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• Random sample contamination often results in serious misinterpretations of the data. Many previously reported unsuitable copper, molybdenum, zinc, and especially lead concentrations were more apt to have been caused by drill stem grease contamination than natural mineralized strata. Dollhopf and Goering (1983), Dollhopf et al. (1981), Peabody Coal Company (1988), and Rochelle Coal Company (1984) all demonstrated significant contamination resulted from zinc, copper, molybdenum, and lead based drill stem joint ~ lubricants. A noncontamineting drill stem joint lubricant should be utilized when copper, lead, zinc, molybdenum, or other metals are included on the baseline parameter list. cThe excessive iron and manganese values present in the Phase I Yoest samples can be -attributed to the core samples having been contaminated by drill stem grease. Elevated values of iron and manganese appear systematically about every ten feet in each core section. This correlates closely with the frequency that each core barrel would have been emptied and regressed. Drilling end Sample Collection Methods. Overburden materials are generally sampled by utilizing one or more of the folloring three methods: continuous cores, cuttings or chips, • end hi Bh rell or outcrop grab samples. Barrett et al. (1980), Dollhopf et el. (1981), MDSL (1983), Xerrington (1983), YDEg (1985), and USDI.OSMRE (1985b) all recommend a combination of continuous core end drill cuttings locations be utilized for baseline overburden assessment studies. Continuous coring is primarily utilized during the first phase of a sampling program to accurately identify and document structure and stratigraphy. Subsequently during Phase II, rotary drilled chip samples are preferred to confirm chemical and physical trends because sampling is faster end more economical. Berth et al. (1981) recommends chip sampling for shallow overburden or where strata is homogenous. Herrington (1983) states overburden analyses results obtained from cores and cuttings to be similar when drilling fluids end other variables were controlled. Dollhopf et el. (1981) relied exclusively on chip sampling for all their selective handling studies. Peabody Coal Company (1987) shored li thologic descriptions and saturation percentages to be similar from a trinned hole location (i.e., Bore Hale 5086E was located less than 75 fee[ from Core Nole 4508E). Peabody drilled end colleeted samples from ten tore holes during Phase 1. A two-inch push core barrel was used to collect representative samples from the unconsolidated surtece, • while a 2-1/8 inch core barrel with a rock drill bit was utilized to collect subsurface consolidated material. Survey information for these ten cores is listed in Table 2. The locations of these holes are shorn on Exhibit b-4. 13