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inhibiting paint acceptable to the Engineer. The protective enclosure <br /> covers shall be painted and labeled by the Contractor as directed by the <br /> Engineer. In addition, the Contractor shall provide a plastic tag that <br /> shall be- labeled and attached to each well head inside the protective <br /> cover. <br /> All riser pipe and screen, tubing, ceramic cups, bailers, and top and <br /> bottom caps for the wells, monitoring tubes, and lysimeters shall be <br /> decontaminated. Clean gloves shall be used during installation. The <br /> construction materials shall not be allowed to touch the ground surface <br /> following decontamination and prior to installation. <br /> A 3-foot 1/4 inch bentonite pellet or 5-foot volclay grout seal shall be <br /> installed directly above the filter around screen sections (wells and <br /> monitoring tubes) and the ceramic cups (lysimeters) , as specified by the <br /> Engineer. If water is not present in the boring, the bentonite pellets <br /> shall be hydrated after placement above the silica sand by pouring clean <br /> potable water, from a source approved by the Engineer, in the hole and <br /> allowing the bentonite to set for 15 minutes prior to grouting. If <br /> conditions are such that a bentonite pellet seal cannot be placed, <br /> Volclay grout, manufactured by the American Colloid Company, or an <br /> equivalent approved by the Engineer, shall be used as a substitute for <br /> the bentonite pellet seal . If a sealing material other than Volclay <br /> grout is proposed by the Contractor, the name of the product and <br /> manufacturer's brochures shall be submitted for review and approval by <br /> the Engineer. The Volclay grout or equivalent shall not be used unless <br /> verbal approval is given by the Engineer at the time of well , monitoring <br /> tube, or lysimeter installation. The Volclay grout or equivalent shall <br /> be mixed according to the manufacturer' s specifications, and shall be <br /> placed using the tremie method to form a minimum 5-foot seal . The <br /> tremie method shall consist of pumping the grout down the annular space <br /> through a pipe. The bottom of the pipe shall be placed as close as <br /> possible to the top of the filter but not so close that the filter will <br /> be damaged when the grout is pumped. Pumps, piping and other materials <br /> for mixing and pumping Volclay grout or an equivalent shall be provided <br /> by the Contractor. No additional payment will be made if Volclay grout <br /> or an equivalent is substituted for bentonite pellets. <br /> Above the bentonite pellet or Volclay grout seal to approximately 2 feet <br /> below ground surface, the entire length of the annulus around the riser <br /> pipes shall be backfilled with a grout slurry. The grout slurry shall <br /> be in accordance with the requirements of Section 2A-8. The grout <br /> slurry shall be tremied into place. <br /> The wells, monitoring tubes, and lysimeters shall be installed through <br /> the temporary outer drill casing. Only one well and monitoring tube <br /> shall be installed in each boring. Two lysimeters shall be installed in <br /> each lysimeter cluster boring. <br /> (MARLEY SSFS ) 2A-7 <br /> (CONTRACT NO. 13) <br /> (11654.652 ) <br />