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S [Lys Sampling Protocols Drilling A permit will be obtained as necessary for the monitoring well before drilling be tins. The monitoring well will be accomplished using a mobile mounted drilling rig employing the use of a hollow stent flight auger no less than 3 114-inch i.d. and 6 -inch o.d. All drilling equipment will be thoroughly steam-cleaned before drilling begins to prevent the introduction of contamination from off site and between borings to prevent cross contamination. Tile borings will be logged under the direct supervision of a registered engineering geologist using the Unified Soil CIassification System. The color, t?xture, moisture; plasticity (if applicable), consistency of the earth materials, blow counts, pertinent soil or bedrock characteristics, and any evidence of contamination will be noted. All water-bearing zones and the depths at which they were encountered will be noted on these logs. All borings will be drilled in such a manner as to prevent cross contamination between strata. Exploratory soil borings within the unsaturatr,d zone will be back- filled with a concrete slurry mixture. Borings into the saturated zone will be drilled to a maximum of 20 feet beneath the top of the aquifer being explored. Any perching layers encountered will be inves- tigated to a maximum thickness of five feet (5')and will be backfilled with concrete slurry, after a bentonite seat has been placed. If a deeper aquifer is to be investi- gated, conductor casing will first be grouted into place to seal off the upper aquifer(s), in series, if necessary, and drilling will proceed through the conductor casing after the grout has been allowed to set properly. If evidence of contamination is noted during the drilling, the drilling will he halted until the responsible profes- sional determines the advisability of deeper drilling. Upon termination, the boring into the saturated zone will be completed as a moni- toring well and backfilled with concrete grout, after a bentonite seal has been placed. The borinn for the monitoring well will be of a diameter at least four inches (4") greater than the two inch (2") diameter of the well casing to be used.