Laserfiche WebLink
the original and approved channel configuration. Please inform the Division as to why <br />the channel gradient is a steeper configuration than what was originally approved. <br />10. Seneca revised the post mining topography of the C and D Pits. The new topography <br />proposed by Seneca is one long slope, with little variation in the terrain. The previously <br />approved topography had more variations in grade and contour. The variation in slope <br />and terrain will ultimately reduce erosion on the reclaimed slopes and provide a diverse <br />landscape for vegetation to establish. Seneca should reevaluate the proposed postmining <br />topography of the C and D Pits so that it has more variation in grade and contour, and <br />closer to the original contour. <br />11. Channel segment 005-E1 was revised by raising the elevation of the channel by roughly <br />80 vertical feet. This increased the slope of the channel in numerous segments. Seneca <br />did not inform the Division as to why the postmining topography in this area changed so <br />significantly. It appears that more spoil will be moved in the upper section of the pit, and <br />less in the bottom portion of the pit. In doing so, the upper section of the pit is steeper <br />than the lower section. It appears that the previously approved plan was more consistent <br />with the pre-mining topography and channel gradient. Seneca should inform the Division <br />as to why the postmining topography was revised for the D Pit. Seneca should also <br />reevaluate the proposed postmining channel grade for 005-E1 to closer approximate the <br />original channel. <br />12. In the permit pages, Seneca should also include a description of the granulaz filter layer or <br />geotextile filter fabric to be used in the reconstructed drainage channel segments prior to <br />placement of the rip-rap material. <br />As previously noted, the Division's decision due date is July 12, 1998. Please respond to these <br />concerns prior to this date. If you have any questions, please do not hesitate to call. <br />Sincerely, <br />~~~5.~~ <br />Erica S. Crosby <br />Environmental Protection Specialist <br />cc: Mike Boulay <br />David Berry <br />Larry Routten <br />c:\esc\seneca2w\9805 L 3 <br />