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• 3 (see Exhibits 6-3A and 12-1). Conditions were ideal for chip sampling <br />because the overburden was both dry and shallow (10 to 20 feet thick). <br />Chip samples were collected on two foot vertical increments from the <br />sail surface to the top of coal. Interburden and the weathered upper <br />Dakota coal seam, if present, were always sampled separately while five <br />to six feet of underburden was also sampled at all locations. <br />The core and chip samples were described in the field by the driller and <br />subsequently by a soil scientist. Standard geologic description <br />information such as lithology, color, hardness, grain size, boundary <br />conditions, wetness, and presence of fractures, pyrites, gypsum and <br />carbonates were included. The chip samples and cores were packaged in 6 <br />mil polyethylene by two foot increments and placed in standardized boxes <br />for shipment to the lab. At the lab (Intermountain Lab, Farmington, New <br />t4exico), chip samples and cores were air dried, split or composited <br />according to lithologic or stratigraphic sequence, crushed to pass a 10 <br />• mesh sieve and bagged. <br />Parameter Selection. Overburden and interburden information from the <br />existing Nucla Kline area (Permit C-008-81, Phase 1) was evaluated and <br />statistically summarized to select and justify the proposed chemical and <br />physical parameter list for P1ine Areas 2 and 3 (Phase II). Mean <br />overburden (above upper Dakota coal seam) and interburden (between upper <br />Dakota and lower Dakota coal seams) data from the seven Phase I drill <br />holes is summarized in Tables 6-6 and 6-1. The overburden and <br />interburden suitability information is presented by hole for each <br />parameter in Figures 6-3 through 6-9. Suitability criteria were <br />developed from Barth et al. (1981), hlunshower (1983) and the numerous <br />literature references included with Table 6-4 in the OIU Suitability - <br />Phase II section. The Colorado Water Quality and Overburden Geochem- <br />istry guidelines suggest 24 chemical and physical parameters to be <br />evaluated for "roof" and "floor" overburden. These parameters are <br />discussed in further detail for the seven Phase I core hale locations at <br />• the Nucla Mire site. <br />6-22 Revised 3!'0/31 <br />