Reclamation efforts, including, but not limited to, backfilling, grading, topsoil replacement and revegetation, of all land that is disturbed by surface mining activities, shall occur as contemporaneously as practicable with mining operations. Unless otherwise approved by the Bureau, upon a demonstration by the permittee, through a detailed written analysis, in the permit application, that a variation is necessary: In contour mining operations, rough backfilling and grading shall follow coal removal by not more than 1500 linear feet; In area surface mining operations, rough backfilling and grading may not be more than three spoil ridges behind the pit being worked, the spoil from the active pit being considered the first ridge; In addition to, and notwithstanding the requirements of, §B(1) and (2) of this regulation, rough backfilling and grading shall begin within a time not to exceed 60 days of completion of all coal removal within a pit, designated area, or phase, and shall be continuous until completion; Within 5 days of completion of all coal removal on the permit area, rough backfilling and grading shall begin on the unreclaimed areas, and shall be continuous until completion, not to exceed 1 year after all coal removal. The number of open acres may not exceed the open acre limit. In order to minimize the amount of area that has not been backfilled and seeded by the close of a planting season, the Bureau may require backfilling, grading, topsoil redistribution, and seeding of open acres at times, rates, and locations that do not impinge upon the areas required for overburden removal, spoil placement, coal removal, approved haul roads, sediment control structures, and processing and shipping areas.