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ground water conditions during the driving of the Phillipson Tunnel are presented in Table 1 <br />of Appendix A. <br />A common method of evaluating tunnel inflow data is to plot the data as inflow- per -unit- <br />length -of- tunnel versus tunnel length. This method provides insight into the change of inflow <br />as the tunnel is advanced and whether the ground is becoming more or less productive. The <br />inflow data presented in Table 1 of Appendix A were plotted as inflow -per- unit - length -of- <br />tunnel versus tunnel length, and are presented in Figure 1 of Appendix A. This figure shows <br />that as the tunnel was driven, the inflow per unit length increased markedly as the Mosquito <br />Fault was intercepted. The increase in flow per unit length reflects the interception and <br />drainage of new water - bearing fractures. Figure 1 of Appendix A also shows that after the <br />initial increase of inflow, there is a general trend of decreasing inflow per unit length as fewer <br />water bearing fractures were being intercepted and previously intercepted fractures were being <br />drained. <br />The ground water inflow data from the Phillipson Tunnel show that the tunnel penetrated an <br />extremely permeable zone that was hydraulically separated from the rocks to the west. <br />Domenico and Schwartz (1990) discuss this phenomenon of tunnel construction where "such <br />inflows are frequently associated with gouge - containing fault zones. The low - permeability <br />gouge can act as a dam for perched water so that the removal of the gouge during construction <br />can cause the inflows." The records from the Phillipson Tunnel indicate the Mosquito Fault <br />zone acts as a low permeability barrier which controls east -west migration of ground water. If <br />the Mosquito Fault were permeable, greater amounts of ground water inflow would have been <br />observed in the Phillipson Tunnel prior to intercepting the Mosquito Fault. <br />Exploratory Water Supply Well <br />A record of recent ground water conditions in the Paleozoic bedrock west of the fault can be <br />obtained from the drilling log for an exploratory water supply well drilled at the Climax Mine <br />during November, 1994. The well log and additional data are presented in Appendix B. This <br />well, located north of the main gate, was originally drilled to provide a source of domestic <br />water to the mine. However, after drilling a total of 590 feet in depth, the well did not <br />encounter any significant ground water resources. The well yield was found to be less than 3 <br />