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George Patterson <br />Page 3 <br />December 22, 2014 <br />Analysis of Groundwater Quality Data <br />The Division reviewed 2011, 2012, and 2013 groundwater data in the AHRs with three <br />objectives: <br />• To determine if there are significant differences in concentrations of monitored <br />groundwater quality parameters between points upgradient and downgradient of the <br />Southfield workings. To assess this, the 2010 — 2012 data was analyzed to determine if <br />parameter concentrations in MW -65 were significantly greater than in MW -23 (no water <br />quality data was available for MW -16, since the well was reported as dry). <br />• To determine if there have been significant changes in concentrations of monitored <br />groundwater quality parameters over time. To assess this, data from previous time <br />periods (prior to the 2011 AHR) was compared to data in the 2011, 2012, and 2013 <br />AHRs. <br />• To compare the data to applicable groundwater standards. For the Southfield Mine <br />(which has a post- mining land use of rangeland), applicable standards are in Table 3, <br />Agricultural Standards, that are within the CDPHE Basic Standards for Groundwater <br />(Reg. 41). <br />The concentrations of several parameters were higher in MW -65 than in MW -23 (thus higher <br />downgradient than upgradient) during the 2011 — 2013 time period. These include: Total <br />Dissolved Solids (TDS); Bicarbonate as CaCO3; Chloride; Nitrogen as Ammonia; dissolved <br />Iron; and dissolved Manganese. These differences may be attributable to the Southfield Mine, <br />and are predicted in the PAP (see, for example, page 2.05.6 -40). They do not, however, exceed <br />applicable standards (as discussed below). <br />To analyze increases over time, the data from the 2011, 2012, and 2013 AHRs was compared to <br />historical AHR data for MW -65, the downgradient well. The only parameter that shows a <br />significant increase (10% or more, based on the long -term average) over all of the data from <br />1984 to 2013 is Nitrogen as Ammonia. The values in 2013 for MW -65 are 2.35 mg /L (June) and <br />2.49 mg /L (December); the 1984 — 2013 average is 1.30 mg /1. It is the opinion of the Division, <br />however, that this increase is not problematic for two reasons. First, the values are of the same <br />order of magnitude. Second, the historical maximum value for Nitrogen as Ammonia in MW -65 <br />is 2.50 mg /L, thus the values in 2011 — 2013 do not exceed the maximum from previous years. <br />The water quality standards used for this analysis include those parameters and values in Table 3 <br />of CDPHE Reg. 41 that overlap with the list of parameters monitored by Energy Fuels (as <br />required by the monitoring plan in Exhibit 25 of the PAP). These include: <br />• Dissolved Iron — 5 mg /L <br />• Dissolved Manganese - 0.2 mg /L <br />