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Subsidence and Geologic Field Observations <br />Apache Rocks and Box Canyon Mining Areas <br />July t2•t5. 2004 <br />The aecl`SS fOad IO methane drainage well sites MDW-14-09 and MD1V-IS-09 have been <br />reclaimed and closai. A lout traverse was not considered an eflicicnt use o1'time beamse the <br />subsidence cracks itt the unccrosolidutcd clays, soil, and alluvium would bc: covered up during <br />reclamation of the drill sites and access roads; and the cracks iu sandstone near the clitT had <br />remained the same during the visits in 2002 and 2003 (for details, sec: Figures I I and 12 of <br />the 2002 report and figures 5 and SA of the 2003 report). <br />L,ucanon I <br />Rockfall located in a massive sandstone cliff outcrop of the Ohio Creek btember of the <br />Mesuvcrdc Formation (Figure I ). The overview image shown as Figure I was taken liom a <br />point 2,2W feet south of the rockfall above the headgate entries of mined longwall panel IS on <br />the main drill hulr access road. <br />A slab of rock, ranging from a foot or two to as much as 5 feet thick. came Icwse along a <br />northeast-trending joint surface. The slab toppled along another joint surface, roughly <br />perpendicular to the first joint mentioned, then broke into Iargc angular boulders, and fell <br />onto the slope and West Flatiron access road below (Figure 2). <br />831.032.640 W nght W alar Englneera, Inc. Page 9 <br />September 2004 <br />Figure 1. Northward view of a rocklall (left center), that occurred in a Gdf outcrop of sandstone of (he <br />Ohio Creek Member of the Mesaverde FormaGOn. <br />