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Blue Mountain Energy 3 Illustration 61 <br />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-1R-Pond) located approximately 1100 feet to the south of the well through a <br />6-inch HDPE pipe laid on the surface. The DW-1R-Pond is located on the north bank of a tributary to Red <br />Wash. The location was chosen to place the pond on flatter slopes and as close as possible to the <br />tributary to 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 />The outfall from the DW-1R pond has been submitted to the Colorado Department of Public Health and <br />Environment Water Quality Control Division as Outfall 033A. Discharge from the pond will not happen <br />until the discharge permit is approved. Dewatering of the mine can continue in its current configuration <br />and discharge point until Outfall 033A is approved. If the outfall permit approval is delayed significantly, <br />another option will be to run a 6” HDPE pipe along existing roads to already approved Outfall 029. <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/l to <br />0.24 ml/l. This is half of the permitted level of 0.5 ml/l. 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