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3.0 2011 HYDROLOGIC MONITORING PROGRAM <br />The Williams Fork hydrologic monitoring program includes data collected specifically to meet requirements <br />of the DMG, as well as data collected to meet the requirements of the Colorado Wastewater Discharge Permit <br />System (CDPS). Note that "CDPS" parameters may have formerly been referred to as the National Pollutant <br />Discharge Elimination System (NPDES) in prior AHRs. Specific monitoring locations are illustrated on <br />Figure 2. <br />In June 2001, Technical Revision TR01 -32 was approved, allowing suspension of many DMG hydrologic <br />monitoring requirements while the mine was in temporary cessation (TC). In 2005 BTU EC began to <br />examine options for future re- activation of the mine site. In view of this considerations, BTU EC reverted <br />back to the active monitoring plan (pages 1 — 14 of Exhibit 29), during the second quarter of 2006. However, <br />as already indicated, interest in re- activating the mine has cooled. <br />Table 1 presents a summary of hydrologic monitoring requirements. Field parameters are outlined in Table 2. <br />Water quality monitoring includes field parameters (Table 2), surface water quality parameters (Table 3), and <br />CDPS parameters (Table 4). <br />3.1 Groundwater Monitoring <br />3.1.1 Bedrock Wells <br />Three sandstone aquifers are found beneath the subject site. In ascending order, they are: Trout Creek <br />Sandstone, Middle Sandstone, and Twentymile Sandstone. The Eagle No. 5 and Eagle No. 6 Mines are <br />located between the Trout Creek Sandstone and the Middle Sandstone. <br />Water Levels <br />The potentiometric surface represented by water level measurements in the Trout Creek Sandstone 5 Mine <br />well (Fig. 3). Historical annual water level fluctuations of 20 to 200 feet have been observed at this well but <br />no seasonal pattern is evident. Note that recent water levels (2006 to date) are lower than levels measured <br />pnor to Temporary Cessation. This drop is apparently from consistent subsurface dewatering with the No. 5 <br />mine pump. Levels remained relatively consistent from 2006 through 2008. There was a general rise in <br />water level of about 40 feet in 2009, through 2011. This is due to periodic down time from malfunctions of <br />the No. 5 mine pump. Dunng the last quarter of 2011, the pump failed, resulting in no discharge. The pump <br />is anticipated to be replaced in the spring of 2011. The former Okie Plaza Trout Creek well was abandoned <br />in June 1994 as mining advanced through its location. <br />Page 3 <br />G \Environmental \EMPIREWILLIAMS FORK\AHR\2011 \Empire2011AHR doe <br />