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Subsidence Handbook Volume III, Exhibit 15 <br />PIPELINES <br />Introduction <br />The Pitkin Mesa Pipeline approximately parallel's Steven's Gulch. The original pipeline built <br />in 1938, collects water from a series of springs located north of the permit boundary. <br />During various times the original pipeline (4 -inch diameter steel) has been replaced by a 6" <br />diameter PVC pipeline. The pipeline services approximately 160 domestic taps on Pitkin <br />Mesa. <br />Worst -Case Damage <br />Tensile and compressive strains at the ground surface caused by subsidence could <br />separate the joints of the pipeline and or break the pipeline. <br />Pre - Damage Monitoring <br />No pre- damage monitoring will be performed. The Applicant will assume the pipeline is in <br />good condition. <br />Post - Damage Monitoring <br />Post - Damage monitoring would involve inspecting the pipeline for leaks. <br />Mining Techniques <br />Mining near or under the Pitkin Mesa pipeline will not be limited. The applicant plans to <br />mitigate the risk of damage to the Pitkin Mesa pipeline by installing a schedule 80 6 -inch <br />diameter heat fusible high density polyethylene pipe (HDPE) adjacent to the existing Pitkin <br />Mesa pipeline. The new pipe will be placed in a trench excavated next to the existing <br />pipeline. The new pipe will replace the existing pipeline. The existing pipeline will be <br />capped and remain in place. <br />Repair Procedures <br />Sections of the pipeline would be replaced. <br />PR -14 49 03/14 <br />