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Landfill Gas Migration Monitoring Well Installation Report October 2009 <br /> Foothill Landfill Project No. 03160203 <br /> For proper identification during construction, the tops of the probe pipes were <br /> painted as follows to indicate depth: yellow for the deep probe pipe; blue for <br /> the intermediate probe pipe; and red for the shallow probe pipe. <br /> ® Each probe was completed with two 2-foot long rebar weights secured to the <br /> bottom of the probe with tie wire. Each probe also had a PVC end cap secured <br /> with stainless steel screws. <br /> • After drilling was completed, the total borehole depth was measured in the <br /> presence of Vector and EHD staff. <br /> Before placing the probes in the borehole, the total pipe lengths and the <br /> perforation lengths were measured in the presence of Vector and EHD staff, <br /> to confirm that the lengths were in accordance with the project's Plans and <br /> Specifications. Any necessary adjustements were performed by LFG Control <br /> personnel. <br /> The deep probe was then placed in the borehole (Photograph 29, Appendix B). <br /> Clean gravel pack was backfilled around the probe, extending six inches <br /> above the top of the probe pipe perforations. The depth to the top of the <br /> gravel pack was measured frequently during backfilling, until the desired <br /> depth (per the Plans and Specifications) was reached. <br /> ® Five feet of bentonite was placed above the gravel pack. The depth to the top <br /> of the bentonite plug was measured before placing the intermediate probe <br /> pipe. <br /> The remaining probes, gravel packs and bentonite seals were constructed in a <br /> similar fashion, according to the design shown in Figure 3. <br /> The installation of all the probes and backfill of the borehole with gravel pack <br /> and bentonite was observed by EHD inspectors. All probes were installed to <br /> design depth and specifications, except for those which were modified in the field <br /> ® in accordance with Title 27 Section 20925, where sand lenses in the native soil <br /> Vector Engineering, Inc. • 143E Spring Hill Drive• Grass Valley, CA 95945•(530)272-2448 <br /> 4 <br />