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METHODS AND PROCEDURES Health and Safety Plan Field work performed by Delta and Delta's subcontractors at the site is conducted according to guidelines established in a Site Health and Safety Plan (SHSP) The SHSP is a document which describes the hazards that may be encountered in the field and specifies protective equipment, work procedures, and emergency information A copy of the SHSP is at the site and available for reference by appropriate parties during work at the site Locating Underground Utilities Prior to commencement of work on-site, Delta researches the location of all underground utilities with the assistance of Underground Service Alert (USA) USA contacts the owners of the various utilities in the vicinity of the site to have the utility owners mark the locations of their underground utshties Work associated with the boring and monitoring well installation is preceded by manual hand augering to a mvmmum depth of 5 feet below surface grade(bsg)to avoid contact with underground utilities Soil Sampling and Contamination Reduction Soil borings and soil sampling are performed under the direction of a Delta geologist The soil borings are advanced using a truck-mounted drill ng To reduce the chances of cross-contamunation between boreholes, all downhole drilling equipment are steam-cleaned between each boring To reduce cross-contamination between samples, the barrel sampler is washed to a soap solution and double-rinsed between each sampling event Upon recovery, a portion of the soil sample is placed into a plastic bag and sealed for later screening with a photosomzation detector(PID) Another portion of the soil sample is used for classification and description That part of the soil sample collected in the leading brass tube within the Cahfomma-type sampler is stored at approximately 4°C for transport to the laboratory Soil Classification As the samples are obtained to the field, they are classified by the geologist in accordance with the Unified Soil Classification System, Visual/Manual Method (USCS) Representative portions of the samples are then be retained for further examination and for venfication of the field classification Logs of the bonngs indicating the depth and identification of the various strata, the N value, and pertinent information regarding the method of maintaimng and advancing the borehole are made Soil Sample Screenin hNu Portable Photoionization Detector Method After the soil sample plastic bags have been brought to ambient temperature, the headspacc vapors of the soil sample in the bag are screened with a PID equipped with a 10 2 eV lamp The sample comer of the bag will be opened and the detector probe immediately placed within the headspace The lughest observed readings are recorded Monitoring Well Gravel Pack and Slot Size Selection The gravel pack is selected such that it will permit the development of a zone of higher hydraulic conductivity adjacent to the well screen but will reduce piping of the finer-grained formation materials into the well The slot size of the well screen is selected such that it will retain a minimum of 95 percent of the gravel pack material Monitoring Well Development After monitoring wells are installed, each monitoring well is be developed with a surge block and bailer (or pump) until the water produced is relatively sediment-free and until the conductivity, pH, and temperature stabilize if the well is pumped dry during the development process, recharge rates will be