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Mr. Russell F. Chapin <br /> October 31, 1990 <br /> Page 3 <br /> soil in the aquifer. A 1- to 2-foot thick plug consisting <br /> of bentonite pellets will be placed above the sand to <br /> prevent against cement entering the sand pack. The <br /> remaining annulus will be backfilled with a mixture of neat <br /> cement and powdered bentonite (<5%) to grade. <br /> A cast-aluminum utility box with a PVC apron will be <br /> placed over each well head and set in concrete flush with <br /> the surrounding grade. Utility boxes such as these have a <br /> watertight seal to protect against surface-water <br /> infiltration; a specially designed wrench is required to <br /> open it. This design discourages vandalism and reduces the <br /> possibility of accidental disturbance of the well . Each <br /> well head will also be fitted with a locking well cap to <br /> protect against unauthorized disturbance of the well . <br /> After the wells are constructed, they will be subjected <br /> to a subjective inspection. A bailer will be lowered to the <br /> groundwater surface and retrieved. The water will be <br /> examined for floating product, sheen, or odor . If floating <br /> product is detected, the well will not be developed or <br /> sampled. Those wells which do not show floating product <br /> will be developed by surging with vented surge blocks and <br /> extensive pumping. After development and stabilization of <br /> the wells, they will be purged until a minimum of three well <br /> volumes of water are removed from each well and stable field <br /> readings of pH, conductivity, and temperature are obtained. <br /> The wells will then be sampled using clean bailers . <br /> Groundwater samples will be analyzed for TPH(g) , BTEX, and <br /> organic lead. <br /> ROGER FOOTT ASSOCIATES, 'dN0. <br />