Laserfiche WebLink
remain level to function correctly. Given the anticipated subsidence projected for the panel, it was determined that <br />by moving the switch prior to mining 9 Right would prevent any problems with the switch. <br />After subsidence is completed, the structures will be inspected to determine if any additional repair work will be <br />needed to return them to their pre -mine condition. This work could entail replumbing or replacing damaged <br />components or structures on an as- needed basis. <br />Generally, TCC is not expecting that the wooden lines, both H- structures and sing pole, will be materially damaged <br />as a result of undermining and subsiding them. TCC has generated site - specific data for these powerlines through <br />its mining in the Southwest Mining District. In the East and Southwest Mining Districts, both types of powerlines <br />were undermined and subsided with no significant impact to the lines or the structures. The results of TCC's <br />monitoring of this structure has been presented in TCC's semi - annual subsidence reports and in Exhibit 7G. <br />Twentymile did subside this line during the mining of panel 9 Right. There was no significant problems <br />encountered during the mining episode. The powerline maintained its integrity; this substantiates Twentymile's <br />opinion that subsidence will not materially damage the line. <br />NMD (Panels 12 Right through 16 Right) (PR 99 -05) <br />Subsidence Control Plan <br />The proposed mining in the EMD should not result in the material damage or diminution of reasonably foreseeable <br />use of structures or resources in the five -year mine plan. The structures within the five -year mine plan area include <br />County Road 33, telephone line (U.S. West), Twentymile Sandstone, Foidel, and Fish Creeks. <br />County Road 33 <br />In reference to County Road 33, Twentymile has gained recent experience with undermining and subsiding both <br />County Road 27 and County Road 33. The experience indicates that either tensional or compressional fractures <br />may be manifested in the road surface. This results in either cracking or buckling of the road surface. In either <br />case, gravel is brought in to provide a temporary repair to the roads' surfaces. The permanent repair program, <br />asphalt patches or overlay, insures that material damage or diminution of reasonably foreseeable use of the road <br />does not occur. <br />Union Pacific Railroad <br />In reference to the Union Pacific Railroad (formerly Southern Pacific), this rail line will be subsided, but no <br />material damage or diminution of reasonably foreseeable use is anticipated. The subsidence projections indicate <br />there will be grade change within the course of the track. However, Twentymile or representatives of the railroad <br />will be inspecting the track on a daily basis during the subsidence period. In the event there are grade changes <br />which could disrupt traffic, the railroad tracks will be repaired accordingly. The anticipated repair would focus on <br />releveling the track and having a slow -speed restriction on during that time period. The monitoring and repair of <br />the track will occur until mining of panels 5 Right through 9 Right in the Eastern Mining District have been <br />completed. During the repair of the track, it is anticipated additional ballast will be required to relevel the track. <br />This will be replaced on an as- needed basis. Either Twentymile or Union Pacific will stockpile additional ballast <br />for the repair work. The track has been successfully subsided where it overlies the 9 Right panel. No significant <br />problems were encountered during the mining episode." <br />AP <br />P���T�� JUN 2 5 2GQ0 <br />PR 99 -05 2.05 -197.2 2/24/99 <br />