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U CLUSTER WELL SET 8A AND 8B The A zone well will be drilled north of former well MWl, which was destroyed prior to the over- excavation of contaminated soils. A limited access rig will be necessary due to overhead power lines. MW 8A will be drilled approximately 12 feet north of former well MWI. Drilling will utilize 8 inch hollow stem augers with 3 foot core barrels. The borings will be cored to the 18 foot depth base of Zone A sand. Core examination will determine the proper placement of i-5—foot length of 2 inch diameter, 0.01 inch slotted PVC screen. Blank Schedule 40 threaded PVC will be used to compete well MW8A to surface. #2112 sand will be used as the filter pack across the screen from bottom of the boring to six inches above the top of slots. Once the sand is in place the well will be surged to stabilize the sand pack and if necessary more sand will be added. Two feet of hydrated bentonite will then be used above the sand as a sanitary seal. Neat cement with less than 5% bentonite will be placed on top of the bentonite seal to surface, where surface security will be provided by the placement of a 6.inch diameter by 12 inch deep traffic rated water tight traffic box secured with a concrete shoulder, see Figure 4 for well construction details. A locking thermos type well cap will be placed at the casing top to secure the monitor well. The B zone well MW8B will be drilled approximately 3 feet west of the well MW8A, see Figure 3. Drilling will be as described above, with drilling/coring to the 27 foot depth. Core examination will determine the proper placement of the 5 foot length of 2 inch diameter, 0.02 inch slotted PVC screen. Monitor well construction will be similar to that described above except #3 sand will be used, see Figure 4 for well construction details. CLUSTER WELL SET 9A AND 9B The A zone well (MW9A) will be drilled approximately 40 feet west of former probe hole P9, see Figure 3. Drilling will utilize 8 inch hollow stem augers with 3 foot core barrels. The borings will be cored to the 18 foot depth base of Zone A sand. Core examination will determine the proper placement of 5 foot len h 2�inch diameter, 0.01 inch slotted PVC screen. Blank Schedule 40 threaded PVC will be used to compete well MW9A to surface. #2/12 sand will be used as the filter pack across the screen from bottom of the boring to six inches above the top of slot. Once the sand is in place the well will be surged to stabilize the sand pack and if necessary more sand will be added. Two feet of hydrated bentonite will then be used above the sand as a sanitary seal. Neat cement with less than 5% bentonite will be placed on top of the bentonite seal to surface, where surface security will be provided by the placement of a 6 inch diameter by 12 inch deep traffic rated Water tight traffic box secured with concrete shoulder, see Figure 4 for well construction details. A locking thermos type well cap will be placed at the casing top to secure the monitor well. The B zone well MW9B will be drilled approximately 3 feet east of the well MW9A, see Figure 3. Drilling will-be as described above, with drilling/coring to the 27 foot depth. Core examination will determine the proper placement of the 5 foot length of 2 inch diameter, 0.02 inch slotted PVC screen. Monitor well construction will: be similar to that described above except #3 sand will be used, see Figure 4 for well construction details. 5 Sanchez WORKPLAN 9-03