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Direct Costs <br />1. Backfilling and grading <br />2. Topsoil replacement <br />3. Revegetation <br />4. Facility reclamation <br />Indirect Costs <br />1. Mobilization and demobilization <br />2. Engineering redesign fee <br />3. Contractor profit and overhead <br />4. Reclamation management fee <br />Backfilling and Grading <br />The first major phase in the reclamation of mined land is bat kfilling end grading the open <br />pits. Although this process is discussed in detail in the Backfilling and Grading Plan <br />found in Chapter 12, an unplanned cessation of mining will usually cause some deviation <br />from the original plan. Early cessation generally af~f acts the estimated postminin9 <br />topography, postminin9 drainages, and the resulting vol uinetric calculations. <br />The first step is the determination of volumes. Overburden/coal bore holes were located <br />in the 1994 open pit areas and used to determine en "average" or "typical" depth of <br />overburden. See Eahibic 12-1 for pi[ location. Values calculated from [he bore holes <br />were used in a range diagram computer program called RP.HGER. This range diagram was [he <br />basis for future volume calculations. A pit width of 110 feet was used for all pit areas. <br />Postmine slopes were then superimposed on the diagrams. For the sake of continuity, it <br />was estimated that all spoil would be graded towards the open pit at slopes between Sh:ty <br />and tOh:ty. All highwall slopes would be reduced to slopes between 2.Sh:1v and Sh:1v. <br />This produced a final topography that could not only be revegetated, but woultl also allow <br />drainage to flow through the pit area without impounding water. It was also assumed that <br />in all cases there would be four standing spoils behind the open pit. This is a very <br />conservative estimate because, in most cases, rec lametion grading is current to within two <br />spoil piles. <br />13-52 Revised 12/01/93 <br />