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Future coal refuse placement and stockpile construction will utilize <br />essentially the same methods and sequence of activities which have been <br />utilized for ongoing refuse placement activities to date with the <br />exceptions of a reduction in lift thickness to two feet and layered <br />placement of coarse and fine refuse. These sequenced activities are as <br />follows: <br />o Extend existing stockpile collection ditches <br />o Remove topsoil and vegetative materials from expansion foundation <br />area <br />o Extend existing rock subdrains <br />o Place and compact refuse material according to design <br />o Grade top surface and side slopes to provide effective drainage <br />o Replace and grade topsoil <br />o Revegetate topsoiled areas <br />Existing perimeter collection ditches as shown on the Mine Area Surface <br />and Groundwater Hydrology Map, (Map 12), collect and route runoff from <br />disturbed refuse stockpile areas to existing Sedimentation Pond No. 4. <br />Existing collection ditches on the north and west side of the refuse pile <br />have been constructed to their design length. However, the south refuse <br />pile collection ditch has been extended only as far as was necessary to <br />control drainage from disturbed areas. As topsoil materials are stripped <br />ahead of refuse pile advance, extension of the south refuse pile <br />collection ditch will be sequenced to coincide with topsoil removal <br />operations so that disturbed area drainage is controlled at all times. <br />Detailed designs for drainage and sediment control structures associated <br />with the permanent coal refuse stockpile have been developed and are <br />presented in Exhibit 19, Drainage and Sediment Control Plan. Tracked <br />dozers, tractor scrapers and/or wheel loaders and trucks will be utilized <br />as appropriate for excavation and ditch construction. Generally, all <br />ditches will be trapezoidal in shape and have been designed to provide a <br />minimum of 1 foot of freeboard above the peak flow level for the design <br />event. <br />• <br />C' \ W O N K \PR1\XNlfiOf R I S. P E V <br />a~A,lmm 2.05.3-33R Revised April 1993 <br />