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Report-Monitoring Well Abandonment Page 4 <br /> Former Karlson Trucking <br /> Project No. 191.2 <br /> August 6, 2002 <br /> All 6 monitoring wells were originally constructed with approximately 20 feet <br /> and of 2-inch i.d. PVC casing (including the screened interval). The screened <br /> interval was 15 feet long, and the gravel pack extended from the total depth <br /> of 20 feet to 1 foot over the slots (total of 16 feet). <br /> Twenty feet of casing has an internal volume of 0.44 cubic feet. The original <br /> boring diameter of the wells was 8 inches, and assuming the sand pack has a <br /> total effective porosity of 35 percent, the available space in the sand pack of <br /> each well is given as: <br /> Vol (c.£) = 0.35* [7E * (Boring Radius)2 * (Height of Sand Pack)] —Casing Volume <br /> = 0.35 * [[(7T* 16)/144] * 161 - 0.37 <br /> = 1.95 —0.37 = 1.58 cf <br /> The total volume that each well should accept is the sum of the casing <br /> volume plus the sand pack volume. This is 1.58 + 0.44, or 2.02 cubic feet. <br /> The following table gives the actual volume of grout pumped. <br /> Well Grout Pumped Variance from <br /> c Calculated Ideal <br /> MW-1 3.5 +1.48 <br /> MW-2 3.6 +1.58 <br /> MW-3 3.1 +1.08 <br /> MW-4 2.2 +0.18 <br /> MW-6 2.6 +0.48 <br /> MW-7 2.0 -0.02 <br /> The actual grout pumped exceeded the calculated space in all cases except for <br /> MW-7 where the volumes were essentially identical. This means that the <br /> grout completely filled the casing, the sand pack pore space, and some was <br /> forced in to the soil beyond the confines of the boring. <br /> After each well was grouted, the casing was cut off below grade, and the <br /> remaining hole around each well head was brought up to grade with native <br /> soil, or in the case of MW-1, with cement. <br /> 2937 Veneman Avenue,Suite B240 Geo-Phase Environmental Inc. Phone: (209)569-0293 <br /> Modesto, Ca 95356 Fax: (209)569-0295 <br />