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7. Drainage design for the toe-of--cut ditch along the steep (10%) segment of the <br />ditch may not comply with the ditch protection requirements of 4.03.2(4). The <br />ditch design may need to be divided into two sections. The lower section appears <br />to be a 2% grade, and would be the more demanding on ditch configuration, with <br />the exception of ditch protection. The Structure #6 ditch was designed for a <br />2°!° grade. A section of the ditch is at a design grade of 10%. Please add to <br />the design package a ditch design for the 10% grade section. Please provide <br />for the hydraulic jump anticipated at the break to a 2% grade. <br />8. The requirement of Rule 4.03.2(4)(d) that the road surface be sloped as sufficient <br />to prevent ponding of water and erosion of the road surface is not addressed. <br />Please add to the specifications for the access road a crown, or a side-slope to <br />the wearing surface, to meet the requirements of this rule. <br />9. There is reference to gravel surfacing in the SEDCAD run, page RSS-1, but the <br />specification should be included in the road design specifications. Please add to <br />the design specification of the access road a requirement for a gravel (or <br />other) wearing surface, and specify that acid-forming ortoxic-forming <br />substances shall not be used in the road surfacing, to demonstrate <br />compliance with 4.03.2(5)(a) and (b). <br />2.05.3(4) Ponds, impoundments, other treatment facilities and diversions <br />10. It appears that the proposed down-sized Sediment Pond 8 would be located within <br />the area delineated as "Industrial/Commercial" Postmining Land Use on new <br />Exhibit 63. Because Sediment Pond 8 is the primary sediment treatment facility <br />for reclaimed slopes of the RSRDA refuse area, the pond will need to remain in <br />place to serve that function until such time thaC appropriate documentation is <br />provided to allow for pond removal, in accordance with provisions of Rule 4.05. <br />It maybe the case that SCC will be prepared to request bond release for the <br />Alternative Land Use area before a demonstration for sediment pond removal is <br />made. As such, it would seem to be appropriate that the proposed postmining <br />land use boundaries be re-drawn, to include the down-sized Sediment Pond 8 <br />within the "Fish and Wildlife Habitat" postmining land use area. Please <br />provided amended maps as appropriate to include Sediment Pond 8 in the <br />"Fish and Wildlife Habitat" postmining land use area, or provide rationale <br />and regulatory basis for an approvable alternative. <br />11. Our understanding is that the downsized Pond 8 would be designed for full <br />containment of the 10-year, 24-hour storm event with no de-watering device. <br />Please confirm that this is the case, and please address the nature of the <br />of5cial CDPS outfall for the pond (such as a flume or other measuring <br />device), within the appropriate section of the permit narrative. Also, please <br />include reference in the text to maintenance of a rain guage (or gauges) in the <br />watershed, which could be used for documentation of storm event <br />3 <br />