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Detailed design plans have not been provided for proposed future refuse disposal <br /> structures. Pursuant to Rule 2.05.3(8)(ii), detailed design plans will need to be provided <br /> prior to initiation of construction of Refuse Area 513, and subsequent refuse disposal <br /> structures to be developed over the life of the mine. <br /> A discussion regarding the handling and disposal of non-coal wastes is provided in <br /> Section IV.D., of the permit application package. <br /> Coal Processing Waste Disposal <br /> The permittee is disposing of coal processing wastes and mine development wastes in <br /> refuse piles located in the northeastern section of the mine plan area. This area is <br /> moderately sloping with the average slope of the profile of the valleys from the toe of <br /> the proposed fill to the top of the proposed fill being less than 10 degrees. No springs <br /> or perennial water courses exist in the area and ground water was not detected down to <br /> 44 feet. Coal processing wastes, amounting to approximately 450,000 tons per year, <br /> will consist of roof and floor rock, interburden and some coal. The development waste <br /> is material excavated during the construction of portals and entries to the mine. The <br /> wastes do not contain quantities of toxic- or acid-forming materials to create an acid or <br /> toxic leachate. This determination is based on the results of overburden analysis of <br /> waste material submitted to the regulatory agencies during the permit review period. <br /> The overburden analyses did reveal SAR values exceeding soil suitability criteria <br /> defined in Wyoming DEQ Guideline No. 1; however, this concern is ameliorated by <br /> replacement of cover soil 48 inches thick on RP-1, and at least 30 inches thick on other <br /> refuse areas. The Division has approved a cover replacement thickness of less than 4 <br /> feet, based on physical and chemical analyses of the refuse material, and further based <br /> on results of a five year "Refuse Area Revegetation Study" focusing on effects of <br /> varying cover thickness. The study final report was completed in December, 1996, and <br /> is included as Appendix A, of Section V, Vol. 4, of the permit application. Study <br /> results and analyses demonstrated that the requirements of Rule 4.15 can be met with <br /> less than four feet of refuse cover material (4.10.4(5)). <br /> The refuse disposal area is divided into 11 subareas. At the time the initial permit was <br /> approved, the permittee anticipated that only approximately ten acres would be in use at <br /> any one time to minimize the total disturbed area. However, some time after permit <br /> approval, when refuse disposal operations got underway, it became apparent that <br /> additional acreage would need to be developed in order to provide sufficient room for <br /> the drying of refuse to attain the appropriate moisture percentage necessary to meet <br /> compaction requirements. As a result, a technical revision to the permit was approved <br /> by the Division on September 26, 1985, which allowed Western Fuels to open an <br /> additional pair of sub-areas (Nos. 2 and 3) ahead of schedule to provide additional room <br /> for the drying of refuse. With the approval of the technical revision, the maximum <br /> anticipated disturbed area (excluding reclaimed acreage) at any one time has been <br /> increased to 120 acres. Refuse Areas 2, 3, and 4 were subsequently combined into a <br /> 30 <br />