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<br />elevation, and the mine was driven in a down-dip, <br />downgradient direction, the Division has seen mines <br />discharge under similar circumstances. <br />The fact that the mine was dewatered while in operation <br />suggests that the workings are in contact with or <br />hydraulic connection with an aquifer. The connection may <br />be via one or more of the three small faults encountered <br />within the No. 9 Mine. Although the piezometric surface <br />of the underlying aquifer is lower than the portal. it is <br />likely not lower than the lowest level of the workings. <br />Once hydraulic connection is established between the <br />workings and an aquifer, the flow characteristics of the <br />aquifer are impacted. The workings themselves create a <br />zone of greater porosity and permeability, thereby <br />forming a preferential flow path for the groundwater. <br />Whether or not the filling of the workings will result in <br />a discharge depends on many factors including, but not <br />limited to, the structural integrity of the affected <br />geologic formations, the amount of head built up in the <br />mine, the integrity of the portal seals, and the <br />permeability of the source aquifer. <br />Similarly, the fact that there are no historic springs in <br />the area does not logically lead to the conclusion that <br />no springs will develop as a result of underground <br />mining. Please have the operator consider the above <br />factors when revising the prediction regarding mine <br />discharges in the PHC. <br />If you or the operator have questions, please call. <br />cc: Larry Routten <br />