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Subsidence and Geologic Field Observations <br />Apache Rocks and Box Canyon Mining Areas <br />July 12-15, 2004 <br />• Traversed above the northeastern part of mined longwall panel 16, across the eastern part of <br />mined longwall panel I5, the eastern part of mined longwall panel 16, and the tail gate entries <br />of mined longwall panel 17. <br />• Colluvium, locally thick soil, and weathered bedrock were encountered on the traverse. <br />• Overbtuden depth to the B Seam ranges from 1,100 to 1,400 feet. <br />• No subsidence features were observed. <br />4.2.3 Traverse I-I' <br />This foot traverse begins at the seep/spring located at the first west-trending draw located south <br />of West Flatiron and ends at the Deep Creek crossing 1,000 feet south of the headgate entries of <br />' mined longwall panel 17-a distance of approximately 4,500 feet. <br />' Traveled above the headgate entries of the eastern part of longwall panel 16, thence above the <br />mined-out part of longwall panel 17 and southwazd on the trail beyond the azea of mining <br />' influence. <br />• Material traversed was the Deep Creek alluvium. The material ranges from coarse to fine <br />' gravel, fine gravel and sand, and also clay and soil. <br />• Traveled above the eastem parts of mined-out longwall panels 15, 16, and 17. <br />• Overburden depth to the B Seam ranges from about 1,050 to 1,100 feet. <br />• No subsidence features were observed. No subsidence features have been observed in the <br />Deep Creek alluvial valley since longwall panels 14 through 17 were mined. <br />• Based on the subsidence development curve concept for the West Elk mining area, <br />subsidence is now complete, and there is no reason to conduct more traverses in the azea. <br />831-032.640 Wright Water Engineers, Inc. Page 20 <br />September 2004 <br />