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The NOV states that side slopes of an unapproved valley in Area 31 <br /> are steeper than approved hillslope gradients. Therefore, slopes at the <br />Eckman Park Mine within the approved and existing topography are divided <br />into hillslopes and valley side-slopes. Hillslopes are generally <br />parallel to the dip of the sedimentary strata which control the slope of <br />the mine area. Hillslope gradients are approximately the same as the <br />overall slope of the mine area as well. Valley side-slopes are <br />immediately adjacent to drainage ways or stream channels and gradients <br />are higher than hillslopes. <br />Separate samples were taken from hillslope areas and from valley <br />side-slope areas. Hillslopes comprise the majority of the mine area and <br />they were sampled on a 500 foot grid throughout the mine areas. The <br />size of the grid was selected such that the sample size would be <br />• approximately 30 or more which is adequate for detecting a significance <br />of difference between samples. In this case sample size ranged from 200 <br />to 300 samples. Valley side-slopes consist of a narrow strip of <br />relatively steep slopes along the major ephemeral streams draining the <br />mine area. They were sampled every 500 feet along each channel at the <br />steepest zone on each side of the channel or drainage swale. Slope is <br />measured in percent by determining the perpendicular distance between <br />adjacent 25 foot contours. Slope data is tabulatetl in the Appendix. <br />Grid sampling of slopes throughout the mine area without <br />distinguishing between hillslopes and valley side slopes indicates no <br />significant difference between existing and approved slope gradients. <br />Significance was determined with a statistical t-test at a 95 percent <br /> <br />7 <br />