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+� 4 . Tunneling shall be preformed by a fluid-cutting process (high pressure-low volume ) utilizing liquid clay i . e . bentonite . The clay lining will maintain tunnel stability and provide lubrication in order to reduce frictional drag while the pipe is being installed . In addition , the clay fluid must be totally inert and contain no environmental risk. The Contractor must also have a mobile vacuum spoils recovery vehicle on site to remove the drilling spoils from the access pits . The spoils must then be transported from the job site and be properly disposed off the site. The drilling spoils shall not, under any circumstances , be ' disposed into a sanitary sewer, storm , or other public or private drainage system . Spoils may be transported to the County's Solid Waste Facility and the cost of disposal shall be by the County. 5 . Liquid clay type colloidal drilling fluid shall consist of at least 10 percent of high-grade carefully processed bentonite to consolidate cuttings of the soil , to seal the walls of the hole, and to furnish lubrication for subsequent removal of cuttings . The slurry that is heavier than the surrounding material , is high .r in colloids of the bentonite type and it will deposit a thin filter cake of low permeability material on the walls of the bore. This will allow only a small amount of the fluid to pass into the surrounding soils and will stabilize the bore . The colloidal content of the fluid imparts excellent lubricating qualities to the slurry that is a distinct aid to the removal of the soil cuttings . 6 . Pneumatic or water-jetting methods will be considered unacceptable due to the possibility of surface subsidence . 7 . After an initial bore has been completed , a reamer will be installed at the termination pit and the pipe shall be pulled ' back to the starting pit. The reamer shall be capable of discharging liquid clay to facilitate the installation of the pipe into a stabilized and lubricated tunnel . 8 . A minimum of two (2 ) insulated #6 stranded tracer wire shall be installed along with the PE pipe . The tracer wire shall be tested for continuity upon completed installation . Should both tracer wires fail to test for continuity then the test shall be considered a failure and the wires shall be replaced . Tracing wires, #10 stranded conductor copper, shall be wrapped or .. affixed to the top of the pipe and fittings . 9 . Upon completion of boring and pipe installation , the Contractor shall remove all spoils from the starting and termination pits . ., All pits shall be restored to their original condition . 10 . The shoulders , ditches , banks , and slopes of roads and railroads crossed and paralleled shall not wash out before becoming consolidated . Restoration shall be as required by the jurisdictional authority and as specified within the Contract Document. END OF SECTION 3 - 11