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Subsidence and Geologic Field Observations <br />Apache Rocks and Box Canyon Mining Areas <br />Julv 12-15, 2004 <br />4.0 OBSERVATIONS AND EVALUATIONS ALONG FIELD TRAVERSES AND AT <br />INDIVIDUAL LOCATIONS FROM JULY 12 THROUGH JULY 15 <br />4.1 Subsidence Observations and Evaluations on July 12, 2004 <br />4.1.1 Traverse A-A' <br />This vehicle traverse begins at the locked gate in Horse Gulch and ends at Twin Ponds. <br />• Traversed above the eastern portions of longwall panels 13 and 13A, above the portion of <br />longwall panels 17 and 16. All panel sections had been longwall mined. <br />• Weathered bedrock, and su~cial material (alluvium, colluvium and soil) and local bedrock <br />(sandstones, siltstones, and mudstones of the Barren Member of the Mesaverde Formation), <br />were encountered during the traverse. <br />• Overburden depth to the B Seam ranges from 1,100 to 1,250 feet. <br />• No subsidence features (cracks, bulges) were observed. <br />4.1.2 Traverse B-B' <br />Vehicle traverse that begins at Twin Ponds and ends at the fork in drill roads located above <br />projected headgate entries of un-mined longwall panel 24. <br />• Traversed above the approximate middle parts of mined longwall panels 14 and 15, thence <br />northwazd to the south edge of un-mined longwall pane124. <br />• Massive sandstones of the upper part of the Ohio Creek Member of the Mesaverde <br />Formation, in addition to colluvium and soil, were encountered in the traverse. <br />• Overburden depth to the B Seam ranges from 1,150 to 2,050 fee[. <br />831-032.640 Wright Water Engineers, Inc. Page 8 <br />September 2004 <br />