2010-12-15_REVISION - C1981019 - Laserfiche WebLink

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40. Map 18B - Pre-Mining Topography-Lower Wilson/South Taylor Area shows the currently approved mining limits for the South Taylor Pit, not the proposed mining limits. Please update Map 18B to reflect the proposed changes to the mining limits for the South Taylor Pit. Response: We believe this comment should be referring to Map 18A not 18B. Map 18A has been updated with this submittal. 41. Colowyo has provided Map 45 - South Taylor Fill, which shows the design of the West Taylor and East Taylor Fills, including cross-sections. With the proposed changes to the mining limits to the West of the South Taylor Pit, Colowyo is proposing to eliminate approximately 92 acres of the pit. In the originally approved mining and reclamation plan this area was going to be backfilled (obviously). With the revised plan, however, Colowyo is proposing to use a portion of this approximately 92 acres for an extension of the West Taylor Fill. This proposed extension of the West Taylor Fill runs from approximately 335000N to approximately 343000N and is shown on Map 41A but it is not shown on Map 45. Please include the portion of the West Taylor Fill that will run along the outside of the South Taylor Pit, on the west edge, from approximately 335000N to approximately 343000N on Map 45. Please adjust the scale of Map 45 as necessary to show the entire West Taylor Fill. Response: The permanent fill hatch has been added and the area of coverage for the plan view has been extended to show the entire fill area. 42. On Map 29A - Spoil Grading-South Taylor Area, Colowyo has changed the dates of reclamation of the faces of the West Taylor Fill from 2011-2012 to 2012-2013. Colowyo has similarly changed the dates of reclamation of the face of the East Taylor Fill from 2011-2012 to 2013-2014. Based on the South Taylor Pit mine plan, as shown on Map 23A, the South Taylor box-cut will be opened/completed in 2011, with the small cut to the west of the box- cut completed in 2012. Based on Colowyo's discussion of the West Taylor and East Taylor Fills, they are necessary for the development of the box-cut. If the box-cut is being completed in 2011 it follows that the permanent fills will be completed in that general timeframe as well. Additionally, it is a general practice to complete the face of the fill first and place the remaining material behind (upstream) the face following the completion of the face. Based on Colowyo's discussion of mining in the South Taylor Pit and a review of maps 23 and 29, it appears as though there is a discrepancy in the reclamation dates for the face of the West Taylor and East Taylor Fills. Please explain why Colowyo has proposed to change the dates of reclamation for the face of the West Taylor and East Taylor Fills. Please include a discussion of the reclamation of the fills in Section 4.09, including the timing of the reclamation and the reasoning for the timing. Response: This response will be provided upon finalization of the hydrologic design. 43. With the submittal of the responses to the Division's preliminary adequacy review letter for Technical Revision 81, Colowyo has proposed changes to the post-mining topography for the South Taylor area. Colowyo, for the most part, appears to be returning the South Taylor area to its approximate original contour. The Division has reviewed revised post- mining topography Maps 19 and 19A and has the following questions and comments. a. Colowyo has provided a new cross-section for the revised post-mining topography for the final cut of the Section 16 Pit. This cross-section is E-E' and is shown on Maps 19 and 20A. This cross-section shows the proposed post-mining topography for the final cut