Laserfiche WebLink
4.0 RPE East Refuse Pile Permit Design <br />The RPE East refuse pile design is presented on the permit drawings provided in Appendix D. The <br />layout of the refuse pile is based on geotechnical analysis and design provided in Section 2. Key <br />components of the refuse pile design are presented below. RPE East refuse storage capacity is shown <br />in Appendix G. <br />4.1 Stripping <br />Prior to placement of coal refuse in the RPE East refuse pile, the area being prepared for refuse <br />placement will be stripped of soils and colluvium down to bedrock. The colluvium will be placed in <br />horizontal windrows orientated generally perpendicular to the face of the refuse pile within the refuse <br />material to minimize interference with refuse pile drainage and to minimize potential for negative <br />impact to geotechnical stability. Where beneficial to the stability of the refuse pile, colluvium will <br />be mixed with wet refuse fines to absorb moisture. The extent of such areas will be kept to a <br />minimum to avoid developing low- permeability zones within the refuse pile. Vegetative soil stripped <br />from the refuse pile foundation zone will be used for contemporaneous reclamation as the face of the <br />refuse pile reaches design grade (Rule 4.13). <br />4.2 Buttress <br />A rock buttress will be constructed at the toe of the RPE East refuse pile to increase stability of the <br />refuse pile as required by Rule 4.09.1(10). Prior to buttress construction, the buttress area will be <br />stripped of soils and colluvium down to bedrock. A keyway cut will be placed at the toe of the <br />buttress to enhance stability. The buttress will consist of rock with colluvium on the upstream face <br />only, excavated from the initial refuse pile development area. The buttress will have a 1.511: IV <br />slopes on its north face (away from the refuse pile) and a 1H: 1V slope on the south face where refuse <br />will be placed. <br />The buttress will be constructed in phases. Phase 1 will be constructed in 2010. It is anticipated that <br />construction of Phases 2 and 3 will be completed by end of 2014, but the schedule could be extended <br />if rock buttress construction material is not available in adequate quantities from refuse pile <br />foundation excavation to meet this schedule, or if development of the refuse pile is delayed to <br />Revised August 31, 2010 4 -:. : r snw /'0 <br />P:\Mpls \06 CO\26\06261003 MCC Refuse Pile Site Review & Permit \WorkPiles\Permit Application \Text \2010- 08- 31_RPE East Permit Application 14 <br />MR.doc <br />f tj,2 -3e8 ?1-71 ro <br />