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Item S. Which monitoring well or wells provide bedrock groundwater information for the Western <br />Mining District? <br />Response: Baseline and ongoing ground water monitoring address ground water conditions in both the <br />shallow alluvial deposits (Alluvial Wells 006A23 and AVF-13) and the Wadge complex (includes <br />water table conditions for the Wadge Coal Seam and associated overburden units - Ground water Well <br />91M006) <br />Item 6. Please add to the permit application a prediction of the worst possible consequences of <br />subsidence impacts to the springs that are located around the western perimeter of the Western <br />Mining District (shown on the recently submitted copy of Map I5A). Please include a table that is <br />similar to the partially completed one shown below, and include a description of the method and <br />assumptions used for predicting draw-downs from new Western District Mining in the table. <br />Spring Source <br />(Hydrostratigraphic Unit) Predicted Maximum Drawdown <br />of Potentiometric Surface of <br />Source at the Spring Location <br />Boeddeker Spring #1 <br />Boeddeker Spring #2 <br />Gertie Spring #1 <br />Livestock Spring #2 <br />Coyote Spring Trout Creek Sandstone <br />Perry Spring #1 <br />Perry Spring #2 <br />Perry Spring #3 <br />Perry Spring #4 <br />enry S ring #5 <br />Perry Spring #6 <br /> <br />Response: Area springs are generally not associated with bedrock aquifers, and are most commonly <br />associated with isolated perched ground water, where discontinuous depositional units of higher <br />permeability are underlain by lower permeability beds (refer to the discussion of ground water <br />hydrology in Section 2.04.7 of the PAP). Given these considerations, springs are generally not affected <br />by underground mining except where they fall within potential subsidence zones, as defined by the <br />projected angle-of-draw. All of the springs and seeps identified in the table above, fall well outside the <br />projected angle-of-draw for the WMD, and are therefore not expected to be impacted by the proposed <br />mining operations and any associated subsidence. In addition, these springs lie on the margins of the <br />Twentymile Park structural basin and recharge areas are upgradient of both the springs and the planned <br />mining activities, so it is unlikely that recharge will be impacted. In the unlikely event that mining- <br />related impacts do occur, TCC has sufficient water-rights under its approved Augmentation Plan to <br />address those impacts. <br />Item 7 The Table of Contents (TOC) and numbering of new appendices duplicate existing approved <br />exhibit names TOC page i names Exhibit 6R as "Western Mining District (PR09-08) Cultural <br />Resource Information (Confidential Appendix)." This exhibit number, 6R, has previously been <br />approved as "18-Left Vent Shaft Installation-Cultural Resource Information (Confidential <br />Appendix) " Please give the Western Mining District Cultural Resource Information a unique <br />exhibit name.