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Christy Woodward <br />September 17, 2008 <br />Page 7 <br />horizontal and from a location below the groundwater table, so that the wells will be free- <br />flowing once installed. <br />Currently, the Topaz and West Sunday mines are the only mines with underground workings <br />that are safely accessible below the groundwater table (i.e. these workings have been <br />rehabilitated, are actively pumped, and are ventilated for workers). However, active mining <br />in the lower portion of the Topaz mine precludes installation of monitoring wells at this time. <br />Therefore monitoring wells will be installed within the West Sunda- i : ne in order to <br />evaluate ambient groundwater quality and groundwater quality downgradient from the <br />workings. Groundwater quality data collected from these wells are expected to be generally <br />representative of all of the mines in the Sunday Mines Group, because all mines are located <br />within the same rock unit, at similar depths, and in similar hydrogeolog cal environments. <br />Five monitor wells will be installed within the West Sunday Mine, two upgradient wells and <br />three downgradient wells. fi. <br />Ambient Groundwater Quality <br />Two wells will be installed within the West Sunday Mine to evaluate ambient groundwater <br />quality. These monitoring wells will be installed within the western most drift of the mine <br />and in the Indian Drift, and will generally be drilled towards the north. The exact placement <br />of these monitoring wells will be determined based oh accessibility, ground conditions, and <br />hydrogeological observations. The general locations of West Sunday ambient monitoring well <br />locations are shown in Figure 4. A schematic of monitoring well design is shown as Figure 5. <br />Groundwater Quality Downgradient of Underground Workings <br />Groundwater downgradient from the underground workings will also be evaluated with <br />wells installed in the West Sund w mine'. Downgradient monitoring wells will consist of three <br />varying-depth"boreholes drilled adjacent to each other, at deep, middle, and shallow depths. <br />The intent of installing varying-depth boreholes is to evaluate the persistence of changes to <br />oxidation-reduction potential and dissolved concentrations of naturally occurring trace <br />elements. The general locations of the West Sunday downgradient monitoring well locations <br />are shown in Figure 4. A schematic of monitoring well design is shown as Figure 5. <br />Groundwater Sampling <br />Groundwater sampling will be conducted on a quarterly basis. The initial round of <br />groundwater sampling should approximately coincide with the fourth quarter of 2008. <br />Groundwater samples will be collected initially from the ambient groundwater monitoring <br />wells (2 samples), and from each borehole in the downgradient groundwater monitoring <br />wells (3 samples). <br />Ambient groundwater quality data will be collected for a period of 5 consecutive quarters as <br />required by HRMMR §6.4.20(9). The stipulated schedule for completion of work related to <br />potential DMO status for the Sunday Mines Group is March, 2009, which does not provide for