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Based on the above information, the Division believes that there are two possible <br />approaches to solving the alignment problem for the North Tributary, East Pit Ditch. <br />First, the Division believes reconstructing the post-mining topography as originally <br />approved in this area is critical. The elevation difference of approximately 10 feet may <br />not be an issue in a large valley, where hundreds of feet of relief exists, but it is an issue <br />where only a few feet of relief defines the valley itself, like the lower North Tributary, <br />East Pit Ditch area. If the post-mining topography is reconstructed as approved, the <br />North Tributary can be constructed as designed. Since, this alternative is already part of <br />the approved permit, Colowyo could begin the repair work for this option immediately. <br />A second alternative would be to relocate the upper portion of the North Tributary, East <br />Pit Ditch from the outlet of proposed stock tank NTEP 1 (approximately station 9+00) to <br />the proposed intercept location with the Final East Pit Ditch shown on proposed Map 12 <br />to ose'statlon V+VV on roposeU 1V1Q 12) 11116 alternilLI wolAlU Q1so reiiulre a <br />minor reworking of the post-mining topography to ensure that this portion of the North <br />Tributary, East Pit Ditch is located in a topographically controlled valley. This alternative <br />would require the proposed changes to be included in Technical Revision 87. <br />The Division is concerned about this location because, in the long term, this valley leads <br />directly to State Highway 13. Any instability due to improper reconstruction could be <br />catastrophic. Fixing the post-mining topography in the area is necessary to properly <br />construct the lower portion of the North Tributary of the East Pit Ditch. The Division <br />requests that Colowyo review the on the ground topography and the approved post- <br />mining topography and determine the best course of action to redesign and reconstruct <br />the North Tributary, East Pit Ditch so that it is stable and topographically controlled. <br />Please contact me at (303)866-3567 X8145 if you have any questions or comments. <br />Sincerely, <br />James R. Stark <br />Environmental Protection Specialist <br />cc: Sandy Brown <br />Kurtis Blunt <br />Kent Gorham