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~' <br /> <br />MLRD LETTER OF MARCH 5, 1967~I~'-,~' ~f~' ~~~. <br />COMMENTS & RESPOh;SES <br />lil'R 1~ 1987 <br />MLRD COMhIENT: <br />Area 41 <br />"J:Iiv tLi ~.+irv <br />r~tc>~f~,~riorv olvisiorv <br />We find that the plan proposed in the revision for Area 41 does not <br />represent approximate original contour. The Area 41 plan includes <br />significantly oversteepened slopes at the base of the spoils and a cross <br />slope diversion ditch above the steep slope at the base of the spoils and a <br />cross slope diversion ditch above the steep slope segment as a permanent <br />structure. This plan does not comply with the provisions of Rule 4.14.2 <br />which specify that "...final graded slopes shall not exceed in grade either <br />the approximate pre-mining slopes or any lesser slopes approved by the <br />Division" and "final graded slopes need not be uniform but shall approximate <br />the general nature of the pre-mining topography identified in 2.10.3(1)(j)". <br />• <br />Further, the plan depends upon structural controls which are not appropriate <br />for the post-mining land use. Consideration needs to be given to reduced <br />slope gradients as the appropriate means of stabilizing the area. The <br />pre-mining topography map depicts an ephemeral tributary of the South Fork <br />of Foidel Greek with a gradient of approximately 20°6 in the area in <br />question. By contrast, the proposed plan would result in a slope gradient <br />of over 40°0, and no attempt would be made to restore an ephemeral channel <br />which would approximate the general nature of the pre-mining topography. <br />The proposed diversion ditch which would intercept surface drainage above <br />the steep slope segment is not an appropriate substitute for a well <br />designed, naturally appearing ephemeral drainage with a channel gradient of <br />20b or less. <br />RESPONSE: <br />As stated in the report prepared by Water Engineering and Technology, <br />• Inc., and further supported by legislative intent, the overall <br />operation has achieved the AOC requirements. CYCC is of the opinion <br />that AOC requirements apply to the entire mine area and not isolated <br />areas within the mine area. <br />