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VII. Coal Mine Waste <br />A. The Division has approved plans for use, construction and maintenance of a coal mine <br />waste disposal area. Details concerning the construction ofthe waste pile can be found <br />in Appendix 7-(1) of the permit application. The coal mine waste will be underground <br />mine waste rock extracted over the life of the King Coal and King II Mines. The <br />material is composed of dense, medium grained sandstone with occasional shale and <br />cazbonaceous shale partings. <br />The valley fill waste pile is located east of the King Coal Mine entrance, beginning just <br />east of the shop building and extending up the east side drainage approximately 900 <br />feet. A limit equilibrium static analysis was performed using effective stresses to <br />assure long term stability of the bank. A relatively flat 2.Sh :lv slope is used for the <br />face of the waste pile. This analysis provided a range of factors of safety between 1.85 <br />and 2.74, well above the required 1.5. An intercept channel was constructed at the top <br />of the bank to divert flow originating above it away from the bank and into the east <br />side drainage. Similazly, a channel was constructed at the bottom of the waste bank to <br />intercept runoff from the pile. An under drain system was constructed beneath fill and <br />drains into the east side drainage (4.04.8(3)). <br />B. The applicant has demonstrated that disposal of such materials will not adversely affect <br />water quality or flow, vegetation, public health, or stability of the disposal area based <br />on hydrologic, geotechnical, physical, and chemical analyses. The waste pile designs <br />exceed the minimum safety factor of 1.5. The new designs for the expanded waste pile <br />were approved February 9, 1998. <br />C. The disposal area will be inspected on a regulaz basis by a qualified professional <br />specialist under the direction of a professional engineer, experienced in construction <br />of similar earth and waste structures. Inspection by this person has been approved by <br />the Division as appropriate (4.10.2(1)). <br />VIII. Backfilling and Grading <br />Backfilling and grading of disturbed areas is described in Section 2.05.4 of the permit <br />application. Maps C-7 and King II-010 show proposed post-mining contours. <br />At the end of the King Coal Mine's life, NKC proposes to backfill the disturbed bench <br />azeas of this mine to a stable configuration that blends with the surrounding topography. <br />Based on information provided by NKC, no pre-mining contour maps of the King Coal <br />Mine exist due to the length of time the mine has been in operation (>50 yeazs). Proposed <br />backfilling of the King Coal Mine involves reducing all mine bench highwalls and the <br />bench outslope crest to approximately 1.5 h:lv and in most azeas to 2.Sh :lv or less to <br />blend in with surrounding azeas. The portal area of the King II Mine and all other disturbed <br />areas on this mine will be reclaimed to approximate original contour. <br />20 <br />