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B-2 <br /> description. That part of the soil sample collected in brass tubes within the California-type sampler is <br /> stored at 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 <br /> for further examination and for verification of the field classification. Logs of the borings indicating the <br /> depth and identification of the various strata, the N value, and pertinent information regarding the method <br /> of maintaining and advancing the borehole are made. <br /> 1.5 Soil Sample Screenine/hNu Portable Photoionization Detector Method <br /> Atter 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 FID equipped with a 10.2 eV lamp. The sample comer of the bag is <br /> opened and the detector probe immediately placed within the headspace. The highest observed reading is <br /> recorded. <br /> 1.6 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 /> 1.7 Monitoring Well Development <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 during well development. All <br /> developed water is placed in drums on-site for later disposal. <br /> 1.8 Ground Water Sampling <br /> At least three wetted casing volumes of liquid are removed from each well by bailing with a clean <br /> disposable bailer. A liquid sample is then collected from each well with a cleaned disposable bailer and <br /> LRP015.809 <br />