2015-07-21_REVISION - C1982056 - Laserfiche WebLink

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4) The proposed revision provides a description, plans, and drawings, describing the location, construction, use, maintenance, and removal of the 5MN borehole pad and pipeline. TC provides a general description of the use of the pipeline to facilitate dewatering of two bodies of water in the abandoned mine workings in the Wadge Seam above the Wolf creek Reserve. TC indicates this pipeline would facilitate the transport of mine water to the existing 6 -Main north Reservoir, the existing 10 -Right water pipeline, or a planned future passive treatment system. The Division cannot approve the use of this pipeline facility unless TC provides an updated plan for the protection of hydrologic balance in accordance with Rule 2.05.6(3) that accounts for the dewatering operation and demonstrates how the use of the pipeline will comply with Rule 4.04. TC needs to evaluate the quantity and quality of water to be dewatered and demonstrate that the capacity and capability of the existing water treatment and holding facilities can handle the dewatering operations, as a passive treatment system has not been submitted to the Division for review and approval. Response: As noted, TC is currently working on full-scale mine dewatering and treatment plans (passive treatment system) to address future drainage requirements, in order to safely mine the entire Wolf Creek Reserve. A contractor (CH2MHil1) has been selected, and is proceeding with a feasibility evaluation for the proposed treatment system. The proposed pipelines are being permitted at this time to allow construction during the limited 2015 construction field season, so that they will be available to meet the anticipated future long-term, full-scale dewatering requirements, but also to handle very limited initial dewatering and transfer of those limited flows to the existing mine water handling system (6MN Reservoir and 10 -Right Pipeline, as noted). From the 10 -Right Pipeline, the water can be moved through the existing system to the Fish Creek Water Treatment Facility (currently idle), the 18 -Left Pipeline and Borehole (existing — which would allow transfer of water to sealed and abandoned mine workings in the Western Mining District), the mine facilities area for use in the existing Washplant, or the existing transfer pipeline to the Barricade Chamber (routes water back underground for mine use). TC currently handles mine dewatering flows within the existing system, the current system is operated at levels which provide a significant margin between actual and design capacities, and any dewatering inputs to the system from the Wolf Creek Reserve would be limited by existing system capacity. Currently, TC's comprehensive mine water handling and recycling program balances mine water inputs with use so that there is negligible discharge to area streams (other than surface runoff which is routed through the existing drainage and sediment control system), and any discharge which does occur complies with applicable CDPS permit effluent limitations. Any flows from the initial mine dewatering would be limited by the capacity of the existing mine water handling system, with some flexibility to handle any excess water by routing it through the existing system to sealed and abandoned mine workings in the Western Mining District, consistent with current practice. It should be noted that the pipeline extension which would serve the potential future passive treatment system would be constructed, but would not be activated (shut-off valve at 6MN Reservoir) until such time as required permit approvals are obtained and construction of the passive treatment system is completed. Protection of the hydrologic balance and probable hydrologic consequences for the existing mine water handling system are addressed by the descriptive text in Section 2.05.6(3) (pages 2.05-127.1 through 2.05-167). Given that construction and use of the proposed pipelines is simply another connection to the existing system, would operate within the capacity limits and constraints of the existing system, and would not result in any significant changes or increased potential hydrologic impacts, additional plans and analysis are not necessary at this time. Status: Resolved.