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2.2. Determination of Approximate Original Contour <br />• The NOV states that CYCC failed to approximate the, "...general <br />nature of the pre-mining topography". The approved post-mining <br />topography is assumed to represent approximate original contour for the <br />permit area. If the existing topography is not significantly different <br />from the approved topography, then AOC has been achieved. The question <br />then, is whether or not the existing topography approximates the <br />approved topography. <br />Three types of geomorphic analysis have been used to characterize <br />the existing and approved mine area topography. A grid sampling method <br />was used to sample hillslope gradient; hypsometric analysis was used to <br />determine the distribution of mass (i.e., spoil) within the mine area; <br />and measurements of drainage density in adjacent unmined areas were used <br />• to define a range of values for the area of the mine. <br />2.2.1. Slope Analysis <br />Oversteepened hillslopes are cited in the NOV in mine areas 9/10, <br />31, and 7. The MLR made field measurements of the gradient at specific <br />sites which were compared to map measurement of approved gradients. <br />They determined that the existing topography does not comply with ADC. <br />For this report a widespread sampling of topographic gradient <br />throughout the mined area was made to provide an objective comparison of <br />existing and approved topography. Statistical methods (Strahler, 1964) <br />were employed to calculate a quantitative measure of the significance of <br />difference in the topographic character of the existing and approved <br />• surfaces. <br />6 <br />