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Environmental Protection Plan, Schwartzwalder Mine 15 -3 <br />FBRG, SW -ARH, and SW- LLHG). Groundwater is monitored quarterly in wells and sumps above and <br />within the central mine area. In addition, four new bedrock wells will be installed in 2011 and monitored <br />quarterly. The plan and schedule for installation of bedrock monitoring wells is described in Section 15(h). <br />(c) Short -Term Mitigation Options — Pump and Treat with Ion Exchange <br />The protection of water quality in Ralston Creek is advanced by the interception and treatment of alluvial <br />groundwater which would have reported to the creek. Groundwater in the alluvium is currently pumped <br />from a series of six sumps and wells, and is piped to the on -site water treatment plant for removal of <br />uranium by ion exchange. <br />Sump pumping and water treatment occurred from 1990 to 2002 and was reinitiated in July 2010. A 50- <br />gpm treatment system operated at Sump 1 from July 2 to July 30, 2010, during which time the system <br />treated up to 50 gpm continuously and achieved 99% reduction of uranium from collected groundwater. <br />The sump pumping system was expanded in 2010 to include six pumping stations (Sump 4, Sump 5, Sump <br />8, Sump 9, and MW9, in addition to Sump 1). Alluvial groundwater is pumped using submersible pumps <br />and piped to the water treatment plant through individual buried HDPE pipelines. The collection and <br />piping system is shown in Figure 15 -1. The water treatment plant was fully refurbished in 2010 to provide <br />appropriate secondary containment, pre - filtration, and four ion exchange vessels. Discharge from the <br />treatment system is routed through a 4 -inch HDPE line to outfall OO1A. <br />The uranium removal system is capable of treating up to 200 gpm. Equipment includes a surge tank, <br />prefiltration/controU manifold skid, four ion exchange treatment vessels which operate in series, valving, <br />and interconnecting piping. Prefiltration consists of a 4 -bank bag filter assembly for solids removal from <br />raw water. A schematic of the system is provided in Figure 15 -2. Controls include the ability to remotely <br />monitor system performance including real time flow and pressure at system monitoring points, alarm <br />conditions, etc. Manifold and valving provide the ability to advance treatment vessels in operating <br />sequence, isolate vessels for media exchange, and add additional treatment vessels as may be required. <br />Each treatment vessel has necessary valving and piping for isolation, operation and media exchanges. A <br />safety screen in the discharge line of each vessel is provided to prevent discharging of media or solids with <br />the treated water. <br />Operational data and compliance monitoring data collected since water treatment began indicate that the <br />ion exchange system is 99% effective in removing uranium from groundwater. <br />4109C.110510 Whetstone Associates <br />