1997-05-27_GENERAL DOCUMENTS - C1981017

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in the permit files delineates the portion of the refuse pile which was placed prior to August 3, 1977. Field observations tend to indicate that the northern portion of the Old refuse Pile have not been affected by mining operations since 1977. Refuse Pile Characteristics The area of the Old Refuse Pile subject to this proposal lies immediately above and adjacent to the south bank of Coal Creek just downstream of the confluence with Dutch Creek. The toe of the pile at the project area is located about twenty feet south of Coal Creek, and about twenty five feet higher than the channel. Cross sections measured from existing maps indicate that slopes at the project area vary from 1.5H:1V to 1.75H: 1V (300 to 340) . It is assumed that the pile was constructed without being compacted as lifts were developed. It is also assumed, based upon the number and locations of seeps which present themselves on the face of the pile, that lifts were not necessarily constructed in a manner which promoted drainage of the refuse at the time of disposal. Surficial slumps and small rotational-like failures have been observed on the north and east faces of the pile, indicating a propensity toward failure. Project Specifications The project area is divided into two areas: an eastern and a western project area. The western area slopes will be reduced to enhance stability. At the eastern area, slopes will be stabilized through tree planting. The western project area slopes will be laid back to a more gentle configuration. Because the Old Refuse Pile expands both vertically and to the south from the southern margin of this area, there is a limit to the degree of slope relaxation which can economically be achieved. Therefore, it is proposed that an average slope gradient of 2 . 25H:1V to 2.5H:1V (220 to 240) be attained. Preliminarily, it is estimated that 37,000 cubic yards of material will be moved from the face of the pile to achieve the desired slope configuration. The excavated material will be hauled about 1,500 feet over level terrain to the disposal site. After excavation is complete, approximately 3 ,900 cubic yards of topsoil Substitute, if available, will be end dumped over the excavated slope to an eight inch depth. The project area will then be fertilized, seeded and mulched. Seedling trees will be planted at a rate of 400 trees per acre to complete the project. In order to facilitate revegetation success and minimize erosion, a drainage control channel will be excavated at the edge of the Old Refuse Pile access road which crosses the southern margin of the project area. The ditch would simply mimic an existing ditch which will be eliminated as a result of the proposed dirt work. The eastern project area is adjacent to the western area, however,