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STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1313 Sherman St., Room 215 <br />Denver, Colorado 80203 <br />Phone: (303) 866-3567 <br />FAX: (303~tJ~~t~03 <br />Mr. Henry Bazbe <br />Mountain Coal Company LLC <br />P.O. Box 591 <br />Somerset CO 81434 <br />Re: West Elk MR-296 Adequacy Letter <br />Deaz Mr. Barbe: <br />The Division has completed review of the Sedcad designs and nomography for MR-296. The submittal <br />uses peak flows that aze presented in Table 44E, found in Exhibit 66 of Volume 8A-1. There aze several <br />comments: <br />1. Table 44E, in Volume 8A-1, needs to be revised to show that the diameter of culvert C2R-4 is 30 <br />inches, not 36 inches. <br />2. Table 44E in Volume 8A-1 shows that culvert C2-13 is a 24 inch diameter halfpipe and a 24 inch <br />diameter full pipe. However, the designs show that a 24 inch diameter full culvert is needed. The <br />24 inch diameter half pipe would appeaz to be insufficient. <br />3. The nomograph for culvert C2-SA uses a peak flow of 18.3 cfs, instead of the correct value of <br />15.62 cfs. However, this discrepancy only decreases the headwater depth from 1,1 to about 0.91. <br />The culvert size still passes the design flow. I don't think it is worth revising the nomograph. <br />4. As with all culverts that use a headwater factor in their hydrology designs, the height above the <br />top of the culvert inlet that water can rise up to should be checked in the field to slake sure it is <br />what the design says it is. <br />If you have any questions, please feel free to call me or Joe Dudash at the Division. <br />erely, <br />0 <br />im Burnell <br />Environmental Protection Specialist <br />DIVISION O F <br />MINERALS <br />GEOLOGY <br />RECLAMATION <br />MINING•sAFETY <br />Bill Owens <br />Governor <br />Greg E. Walther <br />Executive Director <br />Ronald W. Cattany <br />Division Director <br />cc: J. Dudash, Sandy Brown <br />