Direct push technology might also be attempted, collecting shallow grab groundwater samples at off-site locations. Grab groundwater samples will be collected at the following depths: • In proposed boring B3, at depths of 120-125 feet bsg, 140-145 feet and 160-165 feet bsg; • In proposed boring B4; at depths of 45-50 feet bsg, 80-85 feet bsg, 140-145 feet bsg and 160-165 feet bsg; • In proposed boring 135; at depths of 45-50 feet bsg, 80-85 feet bsg, 120-125 feet bsg and 140-145 feet bsg; and • In proposed boring 136; at depths of 45-50 feet bsg, 80-85 feet bsg, 120-125 feet bsg and 160-165 feet bsg. Upon reaching desired grab groundwater sample depths, a water sampling assembly will be advanced (pushed) four feet below total depth of boring, and then retracted to expose a temporary well screen. Groundwater samples will be extracted from the water sampling rods by utilizing a 1/2-inch diameter or smaller stainless steel bailer through the hollow center of rods into the screen section. Each grab water sample will be transferred into three laboratory-supplied, 40-milliliter (ml) volatile organic analysis (VOA) vials. After collection, the samples will be properly labeled, placed in a chilled container and transported under chain of custody to a CDPH-certified analytical laboratory for analysis for the constituents listed in Section 2.2. At the conclusion of groundwater sampling, all soil borings will be permanently sealed to prevent vertical migration of potential contaminants. Soil borings shall be abandoned by backfilling with cement grout from the total depth to surface grade. Borings advanced below the groundwater table will be abandoned with grout utilizing tremmie procedures. The top three-to six-inches of the boring abandonments will be completed flush to surface Advanced GeoEnvironmental Inc.