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locations above and below the WRPs. The data show no evidence that the North WRP <br />has ever impacted groundwater or surface waters in excess of any water quality <br />standards. The North WRP was constructed above the 100 -year floodplain of Ralston <br />Creek (Wright Water Engineers, 2011) and is effectively isolated from direct contact with <br />surface or groundwater associated with the creek. <br />In July 2011, Cotter initiated a new study to further investigate potential impacts <br />associated with the WRPs by increasing the number of surface water quality monitoring <br />stations located along Ralston Creek adjacent to the WRPs, and by increasing the <br />frequency of sampling (typically several times per week). After five months of intensive <br />monitoring, there is no evidence of any measureable impacts associated with the North <br />WRP, but there is evidence of impacts associated with the South WRP. <br />The data indicates that groundwater flowing from Ralston Creek underneath the South <br />WRP in the vicinity of groundwater monitoring station MW -0 exceeds the uranium <br />standard (0.03 mg/L). During low- stream flow conditions in late summer and fall of <br />2011, surface water in the creek adjacent to lower portions of the South WRP (near <br />monitoring station SW -A001) showed evidence of slight seasonal impacts, though levels <br />remained well below the 0.03 mg/L standard. Further study of the South WRP is <br />required to better understand impact mechanisms, further quantify and identify precisely <br />where impacts are occurring, and determine effective remedial measures for permanent <br />mitigation. <br />In 2012, once the upper cutoff wall is in place and diverting water past the South WRP, <br />Cotter plans to conduct targeted geochemical studies of materials at depth adjacent to <br />lower portions of the South WRP. The objective is to characterize the depth and spatial <br />distribution of solid source term materials that, under current conditions, are in contact <br />with groundwater associated with Ralston Creek on a frequent or continual basis. One or <br />more peizometers or monitoring wells may also be installed along the toe of the South <br />WRP. <br />A detailed report regarding the WRPs is expected to be completed by the fourth quarter <br />of 2013. This report will provide: (1) detailed evidence and analysis confirming a lack <br />of impacts associated with the North WRP; (2) a comprehensive assessment of impacts <br />associated with the South WRP; and (3) proposed remedial measures to mitigate impacts <br />associated with the South WRP. The schedule for implementation of remedial measures <br />to address any impacts associated with the South WRP will depend on the remedial <br />measures selected and any lead time associated with design and permitting. <br />Implementation is currently expected to occur no later than the end of 2014. <br />Requirement 3: Cotter will investigate and assess any migration of mine pool water that may be <br />impacting shallow alluvial groundwater and /or Ralston Creek, and will provide a written <br />summary of the findings along with a plan and schedule for mitigation of any such impacts. <br />3 <br />