2009-08-10_PERMIT FILE - C1982056A (4)

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1ORT/FCM-2 Transfer Pipeline and 1ORT/6MN Transfer Pipeline (MR07-224, MR08-2301 • A water line was installed from the IORT dewatering facility to FCM-2 to route water back into the mine for underground operations. The location of this water line is shown on Figure 161, 1996 Seismic Lines and Mine Water Discharge Return Line, East Mine District. Approximately 6,740 feet of 8-inch HDPE pipe was buried at 5 to 6 feet below grade from the TORT dewatering facility to FCM-2. This pipe will be left in place when no longer needed to support ongoing mining and related operations. As part of the 6MN Facilities project, TCC established a new pipeline running approximately 6,040 feet from the l ORT/FCM-2 Transfer Pipeline to the 6MN Mine Water Storage Reservoir and Million-Gallon Tank. The pipeline is constructed of 10-inch HDPE pipe, buried to a depth of approximately six feet, with one sub-grade crossing (bored under) of Fish Creek. Details of the Fish Creek pipeline crossing are presented in Exhibit 490, 6MN Mine Water Storage Reservoir - Design Drawings. Pipeline trenching operations were conducted using a track-hoe with the maximum working area assumed to be 40 feet wide. Approximately 7 acres were disturbed in construction of the original water line, with another 7.1 acres disturbed by the pipeline. Pipeline construction involved removing and temporarily windrowing soil materials along the edge of the pipeline corridor; trenching and temporary placement of the excavated material on the opposite side of the trench; bedding, placement, connection, and testing of the pipeline; controlled backfilling and compaction of the excavated material over the pipeline; and replacement, grading, and reseeding of the soil material over pipeline disturbance areas. Access manholes were established along the pipeline route for inspection and maintenance purposes. Soil materials were replaced following completion of pipeline installation. Reseeding of the disturbed areas will be completed during the first appropriate planting period following soil material replacement. Fresh-Water System Modification TCC's fresh-water system was modified to incorporate the million-gallon storage tank currently being used by • Colorado Yampa Coal Company. A water-line was constructed which ties-in the million-gallon tank, the existing well, and the new fresh-water borehole. The location of this system is shown on Map 24, Surface Facilities. Installation of the water-line required excavating a trench approximately 7 to 15 feet in depth. As shown on Map 24, Surface facilities, the majority of the ditch work occurred within previously disturbed areas. For the section of pipe laid in the disturbed area, a work corridor, approximately 30 feet wide, was used. The material excavated from the trench was placed adjacent to it, and after the pipe was placed the trench was backfilled. For the undisturbed area the topsoil, approximately 2 feet in depth, was removed from the work area, and temporarily stockpiled adjacent to it. After the trench was excavated, the water line placed, and the trench backfilled, the topsoil was replaced. A borehole, approximately 150 feet in depth, was drilled into the mine workings and cased. The borehole is approximately 12 inches in diameter, and the casing is a nominal 8" diameter. The annular space was grouted from the bottom to the top. The drill-pad required for this project was constructed on both disturbed and undisturbed land. The part constructed on the undisturbed area required salvaging approximately 24 inches of topsoil. The topsoil was temporarily stockpiled adjacent to the pad. Once the system was working, the topsoil was redistributed and seeded with the rangeland seed mixture. A temporary access road was constructed to the drill-site across an undisturbed area. Approximately 28 inches of topsoil was salvaged from the road corridor and temporarily windrowed to the side. After drilling and setting the casing the road was reclaimed by blading the topsoil back over the area, and the area seeded with the rangeland seed mixture. Any future access into the area will be along the existing railroad tracks. Given the limited amount of disturbance and rapid reclamation of the area it is requested that this area be identified as a Small Area Exemption. Therefore, no sediment control system will be installed. After the system is no longer needed, the borehole will be grouted from the bottom to the top. An Octo plug will be placed 10 feet below the surface, and the remainder of the hole will be backfilled with soil material. • MR09-238 2.05-51 06/26/09