Laserfiche WebLink
4.6 Cover <br />The refuse pile will be contemporaneously reclaimed with an average of 18 to 24 inches of soil <br />cover obtained from the uppermost soil horizon(s) of colluvial soils stripped from the refuse pile <br />foundation area and revegetated with MCC's permanent seed mixture found in Table 37 of the <br />Permit document. As the coal refuse material and soils characteristics are similar to (but <br />expected to be more coarse- grained than) that of the existing LRP and RPE refuse piles, the <br />variance from four -feet of soil cover that was approved by the CDRMS for both the LRP and <br />RPE construction has been applied to the RPE East construction. <br />4.7 Haul Roads (Rule 2.05.3(3)(c) & 4.03.1) <br />Haul roads needed to support the RPE East refuse pile operations are shown on the permit drawings <br />in Appendix D. Provided in these drawings are haul road alignments, profiles, and typical sections. <br />Haul roads were designed to conform to requirements in Rule 4.03.1. Additional description of haul <br />road design is provided below. <br />4.7.1 Haul Road Horizontal and Vertical Alignment <br />Haul roads were laid out with a horizontal alignment as consistent with existing topography as <br />practicable, as required by Rule 4.03.1(3)(b). Roads do not cross streams or significant natural <br />drainageways. The typical design grade is 8 percent to facilitate efficient operation of haul trucks. <br />Maximum grade was kept to 10 percent or less. All design grades comply with requirements of Rule <br />4.03.1(3)(a). Detailed design will be conducted at all switchbacks as part of construction drawing <br />preparation and any necessary adjustments will be made to keep maximum slopes at 15 percent or <br />less. <br />4.7.2 Slope Stability <br />Haul roads were located on the most stable slopes available, as required by Rule 4.03.1(2)(a); <br />however, due to the steep natural slopes in the areas where haul roads must be constructed, additional <br />geotechnical measures will be required in some areas to establish stable slopes. A slope stability <br />analysis was conducted in accordance with a method developed by D.W. Taylor and W. Fellenius for <br />the anticipated range of soil conditions and the design slopes. The method is presented in <br />Appendix H. Calculations with this method are based on a range of cohesion for colluvium soils <br />anticipated in the construction area. Cohesion values were obtained from tests conducted on site <br />Revised March 19, 2010 <br />Z3� <br />P:\Mpls \06 CO\26 \06261003 MCC Refuse Pile Site Review & Permit\WorkFiles\Permil Application \Text\2010- 04- 19_RPE East Permit Application. doc16 <br />