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should also be recorded on a regular basis, because slope displacements are often associated <br /> with mining activity. One method of cataloging this information is to plot the mining area and <br /> then note the number of tons mined and the data on a plan map of the mine. A histogram can be <br /> made of tons mined versus time, and this plot can then be compared to the total displacement <br /> graphs. <br /> 7.1 Monthly Slope Stability Report <br /> A formal, monthly slope stability report should be prepared. This report should contain <br /> the data listed in Table 3 and recommendations on the appropriate response to current <br /> instability. <br /> This should ensure that mine management receives the appropriate information and provides the <br /> discipline to document slope behavior. Direct, informal communication should also be <br /> maintained with mine operations on a daily basis when there is mining in an actively displacing <br /> area. <br /> 7.2 Interpreting Displacement Data <br /> Often there are several possible slope displacement modes for a mine slope, and it may <br /> not be clear, particularly at the onset of movement, which mode geometry is active. <br /> Displacement vectors are useful in determining the displacement geometry. Figure 4 is a <br /> hypothetical example showing a possible plane shear along a fault, Fl, and a possible wedge of <br /> faults, F2 and F3. The difference between the two would be significant since the FI plane <br /> shear would affect the building, while the wedge would not. Plotting the displacement vectors on <br /> a Schmidt plot shows that the displacement is in the direction of the wedge, not the plane shear. <br /> CC&V has committed to performing the recommended monitoring as outlined in the CNI 2011 <br /> Report. <br /> Blasting Effects on the Elkton Cresson Mine Road <br /> Blast monitoring has been performed at two seismic monitors at homes immediately south of the <br /> Elkton Cresson Mine Road. See the discussion for Structures 21 and 22. These monitors have <br /> been in place intermittently since 2011 and full time since 2013 which are recording blast <br /> information 24 hours per day. All measurements at the monitors have been well below the design <br /> limit of 0.5 inches per second. The monitors are set to trigger at 0.05 inches per second, which is <br /> ten times lower than the design velocity. These monitors record blast information 24 hours per <br /> day. <br /> Gary Horton is a Senior Environmental Coordinator at CC&V who conducts all blast monitoring <br /> and related work in and around the permit area. He has provided a letter report of the original <br /> blast design criteria, the pre-blast surveys, monitoring information and results. This report and <br /> related information is included in Attachment T-3. <br /> There has never been any visible evidence of damage to the Elkton Cresson Mine Road and <br /> Teller County has not notified the mine of any such damage. <br /> 31 <br />