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General Grading Requirements <br />Final Graded Slopes: Post - mining slopes will not be uniform but will approximate the general <br />nature of the pre- mining topography. All highwalls will be eliminated and graded to a 5:1 slope <br />or flatter. <br />Terraces: Terracing in the final reclamation is not proposed at the NHN Mine. <br />Small Depressions: Small depressions are not proposed at the NHN Mine. <br />Steep Slopes: NHN Mine does not have steep slopes as defined in the regulations. <br />Final Grading: Final grading and preparation of the backfilled material before placement of <br />topsoil material will be completed along the contour to minimize subsequent erosion and <br />instability. If such grading is hazardous to equipment operators, then grading will be done in a <br />direction other than generally parallel to the contour. <br />Final Pit Backfilling: In order to eliminate any final highwalls and to achieve the approximate <br />original landform, some highwall material will be pushed or dozed into the mined area. Map <br />2.05.4 -2 shows typical cross sections of the fill material placed into the mined pits. Material <br />above the final highwall may be blasted or ripped and then graded to blend into the surrounding <br />topography. <br />Thin and Thick Overburden: The NHN Mine permit area does not meet the requirements of <br />either the thick or thin overburden as shown by the following calculations: <br />96.00' maximum stripping depth <br />55.91' average overburden <br />9.60' Max. Combined Upper and Lower Dakota <br />Section 2.05.4(2)(c) Page 2 February 2012 <br />