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When daily monitoring indicates the track is damaged or the grade has changed, a slow speed <br />restriction is instituted. Re-leveling and repair of the track occurred in accordance with <br />mitigation plans required by Union Pacific Railroad. <br />Hayden-Gore Pass Powerline <br />When daily monitoring reveals structural tower damage, TCC will notify power repair crews <br />to stabilize and/or repair the damage. TCC will also notify the utility 30 days prior to <br />undermining, in addition to the Division requirement of 6 months notification of <br />undermining. TCC representatives have held discussions with the utility company and have <br />indicated to DRMS that re-routing capabilities and system redundancy will prevent end line <br />user power loss. Ground fault interruption capabilities are also in place to prevent a downed <br />line from remaining live if it were to fall to the ground or across County Road No. 33. <br />Twentymile Coal Company submitted a letter that confirms that end user power would not be <br />interrupted. This letter has been incorporated into the permit document in exhibit 7D-1. The <br />powerline was subsided without interruption or significant damage to the powerline towers. <br />Power company personnel inspected the powerline after subsidence had occurred and found <br />that deformation of the structures was within company specifications and did not require <br />Twentymile Coal Company to conduct repairs. Information regarding subsidence of the <br />Hayden-Gore powerline can be found in the 1997 and 1998 Subsidence Reports. <br />Archer-Havden Powerline and Western Area Power Administration and Tri-State & Public <br />Service Powerlines. <br />A monitoring plan for the Archer-Hayden Powerline was approved by the powerline operator, <br />as follows: TCC incorporated an engineering report into Exhibit 7e-7 of the PAP that <br />indicates the powerline can be subsided without interruption of power or significant damage <br />to the powerline towers. This prediction was based mainly on the operator's past success <br />undermining powerlines and the orientation of the powerlines over panel 19 Right being <br />parallel to the length of the panel. The pazallel orientation will result in independent <br />subsidence of each powerline tower and pole, rather than the simultaneous subsidence of <br />multiple towers and poles as done in the past. <br />Likewise, a monitoring plan was developed and approved for the Western Area Power <br />Administration and Tri-State & Public Service Powerlines. These lines also run the length of <br />19-Right panel; and, from previous experience, no significant damage or interruption of <br />power was anticipated during subsidence of these lines.13 <br />Existing Residences/Structures <br />Three residences were undermined and subsided during the mining of Eastern Mining District <br />longwall panels 6R and SR. One residence is occupied yeaz round, one is inhabited on a <br />limited basis, while the third is vacant and owned by Twentymile Coal Company. <br />is PAP page 191.6 and 7 <br />27 <br />