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25 October 2016 <br />AGE Project No. 11-1847 <br />Page 6 of 8 <br />advanced to a depth of approximately 40 feet bsg for installation of a 2-inch diameter <br />shallow groundwater monitoring well. <br />Beginning at depths of 20 feet bsg from offsite soil borings B-14, B-15, B-16. B-17, MW-11 <br />and MW-12, relatively undisturbed soil samples will be collected from all soil boring <br />locations at 5-foot intervals using a California modified split-spoon sampler fitted with 2- <br />inch diameter, 6-inch long steel sleeves. Upon removal from the sampler, the sample <br />sleeves will be separated with a knife for logging purposes. Soils sampled in the borings <br />will be visually classified by an AGE geologist in accordance with the Unified Soil <br />Classification System (USCS). Additionally, soil samples will be field screened for the <br />presence of volatile organic compounds using an organic vapor meter (OVM), equipped <br />with a photo-ionization detector (PID). Soil sample descriptions and OVM readings will be <br />recorded on a log for each boring. <br />Upon reaching desired grab groundwater sample depths, a water sampling assembly will <br />be advanced (pushed) four feet below total depth of boring, and then retracted to expose <br />a temporary well screen. Groundwater samples will be extracted from the water sampling <br />rods by utilizing a 1/2-inch diameter stainless steel bailer through the hollow center of <br />rods into the screen section. <br />Each grab water sample will be transferred into three laboratory-supplied, 40-milliliter (m1) <br />volatile organic analysis (VOA) vials. After collection, the samples will be properly labeled, <br />placed in a chilled container and transported under chain of custody to Alpha Scientific <br />Corporation Environmental Laboratories (ASC), a State of California Department of Public <br />Health (CDPH)-certified analytical laboratory in Cerritos, California for analysis for the <br />constituents listed in Section 2.2. <br />3.2. WELL COMPLETION AND ELEVATION SURVEY <br />Upon reaching total depths at MW-11, MW-12 and MW-13, soil borings will be single- <br />completed as a groundwater monitoring well utilizing a 2-inch diameter, Schedule 40 PVC <br />blank well casing and 0.020-inch slotted well screen installed from 90 feet to 100 feet bsg <br />(MW-11 and MW-12, and screened from 20 feet to 40 feet bsg (MW-13). Diagrams of the <br />proposed monitoring well constructions are depicted in Figures 4 and 5. <br />After installing the well casing in each soil boring, a filter pack material consisting of pre- <br />washed #3 Lonestar sand will be added through the augers from total depth to <br />approximately 2 feet above the screened interval. Following placement of the filter pack, <br />the well will be surged to assist in settling the filter pack. Additional sand will be added if <br />settling occurs. <br />A three-foot to five-foot bentonite seal will be placed above the filter pack to minimize the <br />potential for grout penetration into the screened section of the wells. The bentonite seal <br />will be formed by pouring bentonite pellets into the annulus and allowing them to settle <br />on the filter pack. The bentonite pellets will be allowed to hydrate for the duration of time <br />.4dvanced GeoEnvironmental Inc.