Laserfiche WebLink
• feet. The toe buttress cut will also slightly increase the cover soil available. The toe <br />buttress cut area is about 460 square feet (per lineal foot). About 17 cubic yards of <br />cover soils will be obtained from each lineal foot of toe buttress excavated. The <br />amount of cover soil obtained from below the RDA is not critical for the first <br />segments. If additional cover soil is required to finish the segment then it can be <br />obtained from the area of the next segment. After completion of the first segment <br />the procedures used can be checked and adjusted for the next segment. <br />Compaction of the cover material is not required for the stability of the RDA <br />and we do not feel a compaction specification or testing is required for the cover soil <br />or topsoil. Normal placement and grading operations should provide sufficient <br />compaction of the surface to provide erosion protection. If erosion problems occur <br />• then it may become necessary to develop specific procedures such as track or wheel <br />rolling to compact the surface of the cover material. <br />Particles larger than 12 inches should be removed from cover material prior <br />~ to placement. Topsoil should be placed and revegetated as required by current <br />~~ permit procedures. A cover placement sequence is shown on Detail 9, Fig. 5. The <br />cover sequence was designed to provide a 100 foot buffer zone to reduce the <br />~ possibility of coal waste contaminating the surface of completed covered sections. <br />This distance can be adjusted based upon experience under actual construction <br />conditions. <br />~ Since the cover and topsoil will form the bench ditches, grading control of the <br />cover placement will be important to provide the recommended 0.5 percent slope to <br />the ditches. The slope of the benches is shown on Detail 8, Fig. 5. <br />• <br /> <br />21 <br /> <br />