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inspections at BRL during 2003 and 2004 (Stover 2003, 2004). On November 19, 2003, <br />Stover noted a rock fall near the northern boundary of the D9 panel. As illustrated in <br />figure 10, this event appear to be localized spalling of rocks from a fluvial sandstone <br />escarpment. <br />Unlike this reported local spalling event, regional spalling from the cliff-forming <br />Castlegate Sandstone has been subject to long-term studies by Utah operators and Forest <br />Service resource specialists (Maleki and others 2001). The study shows higher potential <br />for escarpment instability depending on geologic and geometric factors including the <br />orientation of escarpments in respect to longwall panels, jointing, topographic relief, etc. <br />Escarpments oriented near parallel to the longwall panels, for instance, are more likely to <br />experience instability than the ones oriented perpendicular to it. <br />Maleki Technologies, Inc. Page 22 <br />