ARCHIVED REPORTS_2005_5 - Laserfiche WebLink

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3 SUMMARY OF CONSTRUCTION 3.1 Perimeter LFG Extraction Wells 3.1.1 Description of Work TRG drilled and installed 13 perimeter LFG extraction wells between September 24 and October 1, 2004. Drilling of the 13 extraction wells, designated TGW-1 through TGW- 13, was performed by TRG using air-rotary drilling technology. Each well was completed in accordance with the design drawings supplied by BAS. The major components of well construction included the following: • Approximately 390 feet of vertical gas well drilling using 8-inch diameter air rotary drilling technology to complete 13 bore holes • Installation of approximately 364 linear feet of 2-inch diameter Schedule 80 PVC well casing The newly installed LFG extraction wells average approximately 30 feet in depth. Refer to Appendix A for well drilling/construction logs and Drawing 2 (Appendix C) for as- built well locations. 3.1.2 Construction Procedures The vertical LFG extraction well casings consisted of 2-inch diameter Schedule 80 PVC pipe, with the bottom 10 feet of each casing perforated with 1.5-inch long slots. The perforated portion of the well casing of each vertical extraction well is surrounded by pea- gravel backfill. The gravel backfill extends to the top of the perforated casing. A 2-foot thick layer of clean soil is placed on the top of the gravel backfill followed by a 5-foot- thick seal layer of hydrated bentonite chips. Bentonite slurry was placed above the bentonite chip layer to approximately 2-feet below ground surface(bgs). 3.1.3 CQA Activities EMCON observed and documented that the layout and depths of the LFG wells, well casing materials, backfill materials and procedures, and well pipe lengths were consistent with the approved construction plans and technical specifications. EMCON observed and EMCON/OWT N:\_LANDFIL\AWI Austin Road-Forward\2004 SVE CQA\text\report\CQA report final.doe Rev.0,1/5105 3-1