Laserfiche WebLink
• 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 snore 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, rtiolybdenuni <br />and lead based drill stem joint lubricants. A noncontaminating drill <br />stem joint lubricant shculd be utilized when copper, lead, zinc or <br />molybdenum are included en the baseline parameter list. <br />Peabody utilized a noncontaminating drill stem joint lubricant (lithium <br />based) at all 1986 sample sites at Nucla idine. 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. (1931), ~•1DSL (1983), Harrington (1983), WDEQ <br />(1985) and USDI-OSi~4 (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. (1961) 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 cf <br />their selective handling studies. Peabody Coal Company (1985) shoa:ed <br />lithologic descriptions and saturation percentages to be similar front a <br />twinned hole location (i.e., bore hole 5086E was located less than 75 <br />feet from core Bole 4508E). <br />Peabody drilled and collected samples from one corn 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 />