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• <br />Section 779.14(aj Continued. <br />Rule 2.04.6 <br />Therefore, the present evaluation will be limited to a discussion of the <br />characteristics of the strata to be affected by any future mining in the <br />Pit 2 and 3 areas. <br />In the present evaluation, a total of 12 overburden geochemical holes were <br />evaluated. For these holes, the corresponding depth intervals sampled, <br />lithological descriptions, and drillhole locations are presented by Table <br />5a, List of Drillholes Sampled for Overburden Analysis, Exhibit 22, <br />Drillhole Logs, and the Kerr Mine Area Geology Map (Map 6a). <br />Drilling methods for overburden sample holes are documented by dri]lers <br />logs. Examination of the available information suggests that drilling <br />fluids in the form of mud or foam were used on many of the holes. <br />Research by Power and Sandoval (1916), Dollhopf and Obbers (1981) and <br />Dollhopf and Goering (1983) has shown that several contaminants exist in <br />drilling fluids and greases. Therefore, the evaluation of overburden <br />geochemical data included an assessment of the possibility of sample <br />contamination as indicated by suspect values or documentation on the use <br />of specific drilling fluids in drilling operations. <br />According to the lithologic logs, several of the holes were drilled as <br />"continuous cores' while logs for other holes (28-80-28c) note in3ection <br />of drilling fluids in order to maintain circulation. Discussions with Jay <br />James and Larry Henchei, formerly of Energy Fuels, the geologists involved <br />in the drilling of almost all of these holes, indicate that notations of <br />drill fluid infection on the log sheets can be interpreted to mean that <br />drilling mud was infected into the holes. They also reported that for <br />many holes where chip sampling was indicated, foam or gel in,)ection was <br />necessary to maintain circulation and lift the drill cuttings. <br />In addition to the drilling conducted by Kerr in 1979 and 1980, the USGS <br />• drilled six (6) geochemical holes in the McCallum Study Area (USDI 1983). <br />Note of these holes intercepted the geologic strata in the immediate mine <br />779-17 b Revised-Apri1,1990 <br />