2009-10-30_PERMIT FILE - C1982056A (5)

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_ Havden-Gore Pass Lioe • In looking at the Hayden-Gore Pass line two components of material damage have to be assessed, those being: 1} promptly restoring power, and 2)maintaining the structures. Prior to subsidence, the metal towers and their footings were inspected by qualified representatives of the lines' joint owners. The inspection identifies the following: 1) structural defects, 2) missing/damaged parts, 3) loose bolts, 4) stressed members, and 5) any other visible condition which might impact the tower response to subsidence. Records were established detailing their condition prior to subsidence and any necessary repairs were noted and completed. While subsidence occurred the towers were monitored as per the plan described previously. [f a footing subsided more than 1 inch in a twenty-four hour period the joint owners or their designee were notified of this circumstance. The notification was made as soon as TCC is aware of the circumstance. The results of the monitoring were used to determine the extent of differential settling and the potential for this to cause structural problems. The data was used by joint owners in determining structural integrity of the towers Material damage did not result from the mining of Panels 9 Right through 7 Right, for the Hayden-Gore Pass transmission line. The worst case consequences projected for the line included tilting and deformation of the metal structure, cracking of the foundation, detachment of the line from the connectors, and loss of service. In regards to the tilting and/or deformation of the structure, material damage can be prevented by making prompt repairs to the structure. The repair plan for the structures was directed by the joint owners and addressed the need to: 1) repair/replace deformed structural members, 2)realignment of structural members to correct tilting, 3)examining foundation to determine if replacement or structural enhancements (i.e. placing structural bands around foundation) were required, 4) placement of additional support/structural members, or 5) replacement of metal structure with wooden structure. Once the repairs or replacement were completed, if needed, the structure was returned to its pre- mine condition. The loss of service will be addressed by the systems ability to reroute power promptly and/or reroute power prior to subsidence. The utility determined which was the preferred option for addressing temporary service disruptions as they have the expertise to manage power routing through their system. The ability to reroute power ensured no material damage will occur from loss of service on the Hayden-Gore Pass line. Also, the information generated from mining the 9 Right panel will be used to further enhance the maintenance program for the structures. TCC did not anticipate material damage occurring in the event that any of the powerlines were to detach from their connectors and fall to the ground. The lines are constructed to withstand wind and changing temperature conditions. These design considerations made it very unlikely that any of the lines will ever detach and fall to the ground. In the event that this occurred the main concern that would arise is for either the train or someone from the public being stuck by the line. Of course the potential for this to occur is extremely remote and highly unlikely to occur. The powerline and railroad track inspection programs instituted for the EMD ensured that this situation did not arise. The daily inspection of the powerlines included looking at the connectors to determine their integrity. Any problems noted could be remedied immediately by repair crews. This further reduced the potential for the line becoming detached and falling to the ground. During active mining the line will be inspected during each l2 hour shift, which further minimizes the potential for anyone coming into contact with a powerline. Additionally, prior to the train coming over the subsided section the track was inspected visually, thus providing confirmation that the track is safe to travel. A down line would be seen by the party inspecting the line and appropriate repairs initiated prior to the train proceeding into or of the mine site. Also, the line has ground-fault interruption protection, which will cause the line to go dead in the event it hits the ground. During longwall mining of panels 9 Right through 7 Right, the lines remained attached to their connectors and none of the above had to be put in place. Wolcott Tam-Wolcott Line Public Service Company's Wolcott Tap-Wolcott Transmission line had a gang switch located within the area to be subsided and TCC relocated it prior to subsiding the powerline in panel 9 Right. The switch was relocated outside of the area at a location chosen by Public Service Company. The reason for relocating the switch was that it APPROVED APR 2 4 2000 Permit Renewal No. 3 2.05-196 12/10/98