2013-10-17_PERMIT FILE - C1982056A (4)

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that subsidence of AVF areas will not materially damage or diminish reasonably foreseeable uses of structures or resources, including overlying ranchlands. It should be noted that the Kaman Tempo report was prepared in 1982, and since that time, land management practices have not changed significantly, i.e. large acreage ranches to meet the economic requirements of the marketplace. This ownership pattern continues in the Twentymile Park Basin. Owners of those areas to be subsided include TC, the State of Colorado, and Camilletti and Sons. TC contracted with SubTerra, Inc. to expand the previous subsidence predictions to further evaluate impacts to Fish Creek and its associated AVF areas for continued mining in the NMD. This report is presented in Exhibit 7e -6, Twentymile Coal Company, AVF Subsidence Study, Final Report. The results of subsidence modeling show an additional 7.3 acres will be flooded as a result of mining in Panels 16- and 17 -Right during the low flow period. During spring runoff, up to 12.3 acres will be flooded. SubTerra also analyzed the creek from Stations 5+ 00 to 100 +00, relative to subsidence- related change in the gradient of Fish Creek channel. The analysis included evaluating the gradient both before and after mining. The result of this analysis is presented on Tables 2 and 3 in the study. The report narrative also includes discussion of anticipated changes in gradient. More recently, a supplemental subsidence evaluation was completed for mining of Panels 12- through 16 -Left (WMD) under Fish Creek and its associated AVF. The results of this evaluation are presented in Exhibit 25Z, Western Mining District Subsidence Review (PR09 -08). This evaluation indicated similar subsidence effects to those experienced for the SWMD, EMD, and NMD, with temporary flooding of approximately 39.9 acres under normal flow conditions, and a total of 66.9 acres under high -flow (spring runoff) conditions. Based on subsidence modeling, the maximum change in stream gradient would be 0.7 percent (0.7 feet or 8.4 inches in 100 feet). The two landowners would potentially be affected by undermining and subsidence of Fish Creek and its associated AVF; Camilletti and Sons, and the State of Colorado. Camilletti and Sons own property within the Permit Area that will be affected by mining of Panels 15- through 24- Right. Fish Creek and its associated AVF will be affected within their property boundaries by mining of Panels 14- through 19- Right. Approximately 0.5 acres will be flooded during low -flow conditions, and 2.3 acres during high -flow conditions. Personal communication (April and May, 2003) with Mr. Frank Camilletti, of Camilletti and Sons indicates that this acreage is not critical to the continued operation of the ranch and will not materially damage or adversely affect their operations. This is due to the fact that this parcel of land is within a narrow canyon and is not conducive to flood irrigation for the production of hay crops. This area is not cropped and is treated as unimproved rangeland. The State of Colorado is the surface owner of lands within the permit boundary to be undermined and subsided during mining of the 13- though 24 -Right Panels and the 14- through 17 -Left Panels. Fish Creek and its associated AVF will be affected by mining in the 17 -Right Panel. As presented in Exhibit 7e -6, a total of 4.4 acres will be flooded by 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 management practices established for haying this area. The land is treated as unimproved rangeland utilized for grazing by the lessee. Cross - Mountain Ranch, LLC previously owned the property within the Permit Area that will be affected by mining of Panels 12- through 17 -Left, and Fish Creek and its associated AVF will be affected by mining of Panels 12- through 16 -Left. TC purchased, and now owns the former subject Cross Mountain Ranch, LLC properties. As presented in Exhibit 25Z a total of 39.9 acres will be flooded under normal flow conditions by mining of these panels. 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 management practices established for haying this area. The land is treated as unimproved rangeland utilized for grazing by the lessee. Stock Ponds and Surface Water Monitoring Sites - There are a number of small stock ponds located throughout the NMD and WMD, as shown on Map 23B. The ponds are constructed of earthern materials and are typically fed by spring runoff or rain - storms. TC has undermined and subsided similar stock ponds during mining of reserves located in the EMD and NMD. No material damage to the ponds resulted from the mining TR13 -82 2.05 -184.9 02/28/13