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III ~Il~ll~ll~u~nt~ <br />y 5T?ATE O~ L:ULURADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Depanmenr of Natural Resources <br />131 7 Sherman Sr.. Room 215 <br />Denver. Colorado 80203 <br />Phone: 1303)066-356: <br />FAX: 13031 8328106 <br />April 9, 2001 <br />Mr.Tony Adkins <br />Mine Engineer <br />Westem Fuels-Colorado <br />P.O. box 628 <br />Nucla, CO 81424 <br />~~ <br />DIVISION O F i <br />MINERALS <br />GEOLOGY <br />RECLAMATION <br />MINING•SAFETY <br />Bill Owens <br />Governor <br />Greg E Walther <br />Execuuve Dvenor <br />Michael 8. Lonq <br />Dimsion Dvenor <br />Re: New Horizon Mine, Permit C-81-008 <br />Update of Probable Hydrologic Consequences (PHC) section of permit application <br />Dear Mr. Adkins: <br />At the request of the Division, Westem Fuels began the process of updating the PHC section of New <br />Horizon's permit during the review of Permit Revision PR-O5. The update may be submitted in a <br />Technical Revision to the permit. The last cortespondence regarding the update was Westem Fuels' letter <br />to the Division of February 18, 2000 (see attached copy). The Division has the following comments on <br />your responses in that letter. <br />The Division considers the following responses to be adequate as submitted, and has no further comment <br />on them: 1, 2, 3a, 3b, 3d, 4, 5, 6, 9,12, 13 and J4. <br />The Division has the following cotrunents on the other responses. <br />Comment 3e. After the projected TDS level is established for comment 7, please update calculations in <br />the permit of the projected TDS loading to Calamity Draw, Tuttle Draw, and the San Miguel River that <br />can be expected from: <br />a) Spoil Spring #1 (New Horizon 1 Mine), and <br />b) the spring predicted in your responses 2 and 3b to form at the New Horizon 2 Mine <br />near Northing 602,530, Easting 1,112,350 (NWSW Sec. 36- 47N-16W). <br />Comment 3c and 7. Your response draws an analogy between the water quality trend observed at Spoil <br />Spring #l (New Horizon #I Mine) and the projected water quality trend at the spoil spring expected to <br />form at New Horizon #2 Mine. The Division believes the analogy is invalid for the following three <br />reasons. <br />a) The drop in TDS and sulfate values shown in your graph (your Attachment 2) is probably <br />due to dilution, rather than depletion of minerals in the spoil mass. The sample data in the <br />graph in your Attachment 2 were collected at a wide range of discharge volumes. The Division's <br />attached Figure I shows that at least 68% of the recent decline in sulfate concentration at Spoil <br />Spring #1 can be attributed to the spring's recent increasing discharge rate. This dilutional effect <br />would mask any trend in sulfate or TDS concentration that is caused by depletion of minerals in <br />