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<br />Richard Mills <br />Page 3 <br />March 13, 1998 <br /> <br />Additional questions that need clarifications as a result of review of the last set of revised pages. <br />Numbering fol{ows the last adequacy numeration from the Division's February 27. 1998 letter: <br />71. a) On page 2.05-124(j), the text states "a visual observation in March of 1997 revealed that <br />the stream bed is sealed". How was that observation conducted? <br />b) Is Middle Creek still planned to be subsided by panel 6R as stated on page 2.05-124(j)? <br />c) The text on page 2.05-17Q)(6) concludes that the "extensive ditch system ...is not ~N`~ <br />conducive to irrigation." The Division does not agree with this statement. The presence <br />of an extensive irrigation system indicates that the AVF is conducive to irrigation. <br />d) Are the subsidence predictions for the powerline still applicable for the mine plan in <br />panels 7R-2R of the EMD? <br />e) Wha[ evidence is provided to support [he statement on page 2.05-126 that the flows in <br />Foidel Creek have returned to normal? What is the normal flow? What information was <br />used to determine the normal flow? e'~'`J ~ ~ •1-`~"'~°0 <br />f) On page 2.05-126(e) it is stated that the "ditch waters cropland" yet the permit states that <br />the pre-mining land-use is pastureland and rangeland (2.05-181). Which is correct? <br />g) Exhibit 7E-I does no[ contain subsidence prediction information for panel 17R. N ~~ <br />h) On page 2.05-184.3, the text incorrectly states that the Fish Creek AVF will be subsided <br />by 12R to 16R. This is incorrect if 17R is to be in this application. N M (~ <br />1) If cracks develop in the Ashley impoundment due to subsidence, this could cause excess <br />sedimentation due to embankment failure. The Ashley impoundment should have a <br />subsidence control plan, including subsidence monitoring. <br />j) Page 2.05- 181.3, bottom of the page text problem. <br />k) Text about water monitoring is mixed with railroad information on page 2.05-191.3. <br />Issues regarding undermining and monitoring the Fish Creek alluvial valley floor are the critical issues a[ <br />this point in the revision process. The Division is aware of the location of Twentymile Coal Company's <br />current extraction in panel Seven Right. We are also aware that approval by the Division must be granted <br />before Twentymile Coal Company may begin longwall mining in panel Six Right. 'iwentymile Coal <br />Company may want to assess whether the remaining adequacy issues can be appropriately responded to <br />within Twentymile Coal Company's time frame, or whether Twentymile Coal Company should address <br />the remaining adequacy issues of the Eastern Mining District, and remove all references to the Northern <br />Mining District from this revision? Please contact us regarding how Twentymile Coal Company wishes <br />to resolve these remaining concerns. <br />