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Subsidence Field Observations <br />West Elk Mine <br />August 28 and 29, 2001 <br />3.2.3 Traverse F-F' <br />Traverse F-F' is along the old drill road from Apache Rocks to drill hole SO.W-3 in overburden <br />to the B-Seam ranging tom 1,350 to I,I50 feet thick. <br />• The only subsidence cracks observed were those above longwall panels 13 and 13-A at <br />Locations 7, 8 and 9, as described below. A recent desiccation crack was observed in a <br />large tank trap located about 500 feet north of SO.W-3. <br />3.2.4 Location 7 <br />Location 7 is at Location 18 of 2000 above the approximate center of mined-out longwall panel <br />13. <br />• The projected overburden thickness to the B-Seam is 1,150 feet thick. <br />• The cracks are much less visible, or are completely obliterated, when compared to their <br />appearance in 1999 and 2000. <br />• The cracks in these softer, friable sandstones tend to slough, fill and seal much faster <br />than the cracks in the harder, more durable sandstones at Apache Rocks. <br />3.2.5 Location 8 <br />Location 8 is above mined-out longwall panel 13 at Location 16 of 2000. <br />• The projected overburden thickness to the B-Seam is 1,300 feet. <br />• The cracks in the surficial material are mostly obliterated. <br />• The cracks in the friable sandstone are mostly in-filled and hard to distinguish, with the <br />exception of two cracks in durable sandstone that form a small graben (see Figure 4 of <br />the 2000 report). These cracks look similar to their appearance in 2000, except they <br />show some signs of aging. <br />631-032.560 Wright Water Engineers, Inc. Page 10 <br />September 2001 <br />