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7. Reclamation cross-sections do not reflect an elevation change of the pit floor, though bedrock elevation will fall <br />from the up-gradient end to the down-gradient end. Though this mining practice is possible, it usually is not how <br />mining is conducted on a pit of this type. Please verify that the pit floor will be level, or revise the cross-sections <br />and map contours accordingly. <br />8. Please provide construction and sizing specifications for the sediment pond and the outlet for the sediment pond. <br />Please include calculations to verify the sizing is adequate to handle expected pit dewatering rates. <br />9. Please demonstrate that the sediment pond location is above the elevation of the 10 year-24 hour storm event. <br />10. Much of the dike design detail has been omitted from the technical revision, including compaction density for the <br />clay core, sizing for the boulder armoring, bank revetment detail, and an engineer certified stability demonstration to <br />a safety factor of 1.5. <br />11. Please include a commitment to complete construction of the dike prior to March 31, 2008, with engineer certified <br />as-built reports submitted to DRMS by April 15, 2008. <br />12. If the pit is to be dewatered and mined in a dry condition, please commit to leaving a minimum 1.5 foot layer of <br />gravel on the pit floor. The dewatering pump will need to be positioned, as much as possible, to allow groundwater <br />to flow over the shale bedrock to minimize oxidization of the shale and particularly the selenium. <br />13. I If the pit is to be dewatered and mined in a dry condition, please indicate what measures will be taken to minimize <br />hydrologic impacts to the riparian and wetlands area located between proposed Phase 3 and the Gunnison River. <br />Please ensure you send two copies of your response and that all revisions are appropriately accounted for in the reclamation <br />cost exhibit. <br />If you need additional information, please contact me at the Division of Reclamation, Mining and Safety, Grand Junction <br />Field Office, 101 South Third Street, Room 301, Grand Junction, Colorado 81501, telephone no. 970-243-6368. <br />Sincerely, <br />XA- <br />Steve S. Shuey <br />Environmental Protection Specialist