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that subsidence of AVF areas will not materially damage or diminish reasonably foreseeable uses of structures <br /> or resources, including overlying ranchlands. It should be noted that the Kaman Tempo report was prepared in <br /> 1982, and since that time, land management practices have not changed significantly, i.e. large acreage ranches <br /> • <br /> to meet the economic requirements of the marketplace. This ownership pattern continues in the Twentymile <br /> Park Basin. Owners of those areas to be subsided include TCC, the State of Colorado, Camilletti and Sons, and <br /> Cross - Mountain Ranch, LLC. <br /> TCC contracted with SubTerra, Inc. to expand the previous subsidence predictions to further evaluate impacts to <br /> Fish Creek and its associated AVF areas for continued mining in the NMD. This report is presented in Exhibit <br /> 7e -6, Twentymile Coal Company, AVF Subsidence Study, Final Report. The results of subsidence modeling <br /> show an additional 7.3 acres will be flooded as a result of mining in Panels 17- and 18 -Right during the low <br /> flow period. During spring runoff, up to 12.3 acres will be flooded. SubTerra also analyzed the creek from <br /> Stations 5+ 00 to 100 +00, relative to subsidence - related change in the gradient of Fish Creek channel. The <br /> analysis included evaluating the gradient both before and after mining. The result of this analysis is presented <br /> on Tables 2 and 3 in the study. The report narrative also includes discussion of anticipated changes in gradient. <br /> More recently, a supplemental subsidence evaluation was completed for mining of Panels 12- through 16 -Left <br /> (WMD) under Fish Creek and its associated AVF. The results of this evaluation are presented in Exhibit 25Z, <br /> Western Mining District Subsidence Review (PR09 -08). This evaluation indicated similar subsidence effects to <br /> those experienced for the SWMD, EMD, and NMD, with temporary flooding of approximately 39.9 acres under <br /> normal flow conditions, and a total of 66.9 acres under high -flow (spring runoff) conditions. Based on <br /> subsidence modeling, the maximum change in stream gradient would be 0.7 percent (0.7 feet or 8.4 inches in <br /> 100 feet). <br /> Three landowners would potentially be affected by undermining and subsidence of Fish Creek and its associated <br /> AVF; Camilletti and Sons, the State of Colorado, and Cross - Mountain Ranch, LLC. Camilletti and Sons own <br /> property within the Permit Area that will be affected by mining of Panels 15- through 24- Right. Fish Creek and <br /> its associated AVF will be affected within their property boundaries by mining of Panels 14- through 19- Right. <br /> • Approximately 0.5 acres will be flooded during low -flow conditions, and 2.3 acres during high -flow conditions. <br /> Personal communication (April and May, 2003) with Mr. Frank Camilletti, of Camilletti and Sons indicates that <br /> this acreage is not critical to the continued operation of the ranch and will not materially damage or adversely <br /> effect their operations. This is due to the fact that this parcel of land is within a narrow canyon and is not <br /> conducive to flood irrigation for the production of hay crops. This area is not cropped and is treated as <br /> unimproved rangeland. <br /> The State of Colorado is the surface owner of lands within the permit boundary to be undermined and subsided <br /> during mining of the 13- though 24 -Right Panels and the 14- through 17 -Left Panels. Fish Creek and its <br /> associated AVF will be affected by mining in the 17 -Right Panel. As presented in Exhibit 7e -6, a total of 4.4 <br /> acres will be flooded by mining of this panel. As is the case for all the lands along Fish Creek to be undermined <br /> and subsided, no flood irrigation system has been established to increase the productivity of the land, nor are <br /> management practices established for haying this area. The land is treated as unimproved rangeland utilized for <br /> grazing by the lessee. <br /> Cross - Mountain Ranch, LLC owns property within the Permit Area that will be affected by mining of Panels 13- <br /> through 17 -Left, and Fish Creek and its associated AVF will be affected within their property boundaries by <br /> mining of Panels 14- through 16 -Left. As presented in Exhibit 25Z a total of 39.9 acres will be flooded under <br /> normal flow conditions by mining of these panels. As is the case for all the lands along Fish Creek to be <br /> undermined and subsided, no flood irrigation system has been established to increase the productivity of the <br /> land, nor are management practices established for haying this area. The land is treated as unimproved <br /> rangeland utilized for grazing by the lessee. <br /> Stock Ponds and Surface Water Monitoring Sites - There are a number of small stock ponds located <br /> • throughout the NMD and WMD, as shown on Map 23B. The ponds are constructed of earthern materials and <br /> are typically fed by spring runoff or rain - storms. TCC has undermined and subsided similar stock ponds during <br /> mining of reserves located in the EMD and NMD. No material damage to the ponds resulted from the mining <br /> PR09 -08 2.05 -184.9 09/29/09 <br />