2010-12-15_REVISION - C1981019 - Laserfiche WebLink

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themselves to better equipment access for cleaning and repair and are likely to perform better over the extended liability period. Please consider the more traditional asymmetric terrace ditch design in accordance with Rule 4.14.2(2). Response: Rather than the ditches that were built for the 2009 East Pit and West Pit reclamation, a better example of these ditches are the contour ditches that were cut for the West Pit fill and Streeter fills. All terrace ditches, including those on the valley fills as well as those in the pit backfill areas above the valley fills have been sized to handle the 100-year, 24-hour storm. Please refer to revised Exhibit 7, Item 20, Part G, and revised Map 41A. We have revised the SEDCAD model for the terrace ditches to include an asymmetric design. Rule 4.05.6 - Sediment Ponds 13. Response Not Accepted. In Colowyo's response it is stated that the "typographical error is rendered moot..." because the pages with the error, Exh. 7-20C-7 through Exh. 7- 20C-78, are being replaced. No replacement pages were included in the response. These pages were not included on the response tracking sheet as being either removed or replaced, either. The original adequacy question still stands, as follows: The footer for the West Taylor Pond SEDCAD modeling states that the revision is TR-82. The correct revision number is TR-81. Please change the footer information for the West Taylor Pond SEDCAD modeling to TR-81 to reflect the correct revision number. Response: All SEDCAD printouts have been reviewed and resubmitted with an updated footer date and correct revision number at this time. This includes the modeling for the West Taylor Pond. 14. Response Partially Accepted. Colowyo has provided the additional introductory text for Exhibit 7, Item 20, Part C as requested. However, Colowyo has now presented two designs for the West Taylor Pond. It is not clear whether Colowyo is replacing the original West Taylor Pond model or not. The confusion may stem from the fact that, in response to question 13, Colowyo states that they were resubmitting pages Exh. 7-20C-7 through Exh. 7-20C-78, although no replacement pages were submitted (see also question 13 above). The referenced pages contain the West Taylor Pond model. Additionally, the West Taylor Pond model the Division currently has is based on the old post-mining topography and not the post-mining topography proposed with Technical Revision 81. Additionally, both pond design models use sumps or stock ponds as secondary sediment control measures for the worst-case disturbance in the watershed. Please provide the Division with a discussion of which West Taylor Pond design Colowyo wants to be included in the approved permit document and, as in question 13 above, please insure that the footnotes on the pages are correct. Please provide additional input or discussion related to the hydrologic design for the West Taylor Pond, including whether the sumping of water will be utilized or required as reclamation progresses in the watershed. Response: This response will be provided upon finalization of the hydrologic design. 15. Response Not Accepted. On Page Exh.7-20-7 Colowyo provides Table 4, which is a summary of the sediment ponds in the South Taylor area. Colowyo has updated the table, as requested, but there is still one problem with the table, specifically in the "sediment loading" section. Sediment loading into the pond and out of the pond appears to be inconsistent or inaccurate as compared to the approved SEDCAD modeling output for the West Taylor Pond. The information on "sediment loading" for Section 28 and Section 21