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Rule 4.09.2(2)(c) A filter system to insure the properfunctioning ofthe rock underdrain system shall <br />be designed and constructed using standard geotechnical engineering methods. <br />See Rule 4.09.1(13) above. <br />Rule 4.09.2(2)(d) In constructing the underdrains, no more than 10 percent of the rock may be less <br />than 12 inches in size and no single rock may be larger than 25 percent of the width of the drain. <br />The minimum size of the main underdrain shall be: <br />To[a/Amount of Fill Predominant Type of Minimum Size of <br />Material Frtt Material Drain, to feet <br /> Width Height <br />Less than I,000,OOOyd' Sandstone /0 9 <br /> Shale 16 8 <br />More thanl,000,OOOydj Sandstone t6 g <br /> Shale !6 /6 <br />The application is in compliance with this rule. See Figure 5 of Exhibit 21 Item 1. <br />Rule 4.09.2(3) Excess spoil shall be and placed in a controlled manner and concurrently compacted <br />as specified by the Division, in horizontal lifts demonstrated in accordance with 2.05.3(6)(6), (c) and <br />(d) to achieve or provide the following: <br />Rule 4.09.2(3)(a) Achieve densities designed to ensure mass stability; <br />Rule 4.09.2(3)(6) Prevent mass movement; <br />Rule 4.09.2(3)(c) Avoid contamination of the rock underdrain of rock core; and <br />Rule 4.09.2(3)(d) Prevent formation of voids. <br />See Rules 4.09.1(1) and (7) above. <br />Rule 4.09.2(4) The final configuration of the fill shall be suitable for the approved postmining land <br />use. Terraces may be constructed on the outslope of the fill if required for stability, control of <br />erosion, to conserve soil moisture, or to facilitate the approved postmining land use. <br />See Rule 4.09.1(8) above. <br />Rule 4.09.2(5) Drainage shall not be directed over the outslope of the f ll. <br />The proposed plan does not fully comply with this requirement. A suggested comment to the <br />applicant is: Please reshape the fill (and backtill of pits if necessary) to direct surface runoff <br />into perimeter relief drains (ditches) of the fill. These perimeter drains should be located in in- <br />