2017-02-03_REVISION - C1980004 (6)

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IX. COAL MINE WASTE — RULE 4.11 Coal mine waste in the form of coal fines scraped up from the coal yard area, high ash coal that cannot be blended and shipped, and coaly sediment from the cleanout of ditches, sediment traps and the sediment pond will be disposed of in an approved permanent coal mine waste disposal site in the adjacent Munger Canyon permit area (Permit No. C-81- 020). The Munger Canyon Mine is also operated by CAM. Detailed construction and reclamation designs for the coal waste disposal site were approved by the Division pursuant to Technical Revision 14 (TR -14) to the Munger Canyon Mine permit, in November 2002. Specific findings pursuant to Rule 4.10.1(2), allowing for disposal of waste material from sources outside of the permit area are included in the approved permit for the Munger Canyon Mine. Development work was completed in the fall of 2004 and initial waste disposal at the Munger Canyon disposal site occurred in late November 2004. Several small temporary coal waste stockpiles are approved in the vicinity of the product coal stockpile at McClave. There is also an approved sediment drying area stockpile near the McClave sediment pond. Material from these stockpile locations will be periodically hauled to the permanent disposal site in the Munger Canyon permit area. The McClane Canyon application also notes that rock slope material will be disposed of in areas of the mine that are no longer actively producing coal, as authorized by MSHA. As noted on page 7 of the Division's February 19, 1999 mid-term review document, disposal within the mine is limited to rock generated during the normal course of mining operations, in accordance with standard industry practice, and in compliance with applicable MSHA requirements. Return of coal mine waste from the surface to underground workings is not approved. Non -coal waste (e.g. trash and non -coal combustibles) are stored in a dumpster on site and hauled off for permanent disposal by a commercial trash company. There is no permanent disposal of non -coal waste material on-site. X. BACKFILLING AND GRADING — RULE 4.14 Information relevant to backfilling and grading is presented in Sections 3.0 and 3.3-1, of the application. Postmining contour maps and cross sections are included as Figures 3.1-1 and 3.1-2, premine topography is depicted on Figure 3.1-3, and a stability analysis section is depicted on Figure 3.1-4. The lower portion of the affected area will be returned to approximate original contour (AOC), but the mine bench area will not be returned to AOC. The operator submitted information in the original permit application, and in association with the 1985 permit renewal demonstrating that the mine bench area qualified as steep slope mining pursuant to 2.06 and 4.27. The Division approved a limited variance to the AOC requirements of 4.14 and 4.27.3, to allow for backfilled slopes of lesser steepness, which would meet applicable stability criteria and support the approved post -mine land use. Average slopes in the mine bench area prior to mining ranged from 80% to 85%, whereas the backfilled valley side slopes will range from approximately 40% to 60%. The post -mine topographic configuration will be similar to premine, and stable drainage channels will be reconstructed in their approximate original locations. The highwall will be completely backfilled, with 30