2013-01-29_PERMIT FILE - C1981022A (3)

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Severe - 2.05.6 • Surface placement of coal (st«kpiling) and mine development waste • • Discharge of mine water to surface drainages • Mme water supplywithdrawals • Operation of drainage and sediment control structures Operational measures that will be implemented to mitigate these impacu are discussed below. In order to conserve available sod resources, vegetation and soil materials will be removed from all new mine disturbance areas prior to disturbance. While beneficial in terms of soil conservation and provision of a suitable growth medium to support final reclamation and revegetation efforts, this practice exposes underlying materials to potential erosion and loss, can increase suspended sediment levek in the runoff water, and may increase sediment contributions to area drainages. To maintain effective surface drainage, mitigate erosion, prevent loss of surficial materiais, and minimi>P additional contributions of suspended solids to azea drainages, OMI will route undisturbed drainage around disturbance areas, grade and stabilize disturbed areas to provide for effective drainage control, establish a drainage and sediment control network to collect and retain runoff from disturbed areas, reclaim disturbance areas as soon as operationally practical, and utilize other specific localized drainage and erosion control methods as necessary. These activities are discussed further in the following sections. In conjunction with mine development, facility installation, and ongoing coal refuse placement, OMI will grade, stabilize, and maintain all disturbed areas to provide for effective drainage and minimi>e potential erosion. Where appropriate, OMI will utilize l«alized grading and stabilization measures to effettivelycontrol and route drainage and minimi>P flowvel«ities. Examples would include graveled surfaces and the yard area drainage system in the mine facilities area; diversion collection ditches in active mine development waste placement areas; and drainage control berms utilized to isolate • disturbed area drainage. L«alized drainage control and grading measures will be supplemented by OMI's extensive drainage and sediment control network This network consisu of diversion ditches which route undisturbed runoff around or through disturbance areas, collection dashes which intercept disturbed area runoff and route it to sedimentation ponds, the sedimentation ponds, and ass«iated discharge structures. The drainage and sediment control system is described in Section 2.05.3, Mme Facilities, and design information and calculations are provided by the Drainage and Sediment Control Plan Maps, (Maps 2.05-M4 and the 2.05-MS Series) and byExhibic 2.05-E3, Drainage and Sediment Control Plan. The drainage and sedimentation control network will collect and retain disturbed area runoff allowing settlement of suspended solids and any necessary treatment prior to release to natural drainages. Sedimentation ponds will be operated under apphcable provisions of OMI's CDPS discharge permi[s. Compliance with the tertrts of these permiu will assure that downstream water quality impacts are minimi>Pd. All areas disturbed by mining and related operations will be reclaimed as soon as operationally practical following completion of mining if they are not to be used in conjunction with ongoing activities. Reclamation will involve removal of mine structures and facilities, backfilling and regrading disturbance areas, replacement of soil and substitute materiak, and revegetation. These activities are designed to re-establish drainage panems similar to those that existed prior to development and develop aself-sustaining vegetative community As a result of effective reclaration, infiltration and runoff relationships will be restored, limiting the time interval over which water quality impacts may occur. Where appropriate, OMI will utilize drainage control measures to prevent or mitigate potential impacts from ongoing operations. Such measures tray include use of surface binders and dust • suppressions agenu on haulage roads, soil substitute st«kpiles, and in active working areas, and placement of straw bales, sediment fence, erosion netting, mulch berms, stilling basins, sumps and other small structures to control and route drainage, limit surface erosion, m,mm~>P flow vel«ities, and reduce suspended sediment levels. PR04 2.05-79 Revised August 2000