2010-06-04_PERMIT FILE - C1982056A (9)

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TORT Mine Dewatering Well No 2 (MR08 228 MR -230) • In order to both supplement the existing mine dewatering/mine water supply capacity of the IORT Mine Dewatering Well No. 1, and to provide back -up pumping capabilities for the EMD, TCC will complete a second mine dewatering well and install associated ancillary equipment and facilities at the current l ORT Mine Dewatering Well location. Completion of the new mine dewatering well, l ORT Mine Dewatering Well No. 2, will involve: • Modification of the existing ASC drainage controls at the TORT location, stripping and stockpiling of approximately 240 cy of soil material to accommodate expansion of the existing pad area • Extension of the existing pad area through grading and controlled placement and compaction of approximately 350 cy of select fill materials • Drilling and casing of a 12 -inch diameter borehole approximately 1,360 feet to intersect the sealed and flooded EMD mine workings, and installation of a protected well -head and access manhole • Construction of a 1,000 foot 12 -inch HDPE pipeline to connect to the existing IORT/FCM -2 Transfer Pipeline, and installation of appropriate control valves to allow routing of the mine discharge water to either the Barricade Chamber/FCM -2 location or to the 6MN Mine Water Storage Reservoir • Extension of a new overhead powerline from Substation 11 to the l ORT facilities using the existing poles and 5 new poles, and installation of a new transformer on a small concrete pad at the l ORT facilities • Construction/installation of associated ancillary control and monitoring equipment The incremental surface disturbance associated with expansion of the TORT pad area will be less than 0.20 acres. All other activities will occur within existing disturbance areas. The location and configuration of the associated facilities modifications are shown on the Surface Facilities and Freshwater Systems Map, Map 24, and Drawing EX49P -F 1. • Modification of the existing ASC drainage controls will involve realignment of existing ditches and berms to accommodate the minor pad expansion. Recent inspections have indicated some minor siltation and erosion that has affected the effectiveness of existing drainage control structures, so TCC will take advantage of the opportunity to have equipment on -site to complete needed drainage structure maintenance. A conventional down -hole hammer drill -rig will be used to complete and case the No. 2 Well. It is anticipated that air or water will be used as the primary circulation medium, with use of drilling mud only if required to maintain the integrity of the drillhole and adequately flush drill cuttings. Cuttings and any drilling fluids will be retained in a portable cuttings pit. The No. 2 Well will be cased with welded steel casing, which will extend to within 10 feet of the abandoned and flooded EMD mine workings. The casing will be grouted in -place along its entire length, and a wellhead will be installed at the surface from which the pump will hang. A large- diameter CMP culvert will be cemented in -place around the well -head and fitted with a lockable cover. A multi -stage submersible pump will be installed in the well casing and connected to a power controller in the existing well house. The new powerline from Substation 11 will replace the existing powerline, bringing 12,470V power to the TORT Dewatering Installation Substation, where two transformers will convert the incoming power to 2,400V and feed power to the l ORT Dewatering Wells 1 and 2. The connecting pipeline tying to the IORT/FCM -2 Transfer Pipeline will be trenched and buried approximately 6 feet deep. The connecting pipeline will run from the new TORT Dewatering Well No. 2 to the l ORT/FCM -2 Transfer Pipeline, and then parallel the pipeline for approximately 1,000 feet to the junction with the IORT /6MN Transfer Pipeline. Flow in this pipeline section will be from the IORt Dewatering installation to the junction, and then back to the Barricade Chamber/FCM -s location. At this junction, a pre- fabricated CMP or concrete culvert will be installed as a manhole to provide access for pipeline control valves and inspection. A second discharge line will be extended approximately 3,900 feet from control valve manhole, to the south, extending under the 6MN Access Road, and discharging through the existing railroad culvert to Foidel Creek. The IORT Discharge Pipeline will be welded 12 -inch HDPE pipe, buried approximately 5 feet deep, discharging through a riprapped discharge • basin and channel to the existing culvert. For all pipeline construction, soil material will be removed and temporarily windrowed on one side of the trench, with trenched material placed to the other side. Once the pipeline is placed, properly bedded, connected to the IORT/FCM -2 Transfer Pipeline, and leak tested, trenched material will be backfilled and compacted, and soil material will be replaced over the excavation and reseeded. It is anticipated TR09 -70 2.05 -50.5 11/16/09