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CAMBRIA Well Development Wells are generally developed using a combination of ground water surging and extraction Surging agitates the ground water and dislodges fine sediments from the sand pack After about ten minutes of surging, ground water is extracted from the well using bailing, pumping and/or reverse air-lifting ' through an eductor pipe to remove the sediments from the well Surging and extraction continue until at least ten well-casing volumes of ground water are extracted and the sediment volume in the ground water is negligible This process usually occurs prior to installing the sanitary surface seal to ensure sand pack stabilization If development occurs after surface seal installation,then development occurs 24 to 72 hours after seal installation to ensure that the Portland cement has set up correctly ' All equipment is steam-cleaned prior to use and air used for air-lifting is filtered to prevent oil entrained in the compressed air from entering the well Wells that are developed using air-lift evacuation are not sampled until at least 24 hours after they are developed ' Ground Water Sampling Depending on local regulatory guidelines,three to four well-casing volumes of ground water are purged ' prior to sampling Purging continues until ground water pH, conductivity, and temperature have stabilized Ground water samples are collected using bailers or pumps and are decanted into the appropriate containers supplied by the analytic laboratory Samples are labeled, placed in protective ' foam sleeves, stored on crushed ice at or below 4°C, and transported under chain-of-custody to the laboratory Laboratory-supplied trip blanks accompany the samples and are analyzed to check for cross- contamination An equipment blank may be analyzed if non-dedicated sampling equipment is used F 1TEMPLATEISOPSIWELLS-GW WPD 1 1 1 1 Page 3 of 3