2007-06-29_PERMIT FILE - C1981022A (2)

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Section - 2.1)5.3 In compliance with applicable MSHA regulations (30CFR 77.215), no burning or extraneous combustible material will be placed as refuse, any Fre that may occur in a refuse facility will be promptly extinguished in consultation with the MSHA District Office, and refuse placement will be suspended until any fire is completely extinguished (except non-combustible refuse materials that may be used to control or extinguish the fire). Maintenance practices include quarterly inspections by a Registered Professional Engineer or his qualified designate, certification on completion of each phase (new fill bench) of construction, clean-out and repair of drainage stmctures, and additional periodic inspections £or any evidence of instability or excessive erosion. Quarterly inspection reports note pile conditions, quantity and location of any refuse placed in or removed from the pile, any maintenance or repair activities completed, and the status of any final grading and reclamation activities. Any potentially hazardous conditions identified as a result of the inspections will be promptly reported to the DMG, and emergenry mitigation measures implemented as soon as reasonably feasible. The final design and constructed configuration of the coal refuse facilities includes catch benches and cross- drains to collect and route drainage off the fill to the designed perimeter ditches, outslopes that are 2H:]V or less, and a final bench configuration that is sloped to drain surface runoff to one or both sides of the fill to avoid directing drainage over the outslope of the fills. u I• East Yard Coal Refuse Facility -The C-Seam portal bench, where the East Yazd coal refuse facility is located, was constructed prior to ]977 and topsoil was not segregated and saved from this area during portal development. A three-foot layer of surface material was, however, removed from the portal bench prior to refuse placement and stored in accordance with Section 2.05.3(5) for future reclamation use. This material, which was stored both east and west of the coal refuse facility, has been identified for use as an Elk Creek yard soil borrow material. The soil material stored on the west side of the coal refuse facility was hauled to the East Yazd soil pile in 1993 in order to enlazge the existing refuse disposal area. This pile was subsequently consolidated with the Elk Creek soil stockpile during the mine expansion activities. The East Yard Coal Refuse Facility, as shown on the General Facilities Map, (Map 2.05-M1), is designed to contain approximately 60,000 cubic yards of refuse material. The coal refuse facility was nearing capacity in 1997 prompting OMI to proceed with identification, evaluation, design, and development of the new West Valley Coal Refuse Facility. In conjunction with construction of the Elk Creek coal stockpile pad, however, approximately 25,000 cubic yards of refuse was removed from the East Yard Coal Refuse Facility for use as fill. Removal of this material opened up additional available capacity for continued refuse placement in this area. Dependent on operating requirements and considerations, OMI may place coal mine refuse materials in either the East Yazd Coal Refuse Facility or the new West Valley Coal Refuse Factliry until the East Coal Refuse Facility reaches capacity. Once the East Coal Refuse Facility reaches capacity, all coal mine refuse disposal activities will shift to the West Valley area and the East pile will be reclaimed. During final reclamation, the pile surface will be graded to the approximate contours shown on the Facilities Postmining Topography Map, (Map 2.05-M6), and covered with four feet of non-toxic and non-combustible material. The 2.1 acre disposal site will require about 13,500 cubic yards of cover material. This covet material will come from excess cut material generated during reclamation of the Elk Creek coal handling, support, and ancillary facilities area. Slope stability analyses were performed for the East and West Valley, II West Coal Refuse Facilities. In general, the nature of the soil profile used in the initial slope stability model for the East pile consisted of refuse material overlt~ing shallow deposits of colluvium and man-made fill, with a bedrock surface consisting of inter-bedded sandstones, siltstones, and shales. A 4-foot thick layer of cover material was assumed to cover the refuse material. Material properties were obtained from a review of stability reports from three separate mines in the area. The material properties are summarized as follows: Mine Material ~ cohesion ag mma Red Canyon Mine Gob 28.5 200 78.8 North Thompson Greek Wash Plant 34.0 150 82.0 TR-43 2.05-47 Revised August 2003