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No irrigation headgates are located over or in close proximity to the panels. The AVF evaluation for this area <br /> documented that flood irrigation of the bottom lands is not practical, and that any enhancement of vegetative <br /> growth in these areas results from natural sub - irrigation. Subsidence of portions of the valley floor will increase <br /> the potential for sub - irrigation to occur, since seasonal flooding, ponding, and localized lowering of the ground <br /> surface will result in higher ground water levels relative to the subsided areas. Resulting saturated soil <br /> conditions may promote localized shifts in vegetation, with water tolerant species becoming more prevalent in <br /> areas of saturated soils. Conversion of transitional sage -grass meadow and pastureland to riparian habitat is a <br /> potential positive impact of the anticipated mining - related ground subsidence. <br /> Stock Ponds - There are a number of small stock ponds located throughout the NMD and WMD, as shown on <br /> Map 23B. The ponds are constructed of earthern materials, and are typically fed by spring runoff or rain - storms. <br /> TCC has undermined and subsided similar stock ponds during mining of reserves located in the northern and <br /> eastern parts of the Permit Area. No material damage to the ponds resulted from the mining activity. It is <br /> anticipated that the stock ponds in the NMD and WMD will react in the same manner. If cracks develop in the <br /> embarnkments, they can be repaired and regraded to maintain the integrity of the ponds. Similarly, if <br /> differential subsidence results in changes in the elevation of the pond embankments relative to the containment <br /> basins, minor repairs /reconstruction may be necessary to maintain water storage capacity and assure the <br /> integrity of the embankments. <br /> (ii) If the description of worst possible subsidence consequences, prepared in accordance with Section <br /> 2.05.6(6)(b)(i), determines that no material damage or diminution of reasonably foreseeable use could result in <br /> the event of mine subsidence within the permit and adjacent areas, and if the Division concurs with that <br /> conclusion, the application shall include a monitoring program designed to determine the accuracy of that <br /> conclusion, as described in Section 2.05.6(6)(c). <br /> (iii) If the description of worst possible subsidence consequences, prepared in accordance with Section <br /> . 2.05.6(6)(b)(i). determines the material damage or diminution of reasonably foreseeable use could result in the <br /> event of mine subsidence within the permit and adjacent areas, the application shall include additional <br /> information as required by either one of the following: <br /> (A) A subsidence survey, as described in Section 2.05.6(6)(e); <br /> (B) A subsidence control plan , as described in Section 2.05.6(6)(f). <br /> RESPONSE <br /> For the main mine entries, there is not expected to be any subsidence from instability of immediate roof spans or <br /> induced pillar loading. The analysis to corroborate this prediction is presented in Exhibit 7, Subsidence <br /> Predictions. Therefore, there will be no damage or diminution of structures or renewable resource lands above <br /> the main mine development entries. <br /> The analysis of worst case predictions for subsidence above production panels is presented in Exhibit 7, <br /> Subsidence Predictions. It must be emphasized that these worst case predictions are extremely conservative, <br /> and it would be expected that the actual subsidence will be well below these predictions <br /> 41 <br /> PR09 -08 2.05 - 181.11 04/29/09 <br />