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gaps or flaws in the weld could be found. It should be noted that not a single fusion joint <br />was found to be defective. Only two of the joints made during the entire process were of <br />any concern, and these were immediately cut off the pipe and remade. These <br />questionable joints were the result of transient problems with the fusion machine. The <br />problems with the fusion machine were corrected before any production joints were <br />made. <br />In addition to the procedures described above, during construction it was <br />requested that ultrasonic testing of the fusion joints be pertormed. This request-came <br />from high-level Phelps Dodge personnel. An independent testing firm, RTD Quality <br />Services, in Houston, TX, was contracted to._pe.rform this testing...lt was notpossibleao::: :: ~ •. <br />test all of the fusion joints that had been. made because much of the HDPE pipeline had- <br />already, been installed and buried. All of the exposed joints, 22 total, were tested and <br />found to be free of defects. The ability to ultrasonic test HDPE joints has only recently <br />been developed, and was unknown to Wheeler previously. More information about the <br />testing done to the 24-inch HDPE pipeline is included in the Appendix to this report. <br />As the pipeline was being installed, it was decided to add bentonite "plugs" in the <br />pipe trench at two locations along the route. These plugs are used, to prevent <br />groundwater from traveling along the pipeline bedding for any distance: The: plugs, were <br />. formed from a bentorrite/earth mixture, inst'alled,around_the pipe perimeter,fora distance : -, _ _ <br />of approximately 10 feet. The plugs are located approximately at Station 4+OO.and <br />Station 24+00. <br />The existing 16-inch HDPE pipe in the PT was lifted and set onto newly formed <br />concrete supports so that the pipeline slopes continuously towards #5 Shaft to allow <br />complete draining of the pipeline. Anew drain line was installed in this section of pipe, <br />near #5 Shaft. Other minor work, such as installing a new sump, also occurred in this <br />area. <br />At the lower portion of the pipeline, near where it crosses the old discharge <br />pipeline, a section of gas pipeline had to be replaced. The gas pipe was made from 2- <br />7 <br />