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Memo to Tony Waldron <br />Bowie IJo. 2 Geotechnical Adequacy <br />page 5 <br />addressed within the permit application. <br />Adequately addressing the slope stability (landsliding) hazard potential begins <br />with a thorough identification of the hazards on this specific site, as <br />recommended by Mr. Junge. Appropriate geotechnical reconnaissance should be <br />completed, including visual inspection, mapping and aerial photographic <br />examination. This should be followed by detailed investigations through test <br />pits an~j/or angering. Appropriate samples should be collected for field and <br />laborat~~ry determination of material strengths. After the specific type and <br />location of geologic hazards have been defined, the geotechnical engineers and <br />engineering geologists can identify the design parameters of concern. <br />Appropriate material strengths and failure plain orientations can then be <br />utilized to complete foundational analyses and stability analyses for the <br />proposed facilities. Finally, similar analyses should be performed to <br />demon~~trate the long term structural and geomorphic stability of proposed <br />reclaimed configurations for these surface facilities. Reports of all of these <br />activities must be reviewed and approved by the Division and incorporated into <br />the permit application by BRL. <br />Cuts and fills on landslide materials, such as those proposed to accommodate <br />the surface facilities at the Bowie No. 2 mine, can be particularly problematic. <br />The rernoval of lateral resistance and the placement of surcharge loads can <br />rejuvenate long-dormant landslide movement. Significant surcharges will <br />result from the placement of buildings, conveyors, road surfacing, coal and rock <br />stockpiles, coal silos and sediment ponds. Topographic modification and the <br />construction of drainage conveyances can introduce water into landslide <br />materials resulting in the rejuvenation of movement. Vibration from conveyors, <br />trucks, coal breakers, rock crushers, ventilation fans, and blasting can impose <br />dynami~~ loads on cuts and embankments, resulting in landslide rejuvenation. <br />Because of the unique peak strength versus ultimate strength relationships <br />commonly characteristic of landslide-prone materials, once initiated, <br />movement is extremely difficult to stop. <br />The Bowie No. 1 mine (previously the Orchard Valley mine) occupies areas with <br />similar geologic hazard designations. Similar facilities proposed, approved and <br />