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~. <br />' outlined in TR-26 serves as the basis for development of the water management plan (TR-26) <br />' and this response plan. <br />2.1 Phase I -Interim Water Treatment <br />' Since July 1999, BMRI has been pumping from the seepage front (contained seeps and French <br />' drain) and the outlet of the West Pit (Wells M-18, -19, -20, -28, -and 29). Additional pumping <br />will also occw from the pit backfill (Wells BF-3, -4, or -5) (Figure 1-1). The pumping <br />' conducted to date has resulted in a water level decline in the West Pit of approximately 1 to 2 <br />feet. Continued pumping from the backfill wells will cause the water level in the West Pit to <br />' decline to a level that will reverse the hydraulic gradient between the West Pit and the Rito Seco. <br />A thorough discussion of the technical issues and benefits obtained from lowering the water level <br />' in the backfill are provided in Section 6.1.1 of TR-26. <br />' The water being pumped will be managed through active water treatment (with discharge of <br />treated water to the Rito Seco) and/or the pumped water will be evaporated using enhanced <br />' evaporation methods (see Section 6.1.2 of TR-6). This combination of management techniques <br />can be utilized until winter conditions establish in late fa(1 1994, at which time thy: management <br />' of this pumped water would be by active water treatment alone. After the hydraulic gradient <br />reversal has been verified the extraction rate will be reduced to the minimum flov~ rate required <br />' to maintain the reversal. Water management associated with these techniques ~n~ill allow the <br />consistent extraction and removal of 400 gpm of Rito Seco alluvial and West Pit bacl~ll water. <br />' The active water treatment process is designed to provide an influent flow rate of 600 gpm with a <br />' subsequent 400 gpm effluent rate. Reject concentrate from the system will comprise <br />approximately 200 gpm. This reject concentrate stream will be blended with the influent stream. <br />' The water treatment system for the minimal dischazge permit shall consist of four unit operations <br />' (Figure 2-1): (1) a prefiltration stage followed in sequence by a nanofiltration stake, and a post <br />filtration stage, (2) a sludge handling stage, (3) a concentrated reject handling st~.ge, and (4) a <br />membrane cleansing reject handling stage. <br />' Bathe Mountain Resources, Inc. Shepherd Miller, lnc. <br />' i~ny.ri..uoo:an~~~o:~~,wq~T,p.n.,.P~, ~a,w.:/a~.ix 4 SePrember l7. 1999 <br />