2011-03-18_PERMIT FILE - C1981044A (4)

Home Browse Search

Waste Disnosal Site The CMLRD approved this waste disposal site in 1983. Mr. Robert W. Thompson of CTL/Thompson, Inc. of Denver, Colorado performed the geotechnical design of the waste disposal site. The design methodology and operation restrictions of the site are presented in Exhibit 2i, Waste Disposal Site. No. 9 Portal Waste Disposal Site The No. 9 Portal excavation is the location for the additional waste disposal site. The decision to use of the No. 9 Portal excavation as a waste disposal site was reached for four (4) basic reasons: 1) the availability of the site, 2) [he fact that 45,000 cu-yd of coarse reject is already approved for disposal, 3) all disposal would be below the original ground surface, and 4) utilization of the No. 9 excavation area may eliminate the need to expand the approved waste disposal site if additional capacity is required, For location of the No. 9 Portal waste disposal site, please refer to the Structures and Renewable Resources Map {Map 25). Backeround. In the original EC Permit (1983), it was planned to backfill the No. 9 portal excavation with the previously excavated material In 1984 during the construction of the 100,000 ton raw coal storage pile, 45,000 cu-yd of this same excavated material was utilized in the construction of the coal storage pile pad. It was agreed, at that time, to replace this 45,000 cu-yds with coarse reject material. The coarse reject was to be placed within the No. 9 portal excavation backfill. Disnosal Pile Construction Details. The No. 9 Portal excavation was prepared for waste disposal by first, covering the portal entries with a minimum of 15' of material. Second, the exposed coal seam ("P" coal seam) was covered with a minimum of four (4) feet of inert material. Please refer to the No. 9 Portal-Waste Disposal Site (Map 28). Alt associated mining equipment including conveyors and structures, ventilation fans, electrical substations, and associated mining scrap would be removed prior to the backfilling operation. Backfilling the excavation a minimum of 15 feet above the portals will seal the portal entries. This sealing plan has been approved by MSHA. Backfilling and covering of the coal seam was and will be accomplished through the use of front-end loaders, end dump trucks, bulldozers, and graders. The shop/office building, scrap-yard, and associated pad will remain intact until no longer needed by EC. Once the backfilling and covering of the coal seams is complete, the excavation would be available for waste disposal consisting mainly of coarse reject material from the rotary breaker. Since the No. 9 excavation waste disposal area is below ground disposal site, all the restrictions placed on the approved waste disposal site would not apply. However, all disposal activities will conform to the approved MSHA plan. The approved MSHA plan will be submitted to the CMLRD upon receipt. It is planned to place the waste material in the excavation in approximately two (2) foot lifts. The operation of the front-end loaders, end-dump trucks, bulldozers, and graders will effectively compact [he waste material. Design details and cross-sections for the No. 9 Portal waste disposal site are presented on the No. 9 Portal - Was[e Disposal Site Map (Map 28). Once [he waste material has reached a height of approximately four (4) feet below the planned reclaimed surface, the material will be covered with a minimum of four (4) feet of backfill material. Backfill material will be taken from the material originally excavated from the No. 9 Portal site. Since a majority of the No. 9 Portal excavation will be back- filled with coarse reject material, there will be an excess of material left from the original excavation. This excess material will be used to cover the No. 9 portal pad area with a minimum of four (4) feet of material. Please refer to the Reclamation Plan Map (Map 29) for the final post-mining topography of the No. 9 Portal area. The originally proposed post-mining land use (cropland) will be retained for the No. 9 portal area. The final reclamation plans for the No. 9 Portal area are presented in Section 2.05.4, Reclamation Plan Permit Revision 04-34 2.05-21 Revised 7/2/04