2007-07-30_GENERAL DOCUMENTS - C1981041

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1. Piezometric monitoring of the coal processing waste embankment; 2. Monitoring of side slopes to maintain a maximum slope angle of 2:1 between benches on CRDA-l, and 2.S:1 on CRDA-2; ' 3. Monitoring compaction of constructed lifts; and i+ 4. Quarterly inspection for stability and compliance with alproved plan by a registered professional engineer. I i; Geotechnical analyses included in the permit application show that CRDA-1 and CRDA-2 are stable at a minimum safety factor of 1.5. The following specific findings apply to the approved refuse disposal areas. ~^ 1. The disposal azea will be inspected on a regulaz basis by a qualified professional specialist under the direction ofthe professional engineer, experienced in construction ofsimilar earth and waste structures. ~ Inspection by this person has been approved by the Division as appropriate (4.10.2(1)) i Inspection shall occur quarterly and at critical construction periods. A copy of the inspection report will be retained at the mine office and a copy will'be forwarded to the Division. 2. An alternative subdrainage system for the coal mine waste aria has been approved. The Division finds that such an alternative will ensure the applicable static safety factor, stability of the fill, and protection of the surface and groundwater (4.10.3(5)). No underdrains will be constructed on Cameo Refuse Disposal Areas No. 2. The Roadside Refuse Disposal Area was also constructed without an underdrain. 3. The petmittee has demonstrated, based on physical and chemical imalyses ofrefuse material and cover soil, and vegetation field trials, that the revegetation requirements of 4. l 5 can be met with less than four feet of cover on the coal processing waste bank (4. I x).4(5)). This study which was conducted over a span of 10 years was finalized during the summer of 1993. A determination on the required cover depth was made by the Division pursuant to approval of Technical Revision 16, in January, 1994. For further relevant discussion, see Section B.III of this document. VII. Backfilline and Gradin Following removal of mine facilities, buildings, and asphalt, and sealing of underground mine openings, all areas affected by surface operations will be backfilled^and graded as necessary to stabilize slopes and promote successful revegetation. The anticipated final surface configuration for each affected surface area, as well as existing and proposed postmine cross-sections, are depicted in Exhibits 6C through 12C, and Exhibits 26, 27 and 28 of the permit application. I Original reclamation plans for the South Portals area had entailed retention ofexisting mine bench and highwall, but the plan had been revised to reflect elimination of the'',bench and highwall, and to approximate the general nature of the premining topography, prior to tYie 1993 permit renewal. As a component of the 1995 mid-term review, the Division requested additidnal detail on final reclamation configuration of the Roadside Refuse Disposal Area (RSRDA), and documentation of reclamation material balances for the entire South Portal azea, including the RSRDA. PR-02, approved~.in 1997, included a more detailed final reclamation jilan for the Roadside Refuse Disposal Area (RSRDA) and South Portals disturbance area. Documentation of material balances was also provided in PR-02, in 1997, and relevant postmine topographic maps and cross-sections were amended. Further refinements of the final reclamation plan for the South Portals and RSRDA, i i Permit Revision No. 3 ~ Permit No. C-1981-041 July 30, 2007 ~ Page 38