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ATTACHMENTI <br />CN VALUE FOR CALCULATION OF RUNOFF TO THE SEDIMENT POND <br />PLAN FOR DISPOSAL OF REFUSE FROM THE NORTHERN NO 1 (FFSEAM) <br />COAL MINE, RIO BLANCO COUNTY, COLORADO <br />In order to utilize the U.S. Soil Conservation Service methodology for <br />runoff calculation each of the projected land use categories has been placed into a <br />SCS classification. <br />Land Use SCS Classification CN <br />Roads Roads, dirt, Group C 87 <br />Top Soil Stockpile Fallow, Straight Row, Poor, Group C 91 <br />Stripped Areas Fallow, Straight Row, Poor, Group C 91 <br />Compacted Fill Roads, dirt, Group B 82 <br />Reclaimed Slopes Range, Good, Contoured, Group C 70 <br />Undisturbed Range, Good, Group C 74 <br />The worst case for runoff occurs when roads are Complete, topsoil is <br />stripped and stockpiled in advance of filling but no areas have been filled or <br />reclaimed. The case analyzed, therefore, has Phase I stripped, all roads <br />constructed, and the topsoil stockpile in place, with no fill or reclamation is <br />considered. <br />