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West Elk Mine 2007 Annual Hydrology Report 29 <br />is 3.4 Underdrain and Mine Water Monitoring <br />Two underdrains and nine mine water inflow sites were monitored in WY 2007. The underdrains <br />are located at the lower refuse pile (LRP) and at the refuse pile expansion (RPE). The LRP <br />underdrain is located above the sediment ditch at the base of the pile, east of sediment pond MB- <br />2R. The RPE underdrain is located just above the RPE sediment pond. Mine inflows are <br />monitored at sites where discernable flows are greater than 5 gallons per minute (gpm) and/or <br />where flows are present for more than 7 consecutive days. If mine inflows are continuous, they are <br />sampled for laboratory analysis at least annually. In WY 2007, no mine inflows met the sampling <br />criteria (MCC, 2008). The water quality data for the underdrams are presented in Appendix H. <br />Table 7. Summarv of the Underdrain and Mine Inflow Monitoring Program <br />• <br />Monitoring Site Flow Measurement Field WQ <br />(pH, cond, temp) Annual Lab Water <br />Quality <br />Underdrains <br />LRP 3 x Year 3 x Year Low Flow Period <br />RPE 3 x Year 3 x Year Low Flow Period <br />Mine inflows if sampling criteria are met <br />(1) Lab parameters include TDS, Cond., pH, Ca, Mg, Na, K, SAR, hardness, bicarb., Cl, Nitritc Nitrate, P04, SO4, Fe (tot & diss), Mn <br />(tot & diss), Al, As (tot), Cd, Cu, Pb, Hg (tot), Mb, Se (tot), Bo, Zn <br />3.5 U.S. Forest Service Water Resources <br /> <br />MCC and the U.S. Forest Service (USFS) District Office in Paonia, Colorado have jointly agreed <br />to informally monitor the USFS-appropriated water resources that are located over planned <br />longwall panels and within the angle-of-draw of potential surface impacts of the mining operations. <br />The applicable appropriated water resources are listed in Table 8 and shown on Map 3. <br />June 2008 HydroGeo, Inc.