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COLORADO <br />Division of Reclamation, <br />Mining and Safety <br />Department of Natural Resources <br />29 April 2015 <br />To: Brock Bowles <br />From: Robin Reilley <br />Re: RE: New Horizon Mine (C1981 -008) <br />Technical Revision TR 67 <br />Dear Brock, <br />I was asked to review the New Horizon Mine Technical Revision 97 for a culvert change requested by the <br />County at Pond 008, the restoration of the BB Road west of 27.00 Road and the update of the as built <br />drawing for Pond 008. <br />Rules: 2.05.3- (4), Ponds Impondments and other treatment facilities and diversions <br />The Proposed as -built Map 2.053(3) -4 -2 shows a storage capacity of 0.063 ac /ft at elevation <br />5647.0 ft (bottom of pond) while the current SEDCAD in the permit of March 2006 shows <br />0.00 ac /ft at the same elevation. Please clarify the proper storage capacity at the 5647.0 <br />ft elevation for Pond 008. <br />RESOLVED <br />2. Regarding the update of the as -built drawing of Pond 008, Map 2.05.3(3) -4 -2 shows the <br />drainage are to be 102.9 acres but the SEDCAD was run using 110.436 accres (attachments <br />2.05.3(3) -4 -2 and 2.05.3(3) -4 -4). Please clarify the proper acreage for the drainage basin <br />for Pond 008. <br />RESOLVED <br />3. In Attachments 2.05.3(3) -4 -2) and 2.05.3(3) -4 -4 of the approved permit, the units are <br />inconsistent across the two analysis. The inconsistencies are in total area (AC vs SQFT), <br />gross erosion, total yield, run off volume, sediment volume and total volume. The division <br />cannot complete its review of the culvert change for Pond 008 with the currently approved <br />SEDCAD runs. Please make units consistent across the input and output in attachments <br />2.05.3(3) -4 -2) and 2.05.3(3) -4 -4 and resubmit the SEDCAD runs ofd the Pond Volume <br />Calculations for both the 10 and 25 year 24 hour events. <br />RESOLVED <br />Sincerely, <br />Robin Reilley, GISP <br />Environmental Protection Specialist <br />of co Z01, <br />1313 Sherman Street, Room 215, Denver, CO 80203 P 303.866.3567 F 303.832.8106 http: / /mining.state.co.us I ryes o`N <br />John W. Hickenlooper, Governor I Mike King, Executive Director I Virginia Brannon, Director <br />* J R7_6 <br />