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1 <br />' as high risk. Water level declines in wells were generally slightly greater without the low <br />' permeability barrier. However, this difference was very slight due to the locations of the existing <br />wells. <br />' 4.fi.2 Ground Water Level Changes After Mining <br />' In order to estimate water level changes after mining, two simulations were performed. As with the <br />' mining simulations, one simulation was performed with the low permeability barrier and one was <br />performed without. The simulation without the barrier was performed to examine the ~•ensitivity of <br />' the water level impacts to the presence of the barrier. In order to simulate post-mining; conditions, <br />the model included the planned lined and unlined ponds, as presented in Appendix O Drains and <br />constant heads were also included in the mined areas to simulate the lowered water lev~:ls occurring <br />within the mine. The results of these simulations are summarized below. <br />' Post-mining water level elevations and drawdowns for the two simulations are presented in <br />' Appendices V through Y. Generally water level changes after mining are less than during mining. <br />As with the mining simulations, water level impacts occur primarily south of the South Branch. <br />' Water level declines in nearby wells range from a rise in water level to a decline of at~out ].33 feet <br />(moderate risk). As with the mining simulations, the well with the highest potenti~il water level <br />' change of 1,33 feet is the Atkins well (well number 11 on Figure 1). Post mining crawdowns in <br />other areas are also less than one foot, and vuere only considered a low risk to wells..4fter mining, <br />' water level declines at the well locations are very similar with and without the low permeability <br />barrier installed. <br />1 <br />4.7 Well Yields from Potentially Impacted Wells <br />As shown above, slight water level declines may occur to some water supply wells in the vicinity <br />' of the proposed mine. The modeled maximum water level decline in a well is on the order of 1.33 <br />feet (the Atkins well). This water level decline results from the proximity of the well to the mine <br />' boundary. Additional slight water level declines (greater than 0.1 feet) were noted i:1 ten of the 21 <br />-20- <br />1 lii</mp-Hiin'diu J~,o,'iivrc. hu. <br />