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2.05.6(6) <br />Spring 21 was undermined by the B -Seam during August 2011. The <br />overburden at this location is 475 feet. There was no apparent damage to <br />the spring based on monitoring results since the spring was undermined. <br />A report presented in Volume IIIA, Exhibit 17 provides a prediction of surface <br />deformation resulting from longwall mining in the Dove Gulch Area. Trough <br />type subsidence in predicted over Dove Gulch. The predicted maximum <br />subsidence near the center of the panels is 9 feet. Predicted tensile strains <br />reach levels that can cause surface fractures. Most surface fractures will <br />occur on the eastern side of the panels where shallow overburden is present. <br />No mining occurred under the springs and ponds in Dove Gulch. <br />Federal Lease 37210 stipulation 'g' states in part: "Coal extraction will be <br />limited in buffer zones established along East Roatcap Creek and Stevens <br />Gulch where the overburden is 600 feet or less ". Therefore, permanent <br />protective pillars are not required under Stevens Gulch since the overburden <br />at the end of the B10 and B -11 panels is approximately 1500 feet. A limited <br />extraction zone will not be established along the northern section of Stevens <br />Gulch as it passes through Sections 1 and 12. <br />The 1 West Mains go under Terror Creek and the Curecanti -Rifle 230/345 - <br />KV transmission line and support towers as shown on Map 14 -B. A limited <br />extraction zone has been established where the mains cross under Terror <br />Creek and the transmission line. A report prepared by Hamid Maleki titled <br />"Overburden Stability Evaluation at Terror Creek Crossing" demonstrates the <br />support pillars in the 1 West Mains under Terror Creek will have a minimum <br />factor of safety of 2.5. The report is presented in Volume IIIA, Tab 16. <br />A limited extraction zone will be established under WAPA transmission line <br />towers. <br />(f)(iii) A narrative of the detailed description of the measures to be taken to prevent <br />subsidence from causing material damage or lessening the value or <br />reasonably foreseeable use of the surface follows: <br />PR -14 2.05-162- 03/14 <br />