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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 />C O L O RA D O <br />D I V I S I O N o f <br />Denver, Colorado 80203 <br />RECLAMATION <br />Phone: (303) 866 -3567 <br />M IN I NIN G <br />N <br />FAX: (303) 832 -8106 <br />SAFETY <br />August 8, 2013 <br />John W. Hickenlooper <br />Governor <br />Roy Karo <br />Seneca Coal Company <br />Mike King <br />P.O. Box 670 <br />Executive Director <br />Hayden, Colorado 81639 <br />Loretta Pineda <br />Director <br />RE: Seneca II -W Mine; C- 1982 -057; TR80 <br />Adequacy Review No. 1 <br />Dear Mr. Karo, <br />The Colorado Division of Reclamation, Mining and Safety received Technical Revision No. 80 (TR80) on July <br />12, 2013. The Division deemed the application complete on July 22, 2013. There are several items that will <br />need to be addressed prior to the approval of the technical revision: <br />1. SCC has proposed the addition of two culverts (PM -3A and HRC -J3A) as supplemental culverts to assist <br />in conveying design flows, and has not included design information for those culverts. The omission of <br />design information is appropriate in this case. However, if at some future date SCC revises the drainage <br />plans to rely on these culverts, design information would be required. <br />2. SCC provided a SEDCAD Utility Run for Culvert PM -19, using a base flow value of 0.31 cfs. It is not <br />clear how SCC arrived at this base flow value. The approved PM -2 channel design assumes a flow of <br />24.10 cfs in a 10 year -24 hour precipitation event. The Division understands that the purpose of this <br />culvert is to provide a low water crossing for equipment but needs a better understanding of the design <br />premise to determine if the culvert will convey the typical base flow without siltation/clogging, which <br />would result in an impediment to conveyance of the design flow in the ditch. Please provide additional <br />information on how SCC determined the base flow value to be 0.31 cfs. <br />3. Revised tables 13 -5 and 13 -7 -1 have been updated to include the three proposed culverts. Comparing the <br />proposed tables to the currently approved versions, it appears that SCC also revised the table to delete the <br />"removed" status for culverts HRC -Y3, K -1, and PM -16. Please verify whether these revisions were <br />intentional, and if the culverts have been removed, revise Exhibits 13 -2 and 20 -2 to reflect the current <br />status of the culverts. <br />4. Revised Exhibits 13 -2 and 20 -2 were reviewed to determine if the culverts listed on revised tables 13 -5 <br />and 13 -7 -1 are depicted on these maps. Several inconsistencies were identified. <br />a. Culvert HRC -A5 is depicted on both map exhibits but the revised tables indicates this culvert was <br />removed. <br />b. Culvert HRC -I1 is listed as an existing culvert on revised tables 13 -5 and 13 -7 -1, however this <br />culvert does not appear to be depicted on the revised map exhibits. <br />c. Culvert HRC -J2A is depicted on both revised maps but it is not listed on the revised tables. <br />Please verify the existence of these culverts and revise the maps and/or the tables accordingly. <br />Office of Office of <br />Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines <br />