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debris) slopes at the base of the sandstone cliffs to the northwest of <br />• the mine area. The colluvial slopes are comprised of sandstone and <br />shale debris of the 'Nilliams Fork Formation which has eroded off the <br />cliffs and slopes above. The natural slopes are then underlain by loose <br />spoil-like debris similar to the slopes at the top of the Swale. <br />Swale slopes were sampled at the steepest portion of the profiles <br />surveyed by CYCC across the Swale (see Appendix). colluvial slopes were <br />sampled at a 250 foot grid spacing within the boundaries of the <br />colluvial deposit. The grid spacing was adjusted to provide a large <br />number of samples (90 samples in this case). Slope gradient was <br />measured in the same manner as hillslope gradients on the mine. Samples <br />were taken from the map of existing topography at a scale of 1 inch <br />equals 500 feet. <br />• The average slope at the top of the Swale area does not differ <br />significantly from the average of colluvial slopes at a 95% level of <br />confidence. In fact, there are numerous samples of colluvial slope <br />gradients considerably steeper than gradients at the top of the Swale <br />(Fig. 2.7). Since the range of Swale slopes falls well within the range <br />of natural colluvial slopes, it is likely that the former will develop <br />surfaces similar to the colluvial slopes. In addition, the Swale slopes <br />have little area above contributing runoff to the steepest portions of <br />the slopes. <br />• <br />19 <br />