2016-06-08_PERMIT FILE - C1982056A

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pipeline, or the planned future passive mine water treatment system. It should be noted that the pu►np(s) for the Wolf Creek dewatering system will be installed and located underground in the mine workings, so no surface pumping installation or power will be required. In order to identify and prevent or minimize any potential environmental impacts associated with the proposed v,\ater transfer activities, TC reviewed the most recent grouse lek mapping, consulted with the CPW, and contracted a supplemental cultural resource survey for those areas not covered by previous survey work. These environmental analysis activities are documented by the cultural resource survey report, provided in Exhibit 6T, and wildlife consultation letter, included in Exhibit 23C. The main 51VIN Pipeline will connect to the 5MN Borehole riser, and extend approximately 3,200 feet to the west. Three "T's" and associated valving from this pipeline will allow routing of flows to the existing IORT Pipeline, the existing 6MN Reservoir, and the planned future passive mine water treatment system. The first lateral line will run approximately 620 feet from the main pipeline to the 6MN Pumphouse, and then extend another 500 feet to a "T' connection on the IORT Pipeline. The second lateral line will extend approximately 190 feet to the inlet of the 6MN Reservoir. The third lateral line will be installed at some future date, and will be designed to tie-in to the planned passive water treatment system. All piping will be 10 -inch thermally fused High -Density Polyethylene (HDPE) pipe, and will be buried a minimum of 5 -feet deep so that it is below the normal frost -line. 10 -foot diameter CMP access risers will be installed at the 5MN Borehole and the four other pipeline junctions to protect the associated valves, and provide inspection/maintenance access. Pipeline design information and drawings are provided in Exhibit 49CC. Installation of the 5MN Pipelines and access risers will involve placement of construction erosion controls (silt fence and/or straw wattles), removal and windrowing of soil materials; excavation, placement, and backfilling around the risers; trenching in most areas for pipeline placement; placement of suitable bedding materials; placement, connection, and pressure testing of the pipelines; backfilling and compaction of suitable fill materials around and over the pipeline, backfilling and compaction of the trench; regrading; replacement of soil materials; and revegetation of all disturbed areas. Maximum width of the pipeline corridor will be 40 feet. It is not anticipated that any of the planned activities will occur within stream buffer zones. The 5MN Borehole installation will remain in-place until it is no longer needed to support ongoing or anticipated Future mining operations. While the associated pipeline disturbance areas will essentially be reclaimed within a reasonable time period following pipeline installation, TC does not consider these areas to be reclaimed for purposes of reporting, since there is some potential that they may be re -disturbed for pipeline repair or maintenance in the future. At the time of final reclamation, the 5MN installation will be reclaimed by plugging and sealing the borehole, consistent with State Engineer requirements; cutting -off the borehole casing below grade, regrading the pad and road to their approximate original configuration, soil material replacement, and reseeding with TC's standard Rangeland Seed Mix Soil. For the pipeline installations, the access risers will be removed or demolished to 3 -feet belo�N -rade, and the pipelines will be cut-off below grade, capped, and abandoned in place. At that time the disturbance associated with the access risers will be regraded, soil materials replaced, and these areas as well as any pipeline areas requiring maintenance will be reseeded. Reseeding of the disturbed areas will be completed during the first appropriate planting period following soil material replacement. 10 -East Emergency Air Borehole (MR15-289) — TC plans to complete an Emergency Air Borehole above the WCR 10 -East Gateroads. The Borehole will initially be drilled as a corehole to obtain additional geologic information in this area; and will then be reamed to a larger diameter and cased and grouted to provide an emergency air -hole for air, supplies, and communications in this portion of the Wolf Creek Reserve, as a safety consideration, given the distance from existing ventilation and emergency escape hoist capabilities. The borehole will extend to a depth of approximately 1,600 feet, will be drilled and subsequently reamed to a 8.75 -inch diameter, and cased to a 4.5 -inch diameter. Initial drilling will focus on core recovery with a 3.5 to 4.0 inch corehole to depth. In the event any significant quantities of water are encountered during drilling, the option exists of drilling a large (1 1.0 to 13.0 inch) diameter borehole to a depth of approximately 800 feet, and placing and grouting in a 8.625 inch casing. MR 16-295 2.05-45.27 03/04/16