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Subsidence Field Observations <br />West Elk Mine <br />August 28 and 29, 2001 <br /> <br />3.1.2 Location 1 <br />Location 1 is about 1,000 feet north of the southernmost degasitication well at drill site RAV-]0 <br />near the northern edge of the mined-out part of longwall panel 14 (overburden thickness is 2,250 <br />feet). <br />• No cracks were observed in the sandstone or overlying silty claystone outcrops (see <br />video). <br />• One small crack, probably an open joint (see video), was observed on the cliff east of the <br />southern degasification site at drill site RAV-10. <br />3.1.3 Location 2 <br />Location 2 is at the southwestern point of West Flatiron where a large cliff outcrop of the Ohio <br />Creek sandstone occurs. <br />• The overburden thickness to the B-Seam is about 1,900 feet. <br />• The longwall face is presently located 1,500 feet east of Location 2. <br />• This is a baseline observation prior to mining (see video and Figures 2 and 3) to which <br />subsequent observations after the longwall face comes within the area of mining <br />influence will be compared. <br />Figure 2. Northward riew of Ohio Creek sandstone <br />"~, outcrop, which is outside the angle of draw. <br />831-032.560 <br />September 2001 <br />Wright Water Engineers, Inc. <br />Page 4 <br />