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Introduction <br /> Blue Mountain Energy plans to dewater the B-seam underground working with a submersible pump in a <br /> new well named DW-1R. The well location was primarily determined by the end of the workings in the 1- <br /> Right set of entries, which is the lowest point within the active mine. The well will discharge to a small <br /> new sediment pond (DW-111-Pond) located approximately 1100 feet to the south of the well through a <br /> 6-inch HDPE pipe laid on the surface.The DW-111-Pond is located on the north bank of Red Wash.The <br /> location was chosen to place the pond on flatter slopes and as close as possible to Red Wash to <br /> minimize the amount of rip-rap channel that would need to be constructed. <br /> There will be two separate small areas of disturbance.The well pad for DW-1R will be within disturbance <br /> boundaries.The new DW-1R-Pond and a short access road and discharge channel will be new <br /> disturbance. <br /> Flow from the well will be about 400 gpm (0.89 cfs) but will fluctuate a little with mine water levels and <br /> pump wear. Initially,the pump will operate on short intervals where the pump will be on for a short <br /> time and off for a short time.As mining proceeds, more volume will become available underground and <br /> pumping intervals will lengthen. Total flow from the well will be recorded by a flow meter with a <br /> totalizer.A flow meter is an important part of monitoring the performance of the pump,so no other <br /> flumes or flow measurement devices are proposed. <br /> Hydrology <br /> As mentioned previously, there will be two separate small areas of disturbance—the well pad and the <br /> discharge pond. Runoff from both areas were modeled with SEDCAD. <br /> Hydrologic data including rainfall, soil type,and curve numbers can be found in Appendix A. <br /> Well Pad <br /> The well pad is approximately 0.25 acres and will be almost flat. Because vegetation cannot be allowed <br /> on the well pad, a small retention pond or trench was included off the low end of the pad to capture <br /> sediment runoff from the pad during a 10-year storm.Settleable solids will be reduced from 5 ml/I to <br /> 0.24 ml/l. This is half of the permitted level of 0.5 ml/I. No embankment will be constructed with the <br /> well pad trench. It will be cut below existing grade and will simply fill up and discharge to the same <br /> location and elevation it currently does.The 100-year storm was also modeled to verify the outlet to the <br /> existing grade is sufficient. SEDCAD calculations for the well pad area can be found in Appendix B <br /> Discharge Pond <br /> BME has historically included a small settling pond on similar dewatering facilities even though the <br /> water is typically clean and free of sediment.The purpose of the pond is to allow reaction time and <br /> settling in the unlikely event that sediment makes its way to the pump intake. Though small,the pond is <br /> much larger than it needs to be and reduces the settleable solids concentration to effectively 0.0 ml/I. <br /> The outlet of the discharge pond will be a simple broad crested weir with a width of three feet. Side <br /> slopes of 3:1 will result in a slightly lower peak elevation than calculated by SEDCAD.Again,SEDCAD <br /> Blue Mountain Energy 3 Illustration 61 <br />