2010-07-16_REVISION - C1981019 - Laserfiche WebLink

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32. Response Accepted. The reference to Appendix B has been removed from Figure 4 (now Figure 13) as requested. 33. Response Accepted. Adjustments have been made to the lower boundary for clay and additional rational on Page 3 of Addendum 3 of the Shannon Wilson report has been added as requested. General Comments 34. Response Partially Accepted. While Colowyo has made changes to the post-mining topography, permanent fills and temporary fills that appear to have addressed the Division's concerns regarding Colowyo's variance from AOC and excess spoil, there are still numerous technical adequacy issues that must be addressed before the Division will be able to propose a decision. New Adequacy Questions Based on Colowyo's 1 June 2010 Responses 35. Colowyo has provided Map 41 - Watershed Boundaries for Hydrologic Modeling-South Taylor Area, which shows the post-mining drainage channels for the South Taylor Pit area. On this map several minor tributaries are shown on the east edge of the revised South Taylor Pit. These tributaries are labeled TRIB. A through TRIB. I. These tributaries are meant to convey flow from the reclaimed surface to the Section 28 and Section 21 Ponds. Several of these tributaries do not appear to be topographically controlled. That is, they appear to have been placed in their original configuration or location, at the intercept point with the undisturbed drainage, with no regard as to whether there is really a drainage in the reclaimed topography above the undisturbed drainage location. Because the reconstructed post-mining topography does not create a drainage in these tributary locations, it is unclear how water will be conveyed into the natural, undisturbed drainage and into the appropriate sediment pond. The tributaries that do not appear to be topographically controlled are B, D, E, G and H. Please review TRIB. B, D, E, G and H to determine if their locations are appropriate for a final drainage channel. Please either change the proposed drainage location(s), the post- mining topography in these locations or give a detailed explanation describing how these tributaries will perform as designed. Please update all SEDCAD modeling and maps as necessary. 36. Colowyo has removed the Section 28 Collector Ditch from Map 41A. , Another missing item is the Section 16 Pond Ditch (and extension), which is critical for sediment control for the east side of the South Taylor Pit and the X-Pod area. Please return the Section 28 Collector Ditch to Map 41A and add the Section 16 Pond Ditch (and extension) to Map 41A. 37. Currently approved Map 41 and proposed Map 41 A show the watershed boundaries for hydrologic monitoring for the South Area and the South Taylor Area, respectively. These maps also show the permanent, post-mining drainage channel locations. There are several sections in Township 3 North that are duplicated on both maps. These sections