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1.0 INTRODUCTION • <br />This report was prepared as a result of P.O.704964 requesting Maleki Technologies, Inc. <br />(MTI), to assist Bowie Resources, LLC (BRL), in a stability evaluation of the overburden <br />during development of a set; of mains in the Upper B Seam under the Terror Creek for <br />permitting purposes. The work was completed in two phases. Phase I encompassed the <br />design of a geotechnical data gathering plan and training of field personnel during data <br />collection (MTI 2003). The specific objective of the current work (phase 2) is to assist <br />Bowie Resources with a detailed stability evaluation of the overburden, above a 5- to 6- <br />entry main crossing under Terror Creek. <br />To characterize hydrogeologic and rock mass properties above these mains, BRL drilled <br />three geotechnical holes in the vicinity of the corridor (figure 1). These holes were <br />continuously cored below the bed rock and logged for lithology and structure. <br />Geophysical logs of electrical resistivity, radiation (both gamma ray and gamma-gamma <br />density), caliper, temperature; and sonic properties were also obtained for each hole. <br />C. <br />Selected core samples were sent to a laboratory for mechanical property testing to obtain <br />values to use in calculating rock mass quality and overburden stability. Once the holes <br />were drilled, they were used as groundwater monitoring wells for intervals above the B <br />Seam, within the B Seam, and below the B Seam in the Rollins Sandstone (figure 2). To <br />ensure technical quality, data collection was completed using guidelines proposed by the <br />International Society of Rock Mechanics (Brown 1981). <br />Both empirical and analytical techniques were used for assessing overburden stability in <br />near-seam strata and the stratigraphic units above. Near-seam stability was addressed <br />using both empirical and analytical techniques. An empirical technique developed by <br />National Institute for Occupational Health and Safety (NIOSH) was used to confirm that <br />the planned orientation was optimal to assure the stability of the rooms in respect to the <br />horizontal stress filed. Because pillar stability is important for controlling overburden <br />deformation, factors of safety were calculated for individual pillars by dividing pillar <br />strength to stress. Pillar strength was estimated using a method developed by NIOSH. 0 <br />Maleki Technologies, Inc. Page 2