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1 ARCADIS GERAGHTY&MILLER <br /> i <br />' preventative against water within the augers entering the Simul robem water sampling port <br /> The condom is destroyed as the probe is pushed into the soil sampling zone at the bottom of <br /> the auger Once the sampling depth was reached, the Simulprob6rm was driven approximately <br /> 18-21 inches into the subsurface by the drill-rig hammer to collect the soil core The <br /> Simulprobe7m was then pulled back approximately 2 to 3 inches to retract the sliding Drive <br />' Shoe and expose the Circular Screen(Figure 4-1) The nitrogen gas was then allowed to bleed <br /> offto the atmosphere at ground surface which allowed water to enter the Simulprobe7m under <br />' the depth-specific hydrostatic pressure After waiting approximately V2-hour for the <br /> SimulprobeTM to fill with water, it was repressurized with nitrogen gas to minimize potential <br /> infiltration of borehole water as it was raised through the augers The Simulprob6rm was <br /> depressurized at the surface, and a short length of 5116-inch OD Teflon tube was inserted <br /> through the bottom of the reed valve to drain and collect a water sample from the bottom of <br /> the Water Canister (Figure 4-1) The groundwater samples were stored in clean, glass bars <br /> provided by the on-site mobile laboratory and returned to the on-site mobile laboratory under <br />' proper chain-of-custody protocol for possible analysis Following collection of the water <br /> sample, the Simulprobe "4 core barrel was then disassembled and the soil core removed The <br /> soil samples were preserved and evaluated following the procedures described above <br />' 4 2 4 Groundwater Well Installation <br /> Based on the analytical results from the soil and water samples collected using the <br /> Simulprob6m,groundwater monitoring wells NP-1 and NP-2 were constructed as triple-nested <br /> piezometers using 1-mch diameter, schedule 40 PVC casing The slotted (0 02 inch slot size) <br /> sections for well NP-1 extended from approximately 116 feet bgs to 111 feet bgs (lower well), <br />' 75 feet bgs to 65 feet bgs (middle well), and 37 feet bgs to 22 feet bgs (upper well) The sand <br /> filter pack, consisting of clean #3 sand, was placed adjacent to each slotted section and <br /> ' extended approximately three feet above each slotted section Approximately four feet of <br /> bentonite pellets were placed above each sand filter pack and hydrated A cement/bentonite <br /> ' 15 <br />