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30 minutes before filling the remaining annulus with cement- <br /> bentonite grout. Alternatively, fine sand (Lonestar No. 30 <br /> or equivalent) may be used to prevent the cement-bentonite <br /> grout from penetrating into the filter pack. Cement- <br /> bentonite grout (approximately S percent bentonite) will be <br /> emplaced in the annular space from the top of the mortar <br /> sand to the ground surface. <br /> After the cement-bentonite grout hris cured for a minimum of <br /> 24 hours, the monitoring wells will be developed by air <br /> lifting, surging, and/or pumping until the pumped water is <br /> clear (to be approximately 4 hours) . <br /> After development, a stainless steel submersible pump will <br /> be installed in the monitoring well. <br /> DISPOSAL OF CUTTINGS AND FLUIDS <br /> The drill cuttings, drilling mud, and fluids generated dur- <br /> ing drilling, development, and sampling of the newly con- <br /> structed wells will be disposed of onsite. The water will <br /> be discharged to the stormwater collection system and the <br /> drill cuttings and drilling mud will be disposed of on the <br /> McCormick and Baxter site. <br /> ROUTINE FIELD MEASUREMENTS <br /> The following paragraphs describe the routineP rocedures <br /> that will be followed to obtain field measurements during <br /> the McCormick and Baxter investigation. The methods de- <br /> scribed below will be applied in conjunction with the quali- <br /> ty assurance procedures described in Appendix B. <br /> SURVEYING <br /> Each of the new monitoring wells will be surveyed by a State <br /> licensed land surveyor. The top of well casing will be sur- <br /> veyed for elevation to the nearest 0 . 01 foot. All casing <br /> level measurements will be in relation to mean sea level. <br /> The wells will be horizontally located relative to the state <br /> plane coordinate system to an accuracy of one foot and re- <br /> corded on the site map. The purpose of surveying the moni- <br /> toring wells is to establish a common datum from which to <br /> calculate the water level elevation. <br /> WATER LEVEL MEASUREMENTS <br /> One day each month, the water level in all monitoring wells <br /> will be measured relative to the top of the well casing. <br /> Electric sounders or chalked steel tapes will be used to <br /> measure to the nearest 0 . 01 foot. The sounder cable or tape <br /> will be decontaminated before and after use at each well. <br /> A-2 <br />