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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, which is heavier than the surrounding material, is high 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 soil and will also stabilize the bore. The colloidal content of the fluid imparts excellent lubricating qualities to the slurry, which is a distinct aid to the removal of the soil cuttings. Pneumatic or water -jetting methods will be considered unacceptable due to the possibility of surface subsidence. After an initial bore has been completed, a rearner will be installed at the termination pit and the HDPE 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. A minimum of one (1) insulated 45 trace wires shall be. installed along with the HDPE. The trace wire shall be tested for continuity upon completed installation. 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. Restoration of Paved, Improved and Unimproved Areas The shoulders, ditches, banks and slopes of roads and railroads crossed and paralleled shall be restored to their former condition and properly sodded so that they shall not wash out before becoming consolidated. Restoration shall be as required by the jurisdictional authority and as specified within the Contract Document. Road and railroad crossings and parallel installations are to be continuously maintained until the completion of the work. No direct compensation shall be paid for Contractor's repair or maintenance of crossings and parallel installations. • END OF SECTION ' 02320-3 DADIVISION 2!02320 Insiallation by Directional Boring.rloc