Laserfiche WebLink
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) 832-8106 <br />DATE: June 6, 2003 <br />DIVISION OF <br />MINERALS <br />GEOLOGY <br />RECLAMATION <br />MINING•SAFETY <br />TO: Jim Burnell Bill Owens <br /> Governor <br /> <br />~ Greg E Watcher <br />FROM: Joe Dudash Executive Director <br /> Ronald W. Cattany <br />RE: West Elk Min , rmit No. C-80-007, Mountain Coal Company Division Direcor <br /> Minor Revision No. 296, Sedcad Designs and Nomographs for Culverts <br />I have finished my review of the operator's responses to our adequacy review letter for MR-296, <br />The operator's responses are acceptable to the Division. <br />Table 44E, in Volume 8A-1, needs to be revised to show that the diameter of culvert C2R- <br />4 is 30 inches, not 36 inches. <br />The Division has no further concerns. This table was revised previously in MR-294. <br />2. Table 44E in Volume 8A-1 shows that culvert C2-13 is a 24 inch diameter halfpipe and a <br />24 inch diameter full pipe. However, the designs show that a 24 inch diameter full culvert <br />is needed. The 24 inch diameter halfpipe would appear to be insufficient. <br />The Division has no further concerns. The operator stated that this half pipe design was <br />previously approved in TR-86. There is sufficient capacity because the half culvert is set <br />at the bottom of a larger-sized ditch. <br />3. The nomograph for culvert C2-SA uses a peak flow of 18.3 cfs, instead of the correct <br />value of ]5.62 cfs. However, this discrepancy only decreases the headwater depth from <br />1.1 to about 0.97. The culvert size still passes the design flow. I don't think it is worth <br />revising the nomograph. <br />The Division has no further concerns. The operator noted the comment. <br />4. As with all culverts that use a headwater factor in their hydrology designs, the height <br />above the top of the culvert inlet that water can rise up to should be checked in the field <br />to make sure it is what the design says it is. <br />The Division has no further concerns. The operator noted the comment. <br />cc: Sandy Brown <br />c: /word/westelk/mr296memo2 <br />