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1 <br /> ARCADIS GERAGHTY&MILLER <br /> grout was used as an annular seal between each nested well and as a surface seal The <br /> cement/bentomte grout was allowed to `set' overrught prior to installing the next nested well <br /> After the cement/bentomte grout settled overnight, bentonite clips and then clean#3 sand were <br />' added as needed to raise the annular seal to the depth necessary to construct the next nested <br /> well Approximately one foot of clean sand was placed above the annular seal for the lower <br />' and muddle wells, so that the overlying wells were placed on clean sand rather than bentonite <br /> clips or cement/bentonite grout The well construction diagram for well NP-1 is given in <br />' Appendix C <br /> The slotted (0 01 inch slot size) sections for well NP-2 extended from approximately <br /> 121 feet bgs to 116 feet bgs (lower well), 70 feet bgs to 60 feet bgs (middle well), and 47 feet <br />' bgs to 22 feet bgs (upper well) The sand filter pack, consisting of clean 42/12 sand, was <br /> placed adjacent to each slotted section and extended from approximately two feet (upper well) <br /> to five feet(lower well) above each slotted section A nu mum of approximately three feet of <br /> bentomte pellets were placed above each sand filter pack and hydrated A cement/bentonite <br />' grout was used as an annular seal between the lower well and the middle well and as a surface <br />' seal The cement/bentonite grout was allowed to `set' overnight prior to installing the middle <br /> nested well After the cement/bentonite grout settled overnight, bentonite chips and then clean <br /> 42/12 sand were added as needed to raise the annular seal to the depth necessary to construct <br /> the riddle nested well Due to the minimal vertical distance between the top of the riddle <br />' nested well and the bottom of the upper nested well in NP-2, an annular seal consisting of <br /> bentonite chips was used between these two wells rather than a cement/bentomte grout <br />' Approximately one foot of clean sand was placed above the annular seal for the lower and <br /> middle wells, so that the overlying wells were placed on clean sand rather than bentonite clips <br />' The well construction diagram for well NP-2 is given in Appendix C A flush-mounted, traffic- <br /> rated well protection (Christy) box was installed at the surface of each well with a watertight, <br />' locking cap to preclude tampering <br /> ' 16 <br />