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The final area to be impacted by subsidence is the associated with the mining of Panel 16 Right. The State of Colorado is the surface owner of the parcel to be undermined and subsided. As presented above, a total of 4 acres ° will be flooded by the mining of this panel. As is the case for all the lands along Fish Creek to be undermined and subsided no flood irrigation system has been established to increase the productivity of the land nor are the management practices established for haying this area. The land is treated as unimproved rangeland utilized for grazing by the lessee. Ashley Imaoundment and Irrieation Ditch The Ashley impoundment is located in the SW/4 SW/4 of Section 15, TSN, R86W. This impoundment is of earthen construction and typically holds water throughout the years. The headgate for the irrigation ditch is located in the SE/4 NE/4 of Section 19, TSN, R86W. Twentymile has undermined and subsided sediment ponds during the mining of reserves located in the west part of the permit area. No material damage to the ponds resulted from the mining activity. It is anticipated that the Ashley impoundment will react in the same manner. If cracks developed in the embankment, they can be regaded and repaired to maintain the integrity of the impoundment. in reference to the smaller impoundment, TCC does not plan on any maintenance due to its current condition. If the owner maintains it prior to mining, then TCC will perform repairs as needed. NMD (Panels 17 Right through 2~Right)(PR 03-06) The proposed mining in the next segment of the NMD should not result in the material damage or diminution of reasonably foreseeable use of structures or resources in the five-yeaz mine plan. The structures, which will be subsided, within the five-yeaz mine plan area include stockponds, powerlines (Public Service, Western Area Power Association and Tri-State), Twentymile Sandstone, Union Pacific Railroad Track (formerly Southern Pacific), and ~ Fish Creek and its alluvial valley floor. Stock Ponds There aze a number of small stock ponds located throughout the NMD, as shown on Map 2313. The ponds aze constructed of earthem materials. The ponds aze fed by spring run-off or rain storms. Twentymite has undermined and subsided stock ponds during the mining of reserves located in the northern and eastern part of the permit area. No material damage to the ponds resulted from the mining activity. It is anticipated that the stock ponds will react in the same manner. If cracks developed in the embankments, they can be regraded and repaired to maintain the integrity of the pond. Powerlines t/" Twentymile successfully undermined and subsided a series of powerlines durinFF~~the mining of panels 9, 6, 5, 4, 3 and 2 Right. The powerlines were monitored per the approved plan~is-3ata was presented in semi-annual subsidence reports. The results of the monitoring show that the lin subsided, but they did not fail or experience foundation failure. This verified the contention that no impacts wiN be realized due to undermining and subsiding the lines. This same reasoning will be applied to the lines to be unTlermined by panel 19 Right. The subsidence prediction for the powerlines is presented in Exhibit 7e-7, Twentymile Coal Company, 19 Right Powerline Study, final Report, prepared by Sub Terra, Inc. in May 2003, As is shown, the subsidence will vary from 36 to 48 inches over the panel. The powerlines are located closet to the 18 Right gateroad which is the reason for the lower subsidence predictions, i.e. centerline of panel versus actual location. C ~ Twentymile is working with the utilities to devise a monitoring program for these lines given the fact that the lines run the entire length of the panel as opposed to cutting across the panel. The finalized plan will be forwazded to the DMG prior to undermining the structures. At this time it is not anticipated that another power route will be PR 03-06 2.05-184.7 05/07/03