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Permit Revision Adequacy <br />July 6, 2004 <br />Page 10 of 18 <br />earlier subsidence monitoring. Please add an explanation of how and where that was observed. <br />Were bedrock cracks observed to disappear beneath a cover of unconsolidated material? <br />75. Please describe the significance of the "angle of major influence" as defined on page 2.05-114 <br />and section 5.6 of Exhibit 60B and relate how that applies to the SOD situation at the West Elk <br />Mine. <br />76. On page 2.05-117, the first two number statements, please reiterate the predicted values for <br />clarity in the text. <br />77, On page 2.05-119, in the section titled "Potential Impact of Water..." does MCC have any <br />estimate of the probability of water effecting vertical displacements in the SOD based on <br />drilling or other observations? <br />78. The compilation of locations of steep slopes with potential for rockfalls on page 2.05-120 is <br />informative, but the Division requests that MCC provide a map showing these areas in relation <br />to proposed panel layout. Areas of greatest crack formation are predicted above barrier pillars, <br />for example, so the DMG believes that an evaluation of locations where the barrier pillars may <br />occur beneath cliff faces and other potentially sensitive features is necessary for prediction of <br />areas susceptible to rockfall. <br />79. The Division requests that MCC collect baseline information in the areas of low to moderate <br />rockfall potential, as noted on page 2.05-121, pazagraph 5. <br />80. Under the heading "Possible Subsidence Consequences," number 1 predicts that no cracks will <br />occur in the alluvium of Dry Fork or Lick Creek, implying the unconsolidated deposits there <br />aze greater than 10 feet thick. Please provide a reference to the observed thickness of the <br />alluvium in these areas. <br />81. On page 2.05-124, 2nd paragraph, does the author mean "Deep Creek" or Dry Fork? <br />82. On page 2.05-126, 2"d paragraph, the statement occurs "panels E through E9." Please add the <br />panel ntunber where appropriate. <br />83. On page 2.05-126, under "Preventative Measures," MCC will notify the Division if plans are <br />implemented of the type described which may effect the magnitude of subsidence. <br />84. MCC has determined that "structures" refer to buildings (page 2.05-93). The Division has a <br />long-established precedence of"structures" being defined as anything that is man-made. This <br />would include buildings, cabins, sheds, barns, stock ponds, roads, power lines, water lines, gas <br />or oil lines, water wells, vent fans, towers, swimming pools, tanks, reservoirs, etc. Map 67, <br />Man Made Structures in the Coal Lease Area, shows very little in terms of information of <br />value, especially for South of the Divide. Please submit a detailed map at an appropriate scale <br />of all structures in the current and proposed permit azea. (Rule 2.05.6(6)(a)(ii)(B)) <br />