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

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mining in the damaged area, an asphalt patch was completed as a permanent repair. For both areas, a crack sealant was used to fill minor cracks in the road. Refer to the semi - annual Subsidence Report for additional details. • Powerlines - TCC successfully undermined and subsided several powerlines during the mining of Panels 9 -, 6 -, 5 -, 4 -, 3- and 2- Right. The powerlines were monitored under the approved plan, and the resulting data has been presented and summarized in the semi - annual Subsidence Reports. The monitoring results confirm that the lines were subsided, but did not fail, nor were there any foundation failures. Experience and monitoring data verified the initial contention that no significant impacts would result from undermining and subsiding powerlines. This same reasoning was applied to the powerlines undermined by Panels 18- and 19- Right, with the same result. Given TCC's experience, it is reasonable to assume that undermining and subsiding the 69KV powerline that overlies Panels 13- through 17 -Left should have no adverse effects on the powerline. The subsidence prediction for the powerlines (NMD) is presented in Exhibit 7e -7, Twentymile Coal Company, 19 -Right Powerline Study, Final Report, prepared by SubTerra, Inc. in May 2003. As presented in the Report, subsidence was projected to vary from 36 to 48 inches over the 19 -Right Panel. The powerlines are located closer to the 18 -Right gateroad, which is the reason for the lower subsidence predictions, i.e. centerline of panel versus actual location. TCC worked with the utilities to devise a monitoring program for the affected powerlines, given the fact that the lines run the entire length of the panel, as opposed to cutting across the panel. The finalized plan was provided to the DRMS prior to undermining the structures. Although not indicated by the subsidence projections or historic experience, the power company elected to establish a new powerline in conjunction with system upgrades for their main south feeder line, with connections that would allow them to jumper around the existing powerlines if significant adverse subsidence impacts were to occur. Union Pacific Railroad Spur (formerly Denver & Rio Grande) - The Union Pacific railroad spur was undermined and subsided by TCC's mining of Panels 17- and 18 -Right in the NMD. The subsidence predictions for the railroad track are presented in Exhibit 7e -8. The maximum subsidence predicted for the panel was approximately 67 inches. Subsidence of the track required re- leveling the track, to the extent required, to assure no disruption of service to the mine. Ballast was stockpiled or hauled -in to be used in this work. If required for the creek crossings, fill material may be brought in from material that the UP has stockpiled during its normal maintenance activities. The material will be placed and remain until the UP removes the Energy Spur. No significant impact is anticipated to the track after the repair work is completed. This is substantiated by TCC's experience with re- leveling the track that passed over Panels 9- through 7- Right, and 12 -, 13 -, and 14- Right. Fish Creek and the Associated AVF — Based on TCC's previous experience and monitoring results for undermining and subsidence of Fish Creek and its associated AVF, no material damage or diminution of use is anticipated for Fish Creek for ongoing mining in the NMD and WMD. Exhibit 7e -6 contains the subsidence predictions (NMD) for the creek. TCC has gained a great deal of experience and data on the effects of undermining and subsidence for Foidel Creek, Middle Creek and Fish Creek as a result of recent mining in the SWMD (Panels 2- through 5- Left), EMD (Panels 2- through 10- Right), and NMD (Panels 12- through 19- Right). Undermining and subsidence has resulted in temporary ponding in subsided areas, minor localized changes in stream gradients, and excursion of flows from the defined channel into floodplain areas, particularly during high flows. Except for the one isolated period, when flows in Foidel Creek were temporarily interrupted for a period of 8 hours, due to ponding in a subsidence area, no significant damage or interruption of flows has been observed in any of the affected creeks. Similar effects are anticipated for Fish Creek as mining progresses through the NMD (Panels 17- and 18- Right) and into the WMD (Panels 12- through 16 -Left). Designated AVF areas along Fish Creek will be undermined and subsided by Panels 17- and 18 -Right (NMD) and Panels 12- through 16 -Left (WMD). The location of the AVF in relation to the panels is shown on Maps 23 and 23B. The area that TCC proposes to undermine in the NMD in the Fish Creek drainage is located in parts of III Sections 10 and 11 of T5N, R86W, and is identical to the area that P &M Coal Company was planning on undermining and subsiding in its proposed Fish Creek Mine. P &M contracted with the consulting firm of Kaman Tempo to prepare a report responding to the requirements of Rule 2.06.8(4). This report has been incorporated into Exhibit 7 -e2. The conclusions presented in the report are consistent with TCC's contention PRO9 -08 2.05 -184.8 04/29/09