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footings will be inspected by qualified representatives of the lines' joint owners. The inspection will identify the <br />following: 1) structural defects, 2) missing /damaged part, 3) loose bolts, 4) stressed members, and 5) any <br />other visible condition which might impact the tower response to subsidence. Records will be established <br />detailing their condition prior to subsidence and any necessary repairs will be noted and completed. <br />While subsidence is occurring, the towers will be monitored as per the plan described previously. If a footing <br />subsides more than 1 inch in a twenty- four -hour period, the joint owners or their designee will be notified of this <br />circumstances. The notification will be made as soon as TCC is aware of the circumstance. The results of the <br />monitoring will be used to determine the extent of differential settling and the potential for this to cause structural <br />problems. The data will be used by the joint owners in determining structural integrity of the towers. <br />Material damage is not anticipated for the Hayden -Gore Pass transmission line. The worst -case consequences <br />projected for the line included tilting and deformation of the metal structure, cracking of the foundation, <br />detachment of the line from the connectors, and loss of service. In regards to the tilting and /or deformation of the <br />structure, material damage can be prevented by making prompt repairs to the structure. The repair plan for the <br />structures will be directed by the joint owners and will address the need to: 1) repair /replace deformed structural <br />members, 2) realignment of structural members to correct tilting, 3) examining the foundation to determine if <br />replacement or structural enhancements (i.e. placing structural bands around foundation) are required, 4) <br />placement of additional support/structural members, or 5) replacement of metal structure with wooden structure. <br />Once the repairs or replacement are completed, the structure will be returned to its pre -mine condition. The loss of <br />service will be addressed by the systems ability to reroute power promptly and /or reroute power prior to <br />subsidence. The utility will determine which is the preferred option for addressing temporary service disruptions, <br />as they have the expertise to manage power routing through their system. The ability to reroute power ensures no <br />material damage will occur from loss of service on the Hayden -Gore Pass line. <br />TCC does not anticipate any material damage occurring in the event that any of the powerlines were to detach <br />from their connectors and fall to the ground. The lines are constructed to withstand wind and changing <br />temperature conditions. These design considerations make it very unlikely that any of the lines will ever detach <br />and fall to the ground. In the event that this occurred, the main concern that would arise is for either the train or <br />someone from the public being struck by the line. Of course, the potential for this to occur is extremely remote <br />and highly unlikely to occur. The powerline and railroad track inspection programs that will be instituted for the <br />EMD will ensure that this situation does not arise. The daily inspections of the powerlines will include looking at <br />the connectors to determine their integrity. Any problems noted can be remedied immediately by repair crews. <br />This further reduces the potential for the line becoming detached and falling to the ground. During active mining, <br />the line will be inspected during each 12 -hour shift, which further minimizes the potential for anyone coming into <br />contact with a powerline. Additionally, prior to the train coming over the subsided section, the track will be <br />inspected visually, thus providing confirmation that the track is safe to travel. A down line would be seen by the <br />party inspecting the line and appropriate repairs initiated prior to the train proceeding into or off the mine site. <br />Also, the line has ground -fault interruption protection, which will cause the line to go dead in the event it hits the <br />ground. <br />TCC undermined and subsided the line where it crosses over the 9 Right panel. The monitoring did not reveal any <br />significant impacts to the line. This substantiates Twentymile's position that no material damage will occur to the <br />line. <br />Wolcott Tap- Wolcott Line <br />Public Service Company's Wolcott Tap - Wolcott Transmission line has a gang switch located within the area to be <br />subsided and TCC relocated it prior to subsiding the powerline in panel 9 Right. The switch was relocated outside <br />of the area at a location chosen by Public Service Company. The reason for relocating the switch is that it must <br />APPROVED APR ti , 1998 <br />PR 97 -04 2.05.197.1 02/0/98 <br />