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~~~ ~ ~ ~ ~ III III I II 1111111 III <br />STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1713 Sherman SL, Room 215 <br />Denver, Colorado 8003 <br />Phone: I]0}) 866Jib7 <br />FA%: 13031 8328106 <br />Forrest V. Luke <br />Trapper Mining, Inc. <br />P.O. BOX 187 <br />Craig, Colorado 81626 <br />Re: Trapper Mine (Permit No. C-81-010) <br />Technical Revision No. 77 <br />West Flume Culch Pond #1 <br />I~~~~ <br />DEPARTMENT OF <br />NATURAL <br />RESOURCE <br />Roy Romer <br />Governor <br />lames 5. Lochhcad <br />Executive Director <br />Mich lPl B. LOnF <br />Division Director <br />The Division has completed a review of the TR-79 application for the West Flume Gulch pond and <br />ditches. Based on our review we have the following questions and comments. <br />The eastern watershed boundary shown for J I B 1 S 1, S WS 1 appeazs to be in error, in that it <br />has been placed in the drainage bottom. It. would appear that approximately 8 acres to the east <br />of the boundary should be included. Please revise the boundary line or provide additional <br />information which supports Trapper's placement of the boundary. <br />2. Please provide additional information which demonstrates that the existing channels running <br />through the 31.1, 222, and 211 watersheds will remain stable with the increased flows that will <br />be directed to them under Trapper's proposal. <br />The diversions proposed are shown to intersect the main channel flows at nearly right angles. <br />What will Trapper do to ensure that flow makes the transition to the diversions, which are <br />roughly on the contour, rather than continuing to flow downgradient, bypassing the sediment <br />control system? <br />4. The ditch designs submitted are based on vegetated channels. Immediately following <br />construction and prior to establishment of vegetation, the channels will not be vegetated. <br />Please provide designs for stable channels in the interim. <br />The hydrologic model for the West Flume pond does not account for sediment storage in the <br />pond capacity determination. Please revise the model to include sediment storage . <br />6. After reclamation of the disturbed areas, before vegetation is reestablished, there will be <br />undisturbed areas between the reclaimed pit areas and the pond over which disturbed area <br />