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Probable Hydrologic Consequences New Elk Mine 18 <br />successfully completed for the 2010 hydrologic investigation. Locations of the tested boreholes are shown <br />on Figure 5. <br />Permeability tests were performed using the United States Bureau of Reclamation constant head injection <br />method described by O'Rourke, et al. (1977). The general sequence of testing involved drilling the <br />borehole to total depth, airlifting the borehole for approximately 30 minutes to remove residual drilling <br />fluids, and then tripping the straddle packer assembly into the borehole to the lowest desired test interval. <br />Testing proceeded from the lowest section upward to evaluate saturated strata between the Allen and Green <br />coal seams. Once in place, the packers were inflated using nitrogen gas to shut in the section. After shut <br />in, the depth to water in the test section was allowed to stabilize and was measured in the standpipe using <br />an electrical water level sounder. Section pressures starting at shut in and continuing through the test were <br />monitored using an In Situ Level Troll 700 pressure transducer located in the center of the test interval. <br />Water was injected into the test intervals using a non - surging pump. Flow into the section was measured <br />using either a one or two -inch diameter totalizing flow meter. The injection pressure was monitored at the <br />surface using a gage located on the standpipe. The injection pressure was controlled by a bypass valve with <br />return hose located between the pump and the top of the standpipe. <br />Permeability tests for each interval were performed in three to five steps of about 3 to 6 minutes duration. <br />For each step, clean water was injected into the formation at constant pressure until the flow stabilized. <br />The flow was then recorded for at least three consecutive time intervals. Time intervals generally varied <br />from 1 to 2 minutes. Each section was tested at three to five pressure steps starting at about 10 to 15 psi <br />and stepping up to a maximum of about 60 psi on the surface gage before stepping back down to the initial <br />injection pressure. The maximum injection pressure did not exceed 0.5 psi per foot of depth to prevent <br />hydraulic fracturing of the bedrock. <br />Data from the packer tests were analyzed using the United States Bureau of Reclamation method presented <br />in O'Rourke et al. (1977): <br />K= Q <br />FH, <br />Where: K is hydraulic conductivity (ft /day) <br />Q is the injection rate (ft /day) <br />H is the effective head on the section (ft), <br />F is a shape factor described as: <br />2 irL <br />F– L <br />In — <br />rW <br />And: L is the length of the test section (ft); and <br />r is the radius of the borehole (ft). <br />4164A.110421 Whetstone Associates <br />rrD Gr, WAN Do 110 A /7l111 <br />