2008-09-16_PERMIT FILE - C1982056A (4)

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soil horizons is not significant over the areas to be affected by trenching. For the borehole drill-pad, individual soil horizons will be segregated. Generally, to avoid contamination of the windrowed soil material, excavated material will be temporarily placed on the opposite side of the disturbance area. BMP's for the construction activities include: • Minimizing the area of surface disturbance • Installation of the Foidel Creek crossing as a bored/jacked pipeline under the existing Foidel Creek road crossing culverts (avoids new surface disturbance of the stream channel and floodplain) • Completion of construction activities during the dry summer period • Placement of staked straw wattles downgradient of all surface disturbance areas to intercept any surface nuioff and trap associated suspended solids • Soil replacement and stabilization with temporary revegetation plantings immediately following completion of construction activities Where pipeline disturbance traverses steep slopes, additional staked straw wattles will be placed on contour to limit overland flow following revegetation seeding. Temporary drainage and sediment control measures will remain in-place until vegetation is sufficiently established to effectively control runoff, erosion, and sediment loss. Drainage and sediment control for the minor surface structures (borehole surface casing and any manhole(s)) will also utilize BMP's including the vegetative filter provided by temporary vegetative stabilization, and berms and/or wattles, as appropriate. As a relatively small (0.6 acres) linear surface disturbance, the additional disturbance required to either construct or intercept and route runoff from the disturbed area to a sedimentation pond is not warranted. The proposed BMP's have proven effective in controlling runoff and sedimentation from similar disturbances. Special design, construction, and operational measures were taken to assure that there will be no discharge or mixing of mine water with surface drainage. These measures include buried placement (approximately 5 feet below grade) of the Thickener Underflow Pipelines within a secondary containment pipe within and in proximity to the Foidel Creek drainage, and installation of differential pressure gauges, pump controls, and shut-off valves to provide for timely detection, shut-off, and isolation of the pipeline in the event of pipeline leakage. ~) Topsoil A narrative explaining the method of removal and the amount to be removed and the elan for stor eg_of topsoil subsoil and other material within the permit area subject to requirements of the topsoil removal performance standards of 4 06 2 This narrative shall specify the depth of material to be salvaged firm all disturbed areas based on the soil information required b~2 04.9 and shall specif}! the volume of each type of material to be salvaged. A man of any nronosed storage structures shall accompany the narrative: The mans shall be prepared according to the requirements of 2.10. RESPONSE See response to 2.05.4, Reclamation Plan, below for details concerning the Foidel Creek Mine. Twentymile Coal Company does not propose to disturb any additional land within the Fish Creek Tipple permit area. The Fish Creek Tipple and adjoining haulroad were constructed prior to the promulgation of regulations mandating topsoil salvage and storage. Thus, the best plant growth medium available is a mixture of spoil and soil materials which will be substituted for topsoil. This situation is further discussed within the Fish Creek Tipple/Loadout Appendix, pages 2.04-36 through 2.04-38 and pages 2.05-37 through 2.05-38 of Volume VIII. Eastern Mining District Dewatering Facility -The Eastern Mining District Dewatering Facility will require salvaging and stockpiling approximately 13,360 CY of topsoil from the access road and the facility site. During upgrading of the road, approximately 3,600 CY of topsoil will be windrowed to the side of the road. The topsoil along the length of the road is approximately 30 inches deep. The facility site will require salvaging and stockpiling approximately 8,300 CY of topsoil. The topsoil from the site area is approximately 30 inches deep. A test pit will be dug to verify the topsoil depth obtained from previous soil mapping work. The stockpiled topsoil, which is located within the pad area, will be stabilized with the topsoil stockpile stabilizing seed mixture. Additionally, approximately 6,295 CY of topsoil will be salvaged from the treatment pond site. This site has been `relocated closer to the road to facilitate delivery of chemicals. MR07-224 2.05-84.2 10/17/07