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An intermediate liner system is proposed over the existing Austin Road Landfill. <br /> Horizontal collectors, spaced at approximately 200 feet on center, will be <br /> installed to collect landfill gas generated below the liner (see Drawing 13 of the <br /> JTD). The horizontal collector consists of perforated HDPE pipe installed in a <br /> gravel pack below the proposed liner system. A geotextile fabric will be installed <br /> in the gravel trench to prevent fine materials from entering and clogging the <br /> collector pipe. Additionally, the existing vertical landfill gas wells will be cut <br /> about five feet below the liner and connected to the horizontal wells with <br /> laterals. The horizontal wells will be extended through the edge of the in-place <br /> refuse prism on the north face to extract landfill gas while the site is filled. When <br /> the refuse in adjacent waste cells reach the height of the horizontal well stub- <br /> outs on the south face, the horizontal well can be extended to collect the gas <br /> generated in the new cells. This end of the horizontal collector will be <br /> connected to the looped header system located along Austin Road's southern <br /> boundary. <br /> As the new cells are filled, additional vertical extraction wells will be installed, as <br /> necessary, in phases to control surface landfill gas emissions. These wells may <br /> JMkk be extended as the fill progresses in the cell, or may be abandoned and replaced <br /> with new wells when the fill reaches the final grade elevation. <br /> As the fill progresses above the existing and now-lined refuse prisms, additional <br /> vertical extraction wells will be placed, as necessary, into the upper portions of <br /> the landfill to achieve the proper spacing required for surface emissions control. <br /> Permits will be obtained from the San Joaquin Valley Air Pollution Control <br /> District (SJVAPCD) and other appropriate agencies for the construction and <br /> operation of the gas system. <br /> The LFGES will most likely be installed in phases as the landfill expands and/or as <br /> regulatorily required. As the landfill expands, it is anticipated that most of the <br /> system will be installed, with the balance of the system completed as part of <br /> closure. During closure construction, the system will be taken off line in phases <br /> as the final cover system is installed; the system will be modified, as necessary, <br /> and will then be reconnected. <br /> In order to integrate the gas control system with the final cover, the following <br /> procedures are proposed for closure construction. <br /> Forward Landfill PCPCMP 3-12 <br /> L:\Allied\2000.193\Reports\FinaIPCPCMP:FL-sec3.doc:5/21/02 BRYAN A.STIRRAT 6 ASSOCIATES <br />