2018-01-03_PERMIT FILE - C1994082 (12)

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BACKFILLING AND GRADING Backfilling and Grading Procedures Rough grading will be performed with bulldozers, scrapers, maintainers and, occasionally the dragline. Bulldozers and scrapers are used for final grading. Seneca does not plan to remove any necessary reclamation equipment from the area of operation until final reclamation is completed. Typically, the process of grading begins with bulldozers building roadways into the ungraded spoil. Once sufficient access into the spoil is provided, dozers or scrapers move the spoil material in the direction and the amounts required to achieve the desired land form. The movement of spoil material is generally downslope, due to economic and safety considerations. Completion of rough backfilling and grading will occur within 180 days following final coal removal unless a variance has been approved. Backfilled materials shall be placed to minimize adverse effects on ground water, minimize off-site effects, and to support the approved postmining land use. SCC's experience has shown that grading two spoils simultaneously produces more desirable reclamation results than grading one spoil at a time. This is because the creation of graded slopes is primarily dependent upon the ability to perform "area grading" versus grading one spoil row. Because of many variables encountered in the overburden removal process, it is very difficult to predict the exact, final configuration of the spoil. Thus, the final planning for reclamation grading must be performed after the spoil is created in order to grade the disturbed areas in a diverse manner such that surface irregularities are created to minimize erosion, improve range and wildlife habitat, infiltration and improve soil moisture holding characteristics for the revegetation process. After mining progresses into a mining area and normal production operations are established, grading will generally be within two spoils. Creating an acceptable postmining landform is the primary consideration that determines the number of spoil that may exist in the field. Once the spoil piles are reduced to the point that equipment can be safety operated across the slope of the rough graded area, final grading will be done on the contour. Final interior spoil grading will produce a diverse topography with slopes generally no steeper than 5(h):1(v), except in areas where premining slopes were steeper than 5:1. Final highwalls will be reduced to slopes flatter than 3:1. In some acases backfill material is placed against undisturbed virgin ground at the top of a final highwall. Slopes may exceed 3H:1V in these isolated areas above the final highwall where the natural slope is originally steeper than 3H:1V. All backfilled slopes in disturbed area will be placed to achieve a static factor of safety of 1.3. TR -25 1 Revised 10/04