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B-2 <br /> Upon recovery, a portion of the soil sample is placed into a plastic bag and sealed for later screening with a <br /> photoiomzation detector(PID) Another portion of the soil sample is used for classification and description <br /> That part of the soil sample collected in brass tubes within the California-type sampler is stored at <br /> ' approximately 4°C for transport to the laboratory <br /> ' 1 4 Soil Classification <br /> As the samples are obtained in the field, they are classified by the crew chief/geologist in accordance with <br /> ' the Unified Soil Classification System (USCS) Representative portions of the samples are then retained for <br /> further examination and for verification of the field classification Logs of the borings indicating the depth <br /> ' and identification of the various strata, the N value, and pertinent information regarding the method of <br /> maintaining and advancing the borehole are made <br /> 1 5 Soil Sample Screenin hNu Portable Photwonization Detector Method <br /> After the soil sample plastic bags are brought to ambient temperature, the headspace vapors of the soil <br /> sample in the bag are screened with a PID equipped with a 10 2 eV lamp The sample corner of the bag is <br /> opened and the detector probe immediately placed within the headspace The highest observed reading is <br /> recorded <br /> 16 Monitoring Well Gravel Pack and Slot Size Selection <br /> ' The gravel pack is selected such that it will permit the development of a zone of higher hydraulic <br /> conductivity adjacent to the well screen but will reduce piping of the finer-grained formation materials into <br /> the well The slot size of the well screen is selected such that it will retain a minimum of 95 percent of the <br /> gravel pack material <br /> ' <br /> 17 Monitoring Well Develo meet <br /> ' After monitoring wells have been installed, each monitoring well is developed with a surge block and bailer <br /> (or pump) until the water produced is relatively sediment-free and until the conductivity, pH, and <br /> ' temperature stabilize If the well is pumped dry during the development process, recharge rates are <br /> recorded No water or chemicals are introduced into the monitoring wells dunng well development All <br /> ' developed water is placed in drums on-site for later disposal <br /> LRPO18 809 <br /> 1 <br />