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West Elk Mrne <br />• sediment traps are shown on Map 54. MCC also utilizes sediment traps above the inlets to ponds <br />MB-3 and MB-4. <br />Genera/ Requirements for Sedimentation Control Facilities <br />All storm drainage/sediment control ponds have been designed in accordance with the requirements <br />of CMLRB Regulations for Coal Mining. In addition, all inspection, construction and <br />maintenance procedures conform to the requirements of these regulations. Flow meters have been <br />installed on all mine water intakes and discharges to measure flows. <br />Sedimentation ponds MB-1, MB-2R, MB-3, MB-4, and MB-5 have gated dewatering systems <br />located above the sediment level. Refer to the designs in Exhibit 43, 48 and Exhibit 66. The <br />dewatering system for SG-1 is shown in Exhibit 66. <br />Sedimentation Pond Oaeration <br />The following discussions describe significant features associated with and the operations of <br />each of the sedimentation ponds located at the West Elk Mine. MCC usually collects a pre- <br />discharge sample from the ponds to determine if the discharge will be in compliance with <br />MCC's NPDES permit, prior to opening the gate to discharge the pond. The pre-discharge <br />sample is analyzed for total suspended solids, as that is the parameter of concern to MCC. <br />MB-1 <br />Sediment pond MB-1 is atwo-celled pond designed to accept mine water and storm water <br />runoff. However, the majority of the mine water is now discharged through Lone Pine Gulch. <br />Currently, MB-1 handles very little, if any, mine water. The water enters the south cell of the <br />pond. There aze four pipes in the dike that separate the two cells to transfer water from the south <br />cell to the north cell if further treatment is necessary prior to dischazge. The primary spillway is <br />located in the north cell. The primary spillway is gated to better control discharges from the <br />pond and to assure the discharge will be in compliance with MCC's NPDES permit. The <br />emergency spillway is anopen-channel, rock-lined spillway. MB-1 is lined with a HDPE liner <br />that was installed in early 1998. The pond has been designed to hold three yeazs of sediment. <br />Other than the increased amount of sediment that resulted from the lazge mine water inflow <br />events in 1997, MCC's experience has been that the pond does not have to be cleaned of <br />sediment that often. MB-1 was last cleaned during the fourth quarter of 1997. MB-1 is sized to <br />contain the 100-year, 24-hour storm event, and/or MCC's water right for this pond. Piping is in <br />place to allow water from MB-1 to be pumped to FW-1 for mine water use. <br />MB-2R <br />Sediment pond MB-2R is designed to accept mine water and storm water runoff. This pond also <br />accepts runoff from the Lower Refuse Pile and treated discharge from the Wastewater Treatment <br />Plant. MB-2R is lined with a geotextile liner. There are four sediment traps that water flows <br />through prior to entering MB-2R. Two aze neaz the breaker building to pre-treat (settle) wash- <br />down water from the conveyors, reclaim tunnel, and other similar facilities. The third and forth <br />• sediment traps aze located immediately above the western and eastern inlet to the ponds. The <br />1.05-31 Revised June 2005 PRIO; Rev. January 2006; Rev. March 2006; Rev. Apri12006 PR/0, May 2006 PR/0 <br />