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-31- Eastside's proposed mining operation during the first permit term will be limited to the E seam, accessed through the existing portals. Coal will be mined across the pitch of the 20 foot thick coal seam, which dips at 59o to the south. Extraction will be by a modified room and pillar method, with a maximum production of 250,000 tons per year during the first permit term. The proposed operation is in compliance with the requirements of this section. XVI. Backfillin and Gradin -- Rules 2.05.3 6 2.05.3 9 and 2.04.4 2 a 2.05.4 2 c 4.09, 4. 3, and 4.14 The application depicts a series of backfilled cross sections and postmining contours on pages 103 through 117, which represent approximate original contour in the reclaimed portal and facilities areas. Material balance calculations on page l0i of the application demonstrate that the proposed configuration can be achieved with material available on site. In the adequacy letter of July 25, 1984, the Division requested that the applicant demonstrate that the slope stability requirements of Rule 4.14.12(1)(b) would be achieved in the case of the steepest "worst case" slopes in the reclaimed portal vicinity as depicted on cross section drawing 26. The applicant has presented a simplistic comparison of the angle of repose and the tangent of the final slope to suggest that the static slope safety factor exceeds the required standard of 1.3. This simplistic approach assumes ideally granular materials which the local spoil and bedrock materials are not. The following stipulation is necessary: STIPULATION N0. 8 WITHIN 3 MONTHS OF PERMIT ISSUANCE, THE PERMITTEE WILL PREPARE AND SUBMIT TO THE DIVISION FOR APPROVAL AN APPROPRIATE ANALYTICAL DEMONSTRATION OF THE PROPOSED TOPOGRAPHY'S SLOPE STABILITY. "WORST CASE" SITUATIONS FROM CROSS SECTIONS IN THE APPLICATION WOULD BE ACCEPTABLE. THE REPORT PREPARED BY LAMBERT & ASSOCIATES INCLUDED IN THE APPLICATION SHOULD PROVIDE THE NECESSARY MATERIAL STRENGTH PARAMETERS. The application contains plans for a 30,800 yd3 underground development waste pile to be constructed at the head of a small valley on the west side of County Road 237, directly to the west of the surface facilities at the mine. The pile will be constructed in 2 foot compacted lifts to a maximum height of 50 feet with a 2:1 (horizontal vertical) outslope. As the pile increases in height (with subsequent lifts progressing up the valley) soil will be stripped ahead of the pile and 2 feet of soil cover will be replaced on the 2:1 slope and revegetated.