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Bowie Mine, Terror Creek Reservoir Area <br />Pre-Subsidence Inspection <br />• <br />PROJECT NO. 27-218 <br />Area 3 is at the south end of the reservoir and includes the borrow area, the <br />eastern and western dam abutments as well as the up stream and downstream <br />faces of the dam. This area also includes the upstream and down stream ends of <br />the water outlet structure and Terror Creek below the dam. Instrumentation has <br />been installed along the crest and downstream face of the dam as part of several <br />unrelated studies of the condition of the dam. The studies by GRI Consultants <br />are referenced at the end of this report. Additional studies, which address the <br />potential effects of mining induced seismicity, are also referenced at the end of <br />this report. <br />We have assumed that the feature referred to as the borrow area was excavated <br />to produce material which was used to construct the dam (photo #11). We noted <br />some older soil slumps along the edges of the excavated area and groundwater <br />seeping from the exposed areas of the soil/bedrock contact. Ledges of <br />sandstone bedrock are visible in the upper parts of the excavation. <br />We also noted a three foot high scarp (photo #13) at the eastern upstream <br />abutment area of the dam which may be caused by soil creep during drawdown <br />of the water level in the reservoir. <br />The density and type of vegetation growing near the outflow pipe on the <br />downstream side of the dam (photo #14) may indicate that some minor seeping <br />has occurred around the pipe during spring and summer months when water <br />levels are at a maximum. <br />r?