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STATE OF COLORADO <br />DIVISION OF RECLAMATION, MINING AND SAFETY <br />Department of Natural Resources <br />1313 Sherman St., Room 215 <br />Denver, Colorado 80203 C O L O R A D O <br />D IV IS I ON OF <br />Phone: (303) 866-3567 RECLAMATION <br />FAX: (303) 832-8106 Interoffice Memo M I N I N G <br />- tSt- <br />SAF E T Y <br />To: Jim Stark <br />From: Kent Gorham <br />CC: Sandy Brown <br />Date: January 27, 2011 <br />RE: Adequacy review #3, TR-81, Colowyo Mine, C-81-019 <br />I have completed my review of the materials received from Colowyo on January 6, 2011 <br />addressing the Divisions second adequacy letter for Technical Revision No. 81 (TR-81) for <br />the Colowyo Mine, #C-81-019. My comments are ordered as per the question numbers of <br />that letter. Any remaining concerns are highlighted in bold for the specific question. <br />12. Response partially accepted. Please add the flow direction arrows the terrace <br />benches on Map 41 a as per the map legend. <br />13. Response accepted. Footer changes were noted. <br />14. Response accepted. West Taylor pond design is explained. <br />15. Response accepted. Table 4 and sediment loading is corrected. <br />35. Response not accepted. The Division did not ask that small "V's" be added to each <br />contour line where each tributary crosses a contour line. The Division's issue is that <br />Tributary ditches B, D, E, G, and H do not appear to be topographically controlled by <br />the post-mining topography. Further discussion of each problematic tributary is proved <br />as follows. <br />o Tributary ditch B empties onto the undisturbed area on the side of a ridge and <br />was not present in the pre-mining topography. <br />o Tributary D appears to need moved to the west and the 8050 foot PMT contour <br />should loop back further into the disturbed area. <br />o Tributary E empties into no apparent existing channel and appears to be <br />unnecessary as no drainage was present in the pre-mining topography. <br />o Tributary G appears to be mis-aligned based on the post-mining topography <br />and/or may need an additional branch to the west. <br />Office of Office of <br />Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines