Laserfiche WebLink
11. There will be some long-term settlement of both disposal areas. We recommend overbuild of <br />approximately 5 percent in the central portion of both fill areas in order to maintain long-term drainage. The <br />surface of the fill should be designed with a slope of 5 percent away from the head of the fill. The fills should <br />drain to ditches on both sides of the fill. <br />Given that these drainage features encompass the entire temporary clay stockpile, topsoil pile, and light-use road, <br />and that these disturbances represent only a small portion of the total excess overburden stockpile area, they should <br />provide effective drainage and sediment control for the proposed temporary activities. A temporary fueling station, <br />consisting of a fuel tank and lined secondary containment, will also be established at the stockpile location. The <br />stockpiled clay will be recovered and placed as cover material on the western slope of the Refuse Pile as soon as <br />ongoing refuse placement and grading bring this area to the final design elevation and grade. The light-use road <br />will be narrowed and ripped, stockpiled topsoil will be replaced on the associated disturbance areas, and all <br />disturbed areas will be reseeded with the permanent rangeland seed mix. <br />4) Subsurface and Surface Drainage -Small drainage ditches will be constructed downslope of the temporary <br />stockpiles to minimize water running over and down finished slopes of the CRDA. Also, it was recommended in <br />Exhibit 26A-1 that temporary drainage ditches be established along the eastern edge of the benches as they are <br />constructed, to prevent excessive surface runoff from flowing over the finished/compacted slope of the CRDA. <br />The specific recommendations for these temporary drainages are presented in Exhibit 26A-1. <br />Coal Refuse Disposal Area Expansion - Geotechnical Investigations (MR07-2261 <br />Site geotechnical investigations are required to provide foundation and soils information for design, permitting, and <br />construction of the Coal Refuse Disposal Area Expansion. The area proposed for the Refuse Pile Expansion is an <br />area of reclaimed mine spoils immediately adjacent and to the east of the existing CRDA, as shown on the <br />accompanying figure. Site geotechnical investigations for the CRDA Expansion will involve completion of six to <br />eight, 4-inch hollow-stem auger sample holes to depths of 20-30 feet; excavation of four to six shallow (ten to <br />fifteen feet in depth) backhoe test pits; and collection,, examination, and testing of soil samples. There will be a <br />total of no more than twelve auger holes and test pits. No new roads will be built, sample locations will be <br />accessed overland using rubber-tired equipment, and access will be limited to periods when the ground is dry or <br />frozen in order to minimize surface disturbance. In order to minimize surface disturbance, soil removal will be <br />limited to the immediate area of each auger-hole or test pit, with soil material being windrowed to the side of the <br />disturbance area, and re-spread immediately following completion of drilling/excavation/sampling and backfilling. <br />Site runoff from the limited disturbance areas will be addressed through the use of alternative sediment controls <br />consisting of straw wattles, placed ands staked immediately downgradient of each disturbance area. Auger drilling <br />is a dry drilling operation, so no mud pits will be required, and no discharge of drilling fluids will occur. Because <br />the auger-holes and test pits will be in reclaimed mine spoils on a hillslope, the potential for intercepting any <br />significant quantities of ground water is negligible. Air will not be used a circulation medium, so dust generation is <br />not a concern. <br />Immediately following completion of sampling, each auger-hole and test pit will be backfilled with excavated <br />material and leveled, with seeding of all sample sites following, either prior to snowfall, or in early spring when <br />ground conditions permit. It should be noted that all minor surface disturbance associated with the site <br />geotechnical investigations falls within both previously disturbed areas, and the footprint of the proposed Refuse <br />Pile Expansion, and will be re-disturbed by Refuse Pile Expansion foundation preparation activities. <br />Concerning the Fish Creek Tipple, no excess spoil or underground development waste will be generated in connection <br />with the operation. Thus, the requirements of this section and Rule 4.09 are not applicable. <br />~9) Return of Coal Mine Waste to Abandoned Workings <br />~~Erzeh plan shall describe the desi~ operation gild maintenance of auk, proposal coal <br />processing mine waste clis~osal facility including flow diagrams and any other necessary diawin4~s and mays, which. <br />must meet the standards of ~ 10 far the a~~proval of both the Division and the Mine Safety and I-Iealth Adnunistration <br />in accordance with 4.11.3, <br />2.05-97.2 ~~~ ~ ~ ' ~.. ~;'T.."r.~..} <br />MR08-233 12/09/08 <br />