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2005 Subsidence and Geologic Field Observations <br />Box Canyon, West Flabron, Apacho Rocks, <br />and South of Divido Mining Areas <br />4.3.1 Location 4 <br />Location 4, which marks the ridge loe;ation of a linear feature that N•as observed from the north <br />side of the Nonh Fork in July 2004, was viewed from cliff outcrop of the upper sandstone of <br />Ohio Creek Member at point B. <br />The northwest-trending lineament was mapped from a stereo pair of high-resolution photo <br />images (Map I ). No fractures were observed from point B. A 100-foot cliff blocked further <br />travel to location 4. Irregular, branching. and diverging dcsiccauon cracks'/. to'/~ inch wide <br />were locally ohscrvcd on the road and trail. <br />4.4 Traverse C-C' <br />Travcrsc C-C' rn?sscd Intm Ixnm B of traverse l3-B' ,.xtth~~ard fu a fork in the drill road at <br />MDW'_3-05. Soils were primarily light gray, light brown to reddish gray and rolluvium (clay <br />and silt) of the Wasatch and Ohio Creek Fonrtatiuns. <br />This Iravcnc was above un-mined longwall panels 19, 20, 21 and 23 and mined longwall panel <br />22. The overburden depth to the B-Scum of traverse averages atwut 2,250 (eet. <br />4.4.1 Location 5 <br />Location 5 is viewed and photographed fmm an uhscnation point along Travcrsc C-C' that <br />afforded the best view. This site of a rockfall and landslide was not present in 2003 (Uunrud <br />2003 ). <br />Location 5 is above the un-mined tailgate road pillars of mined longwall panel 22-an area of <br />maximum predicted tensile ,train. Ovefiurden depth to the B-Seam is about 1,825 feet. <br />The mass-gravity sequence of cvcros likely im~olvcd the following praesscs: I) large slabs of <br />rtx:k became detached along fracture and joints of the upper, massive sandstone Icdge of the Ohio <br />Creek Formation of the Mesavcrdc Formation: 2) the massive pieces of nx:k toppled, I-ell, and <br />broke up as they rolled downslopc: and 3) formed a slide in the run-out zone below the cliff <br />831-032.710 Wright Wator Engineers, Inc. Page 15 <br />Novembor 2005 <br />