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II <br />II <br />Subsidence Field Observations <br />West Elk Mine <br />July 22-24, 2003 <br />' 4.2 Subsidence Observations and Evaluations for July 23, 2003 <br />4.2.1 Traverse F-F' <br />Traversed from fork in drill roads northeast of Twin Ponds to another fork in the drill roads <br />located at the head of the first west fork of Deep Creek located south of West Flatiron. <br />• Traversed above the southernmost part of the middle of mined-out longwall Panel 14, across <br />the middle of mined-out longwall Panel 15, and to the northernmost part of mined-out <br />longwall Panel 16. <br />• Fractured and weathered bedrock, colluvium, and soil were encountered on the traverse. <br />• Overburden depth to the B-Seam ranges from 1,500 to 1,600 feet. <br />• Most of the cracks encountered last year appeared to be caused by construction activities. <br />Last yeaz on this traverse, it appeared that roughly 75 percent of the cracks were caused by <br />construction activities and perhaps 25 percent may have been caused by mining. This year <br />the cracks appeared to be neazly all related to construction activities. <br />• Some desiccation cracks were observed in the weathered clay and colluvium. <br />4.2.2 Traverse G-G' <br />Traverse G-G' starts at a fork in two drill roads at Point F' and ends at operating Methane <br />Drainage Well MDW-17-03. <br />• Traveled mostly above mined-out longwall Panel 16 thence above the gate road entries, <br />consisting of three rows of rigid-pillars located between mined-out longwall Panels 16 <br />and 17. <br />• Traversed in mostly thick surficial material-thick dark reddish to brownish to gray soil- <br />and a few local outcrops of sandstone and shale. <br />831-032.610 Wright Water Engineers, Inc. Page 19 <br />' September 2003 <br />