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' • i <br /> 21 August 2000 <br /> AGE-NC Project No 97-0343 <br /> Page 7 of 9 <br /> 42 SOIL SAMPLING <br /> Soil samples will be collected at five-foot )intervals, beginning at a depth of 5 feet bsg, utilizing a <br /> modified California split-spoon sampler and brass sleeves The sampler will be driven by dropping <br /> a 140-pound weight from a height of 30 inches (blow counts) The blow counts will be recorded on <br /> boring logs Upon soil sample retrieval, the middle brass sleeve will be removed from the sampler <br /> The ends of the brass sleeve will be immediately covered with Teflon or aluminum sheets, sealed <br /> with plastic end caps, secured with tape and immediately placed in a chilled container for <br /> transportation cinder chain of custody to a state-certified laboratory Each sample sleeve will be <br /> labeled with the boring location, sample depth, sample time, sampling date and sampler's initials <br /> During sampling activities, sample duplicates will be monitored for the presence of organic vapor <br /> using a photo-ionization detector (PID Thermo Environmental 580A, 10 0 eV, calibrated to <br /> isobutylene) and will be visually described on boring logs using the Unified Soil Classification <br /> System (USCS) <br /> All sampling tools and brass sleeves used for sample collection will be thoroughly rinsed with clean <br /> water after washing with a solution of Alconox All hollow stem augers will be steam-cleaned prior <br /> • to advancement in each borehole <br /> 43 WELL COMPLETION <br /> Soil borings will be single-completed as ground water monitoring wells utilizing 2-inch diameter <br /> schedule 40 polyvinylchloride (PVC) 0 020-inch slotted well screen and blank well casing Based <br /> on geologi c/hydrogeo logic conditions, a 20-foot length of well screen is anticipated for installation <br /> of monitoring wells, the bottom of the screen interval will be placed 15 feet below the water table <br /> A proposed well construction diagram is depicted in Figure 3 <br /> After installing the well casing, filter pack material consisting of pre-washed#3 Lonestar sand will <br /> be added through the screen interval to approximately two feet above the screened interval <br /> Following placement of the filter pack, the well will be surged to assist in settling the filter pack <br /> Additional sand will be added if settling occurs <br /> A nominal two-foot bentonite seal(bentonite chips)will be placed above the filter pack to minimize <br /> the potential for grout penetration into the screened section of the well The bentonite seal will be <br /> formed by pouring bentonite chips into the annulus and allowing them to settle on the filter pack <br /> Bentonite chips will be hydrated using approximately five gallons of tap water The bentonite chips <br /> will be allowed to hydrate for a minimum of one-half hour prior to grouting <br /> Advanced GeoEnvironmental,inc <br />