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projection of areas graded are based upon certain basic considerations. First, • approximately two spoil rows are normally graded simultaneously once [he pit configurations become regular [o achieve the desired postmining land configuration and To effectively maintain topographic continuity between grading sequences. The number of spoils associated with irregular box cuts, certain inside or outside curves, short pits, facility areas, and haulage ramps may exceed four spoil rows to facilitate grading. Second, the time when grading of specific spoils can begin is based upon excavation cycle times and pit configuration. Rough bac kfilling and grading will be kept within four spoil ridges, except as discussed above. Cycle times ere dependent upon factors such as pit configurations, excavator performance, and customer demand. Third, once grading begins, the number of acres graded annually in a given pit is approximately equal to the number of acres disturbed annually. In certain circumstances, this generalization may not apply because of spoil material needed to achieve the designed postmining landform. For example, the backfilling end grading of box pit spoil, final hi9hwalls, and deep ramps typically require the movement of large volumes of spoil for great distances and requires up to two years after coal removal for final grading. Also, certain box cut spoil areas (uh ere box cut material is spoiled on recoverable coal) will be temporarily upgradeable until the recoverable coal is stripped (see Exhibit 19-1). All of the acres graded in a • given year are projected to be topsoiled and seeded as soon as possible based on the reclamation timetable, and viii represent reclaimed acres in Table 19-1. As tan be seen from Table 19-7, the maximum annual disturbance is estimated to be 406,5 acres in 7997. The most significant disturbance is advance topsoil removal which must be Completed by November 1 of each year in order to allow the overburden removal operation to continue during the winter and wet spring months. The efficient removal of topsoil at Seneca 11-4 is considered to be virtually impossible during the six-month period from November 1 to May 1 of any given year. Consequently, at the end of any given year, approximately one-third of the coal acreage [o be mined during the next year will have been disturbed by topsoil removal activities. The total annual disturbed acreage figures in the table include the coal areas mined and the advance topsoil removed areas, as cell as the other disturbances including spoil areas, existing and proposed haul roads, power lines, storage yards, and facilities. In order to avoid the confusion created by too many overlapping yearly lines, only the graded areas far each year are shown on the Reclamation Schedule, Exhibit 19-1. The facilities including utility lines, haul roads, drainage and • Sa Revised 04/24/91