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B-2 <br />' 1.4 Monitoring Well Gravel Pack and Slot Size Selection <br /> The size of the gravel pack that is placed adjacent to the well screen is determined by the project manager <br /> based on an estimation of the distribution of grain size in the formation which is likely to be encountered <br />' within the uppermost saturated zone at the site Available geologic information is utilized in the selection <br /> of this grain size The gravel pack is selected such that it will permit the development of a zone of the <br /> higher hydraulic conductivity adjacent to the well screen but will not allow piping of the finer-grained <br /> formation into the well bore The slot size of the well screen is selected such that it will retain a <br /> minimum of 95 percent of the gravel pack material <br /> x.5 Monitoring Well Development <br />' After monitoring wells are installed, each monitoring well is developed after construction with a <br /> 1 75-inch-diameter bailer until the water produced is relatively sediment-free or until measurements of <br />' pH, specific conductance, and temperature stabilize No water or chemicals are introduced into the <br /> monitoring wells during well development All developed water is placed in drums on site for later <br />' disposal <br /> 11 <br /> .6 Ground Water Sam lin <br /> A minimum of 24 hours following well development, and after water levels have been allowed to stabilize <br />' in the well, 3 to 5 wetted casing volumes of liquid is removed from each well by bailing with a <br /> laboratory-cleaned teflon bailer Measurements of pH, specific conductance, and temperature are made <br /> at regular intervals during this procedure Removal of liquid from each well is continued until the <br /> measurement of pH, specific conductance, and temperature had stabilized A liquid sample is then <br /> ' collected from each well with a laboratory-cleaned, dedicated teflon bailer Each sample is appropriately <br /> labeled and stored on ice from the time of collection through the tune of delivery to the laboratory <br /> ' Ground water samples were transported to the laboratory and analyzed with in the EPA-specified holding <br /> time for the requested analyses <br /> ' <br /> 1.7 Handling and Disposal of Drilling Spoils <br /> Drilling spoils are temporarily stored in 55 gallon (DOT17H) drums at the site All drums used for <br /> ' temporary spoils storage are labeled with a temporary "Waste Material" sticker The sticker provides <br /> ' that following information <br /> A Warning of possible hazardous contents <br /> ® Laboratory analyses in progress <br /> ® Store No <br />