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Detailed Design <br />Design Parameters: <br />Type Coal Mine Waste Disposal Area <br />Original is Gob Pile No. 2 <br />West Expansion is also known as Gob Pile No. 4 <br />Capacity Original - 1,075,000 cubic yards <br />West Expansion - 300,000 cubic yards <br />Slopes Original - No steeper than 5h:1 v slopes with 15' wide terraces on <br />50' intervals with the first 50 foot sloped no steeper than 2.5h:iv. <br />West Expansion - No steeper than 3h:1 v slopes with 15' wide <br />terraces on 50' intervals with the first 50 foot sloped no steeper <br />than 2.5h:1 v. All on a borrow (cut) slope no steeper than 2H:1 V. <br />Terraces Slope 5% back towards the pile and 2 to 5% towards collection <br />ditches <br />. Compaction 90 percent of the maximum dry density to prevent spontaneous <br />combustion and to provide the strength required for stability of the <br />refuse pile. Dry densities will be determined in accordance with <br />AASHTO T99-74. <br />Haul Road <br />Diversion Ditches <br />Subdrainage <br />System <br /> <br />TR-44 <br />10 percent maximum overall grade <br />Flows from the 100-year, 24-hour storm event. Upper diversion <br />ditches are designed to flow into the east and west collection <br />ditches and then into the sediment pond. <br />Original -Lateral drains as per the Stability Analysis section of this <br />report and an alternate rock under-drain system as per Rule <br />4.10.3(5). See page 5 Water Control Measures. <br />West Expansion - No subdrainage system. <br />3 - 02/07 <br />A/PRoveD <br />3~ze~o7 <br />