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Random sample contamination often results in serious misinterpretations <br /> of the data. Many previously reported unsuitable copper, molybdenum, <br /> zinc and especially lead concentrations were more apt to have been <br /> caused by drill stem grease contamination than natural mineralized <br /> strata. Dollhopf and Goering (1983), Dollhopf et al . (1981), Peabody <br /> Coal Company (1981) and Rochelle Coal Company (1984) all demonstrated <br /> that significant contamination resulted from zinc, copper, molybdenum <br /> and lead based drill stem joint lubricants. A noncontaminating drill <br /> stem joint lubricant should be utilized when copper, lead, zinc or <br /> molybdenum are included on the baseline parameter list. <br /> Peabody utilized a noncontaminating drill stem joint lubricant (lithium <br /> based) at all 1986 sample sites at Nucla Mine. All holes were drilled <br /> exclusively with air. <br /> Sample Methods. Overburden materials are generally sampled by utilizing <br /> one or more of the following three methods; continuous cores , <br /> cuttings or chips, and highwall or outcrop grab samples. Barrett et al . <br /> (1980) , Dollhopf et al . (1981) , MDSL (1983) , Harrington (1983) , WDEQ <br /> ( 1985) and USDI-OSM (1985b) all recommend that a combination of <br /> continuous core and drill cuttings locations be utilized for baseline <br /> OIU studies. Continuous coring is primarily utilized during the first <br /> phase of an OIU sampling program to document structure and stratigraphy. <br /> Subsequently during Phase II , rotary drilled chip samples are preferred <br /> to confirm chemical and physical trends because sampling is faster and <br /> more economical . Barth et al . (1981) recommends chip sampling for <br /> shallow overburden or where strata is homogenous. Harrington (1983) <br /> states that overburden analyses results obtained from cores and cuttings <br /> were similar when drilling fluids and other variables were controlled. <br /> Dollhopf et al . (1981) relied exclusively on chip sampling for all of <br /> their selective handling studies . Peabody Coal Company (1985) showed <br /> lithologic descriptions and saturation percentages to be similar from a <br /> twinned hole location (i .e. , bore hole 5086E was located less than 75 <br /> feet from core hole 4508E) . <br /> Peabody drilled and collected samples from one core hole (Site 873E) and <br /> three chip sample holes (Sites 874E, 875E and 876E) in Mine Areas 2 and <br /> 6-21 Revised 3/6/87 <br />