2010-09-02_REVISION - C1981012 (2)

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A *Kent Gorham - Page 2. - Sept. 1, 2010 The general plan of the Waste pile is included in the following table as prepared and certified by Agapito Associates Inc. Maximum Hei ht 30 ft Maximum Slope H ; V 1.5.•1.0 Maximum Lift Thickness 1.0 tt Minimum Compaction 90% Standard Proctor Moisture Content for Compaction +/- 2% of Standard Proctor Optimum 1. A detailed plan of the Pond Silt/Underground Development (Waste Pile) that is prepared by, or under the direction of, and certified by a qualified professional engineer, or by a professional geologist with assistance from experts in related fields such as surveying and landscape architecture (Rules 2.05.3(8)(a) 2.05.3(8)(a)(i)(A); 4.10.1(1)(a); 4.09.1(2)). The detailed design plan of the Waste pile is included in the attached design document included as Exhibit 37 - Development Waste Disposal Area Design. 2. A demonstration of that the Waste Pile has been designed so as to achieve a long- term static safety factor of 1.5 (Rules 4.10.1(1)(a); 4.09.1(1)(c); 4.09.1.(2); 4.10.4(2)). This demonstration should include a foundation analysis as required by Rule 4.09.1(14) During the week of June 7, 2010, Agapito Associates, Inc (AAI) personnel directed the drilling of an exploratory boring to obtain subsurface geotechnical information for design the DWDA at the New Elk Mine. At that time samples of the coal refuse and mine development waste were also obtained to determine their physical properties. Exhibit 37 addresses the engineering aspects of the (DWDA) design. The design document includes the detail of the design indicating a long term safety factor greater than 1.5. 3. A design for sub-drainage system (Rules 4.10.1(10) or 4.10.3(5); 4.10.1(1)(a); 4.09.1(2). The pile does not overlie any spring, therefore no sub-drainage system is required. 4. A discussion of the construction/compaction requirements for the Waste Pile that meet requirements of Rule 4.09.1(13); 4.10.4(3)(a), 4.10.4(3)(b) and 4.10.4(3)(c)). The proposed DWDA has a maximum width of approximately 168 feet. AAI recommends that a berm be constructed around the pile to collect any storm water runoff. A three foot tall berm will occupy approximately 14 feet per side, leaving 140 feet for the base of the pile. The minimum width at the top should not be less than 20 feet. Using a 2:1 horizontal: vertical slope, would result in a maximum height of 30 feet. This height was modeled using Geo-Slope's Slope/W software to model various