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West Elk Mine 2014 Annual Hydrology Report 33 <br />3.4 Underdrain and Mine Water Monitoring <br />Two underdrains were monitored in WY 2014. The underdrains are located at the lower <br />refuse pile (LRP) and at the refuse pile expansion (RPE) area. The LRP underdrain is <br />located above the sediment ditch at the base of the pile, east of former sediment pond <br />MB -2R. The RPE underdrain is located just above the RPE sediment pond. <br />Mine inflows are monitored and sampled at sites in the mine where discernible flows are <br />greater than 5 gallons per minute (gpm) and/or where flows are present for more than <br />seven consecutive days. If mine inflows are continuous, they are sampled for laboratory <br />analysis at least annually. In WY 2014, no mine inflows met the monitoring and <br />sampling criteria (MCC, 2015). The underdrain monitoring program details are <br />summarized in Table 8. <br />Table 8. Summary of the Underdrain and Mine Inflow Monitoring Program <br />Monitoring Site <br />Flow <br />Measurement <br />Field WQ <br />(H, EC, tem) <br />Annual Lab Water <br />Quality <br />Underdrains <br />LRP <br />3 x Year <br />3 x Year <br />Low Flow Period <br />RPE <br />3 x Year <br />3 x Year <br />Low Flow Period(" <br />Mine Inflows (if sampling criteria are met) <br />No mine inflows met sampling criteria in WY 2014 (MCC, 2015) <br />(1) Lab parameters include TDS, EC, pH, Ca, Mg, Na, K, SAR, hardness, bicarbonate, Cl, <br />Nitrite/Nitrate, PO4, SO4, Fe (tot & dissolved), Mn (tot & dissolved), Al, As (tot), Cd, Cu, Pb, Hg <br />(tot), Mb, Se (tot), Bo, Zn. <br />3.5 U.S. Forest Service Water Resources <br />MCC and the USFS District office in Paonia, Colorado have jointly agreed to formally <br />monitor the USFS-appropriated water resources that are located over mined and planned <br />longwall panels and within the angle -of -draw of potential surface impacts of the mining <br />operations. Observations are reported in the annual Fall Subsidence Reports submitted to <br />the CDRMS (MCC, 2015). The applicable appropriated water resources are listed in <br />Table 9 and shown on Map 37 in the Mine Permit document. <br />June 2015 HydroGeo, Inc. <br />