2007-03-06_GENERAL DOCUMENTS - C1994082

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this road and update the PAP to include an as-built profile to demonstrate compliance with Rule 4.03.3(3) and a landowner request in writing that the road be left open for further use in accordance with Rule 2.05.5(1)(b). Otherwise the road should be fully reclaimed. The possibility of changing the light-use road location and grade were discussed during the Phase I inspection due to the likelihood that portions of the road in its present configuration will not meet the vertical alignment requirements for light-use roads. Until such time that SCC provides appropriate demonstrations for permanent retention of the light-use road in the North Pit, the Division assumes that SCC will reclaim the road when it is no longer needed. Because this road has not been reclaimed and SCC has not requested it to be a permanent road, the entire length and width (including road cuts and embankments) of the light-use road will be excluded from Phase I bond release. A two-track road exists at the approximate location of the former haul road that led up to the south end of the north pit. This two-track road branches off of the light-use road and heads south up to the top of the southern end of the North Pit. The two-track road is not designed and constructed as a light-use road and is not identified as a light-use road in the PAP. According to SCC the road location has been graded and seeded. The two-track road blends well with the final grade of the surrounding topography and there are no road cuts or embankments. Therefore this two-track road will not be excluded from the Phase I bond release. However, when no longer needed, SCC should consider reseeding the two-track to ensure adequate cover and reduce the potential for erosion. Appropriate demonstrations in accordance with 4.03.3(3) and 2.05.5(1) (b) would be required for retention of this two-track road as a permanent light-use road. Drainase Reestablishment Comparison of the post-mining topography map (Exhibit 20-2) with USGS 7.5 minute Quadrangle Map of Mount Hams, Colorado indicates that two pre-mining drainages existed and were reconstructed in the appropriate locations. These are the locations of PM-9 and PM-10. Some differences were noted between original ground surface and post-mining topography at both PM-9 and PM-10 in that the final configuration of each of these channels was deeper than the original elevation of the pre-existing intermittent drainages. This elevation difference can be seen on Exhibit D Post-Mine Cross-Sections but is not considered a significant alteration of the approximate original contour since the drainages were restored in the approximately the same place as they existed prior to mining. Three permanent post-mine drainage channels (PM-9, PM-10, and PM-13) were inspected as part of this Phase I bond release to assess general design compliance. The lower Annand Draw drainage was not included in this bond release application and was not assessed as part of this inspection. Certified designs were approved for all post-mine drainage channels prior to this inspection and are provided in the PAP at Appendix 13-12.3. The permanent channels are designed to safely convey the peak discharge from the 10-year, 24-hour storm event in accordance with 4.05.3. Post-mine drainage channels PM-9, PM-10, and PM-13 located within this bond release request area were inspected for function with regazd to knickpoints, blending at disturbance boundaries and channel erosion. In addition to the certified designs, as-built drainage profiles (Exhibit E of the bond release application package) were also reviewed and evaluated in the field. The entire length of each drainage channel was walked and measurements were taken at the upper, mid and lower sections of each channel for comparison with design and as-built information. Channel gradients and bottom