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Subsidence and Geologic Field Observations <br />Apache Rocks and Box Canyon Mining Areas <br />July 12-15, 2004 <br />• Traversed through mostly weathered bedrock, colluvium, and soil of the Wasatch Formation <br />and the Ohio Creek Member of the Mesaverde Formation. <br />• Overburden thickness to the B Seam is about 2,200 feet. <br />• No new subsidence-related features were observed. <br />4.1.6 Traverse F-F' <br />Foot traverse that begins at methane drainage well site MDW-22-03 and ends at proposed <br />methane drainage well site MDW-20-O1 on the north point of West Flatiron. <br />• Traversed above the tailgate entries of mined longwall panel 22 and un-mined longwall <br />panels 21, 20, and 19. <br />• Traversed above weathered bedrock, colluvium, and soil, and local sandstone outcrops of the <br />Wasatch Formation and the Ohio Creek Member of the Mesaverde Formation. <br />• Overburden depth to the B Seam is about 2,200 feet. <br />' No subsidence features were observed, although the first part of traverse (roughly 800 to <br />1,000 feet) was within the area of influence of three rows of rigid pillars in the tail gate <br />entries of mined longwall pane122-an area of maximum tilt and strain. <br />Location 4: <br />Point is located near the east tim of West Flatiron at the top of the Ohio Creek Member of the <br />Mesaverde Formation (Figure 6). <br />• This point is located at the approximate south and west boundary between the Box Canyon <br />mining area to the west and the West Flatiron Lease (COC 67011) to the east. The left and <br />bottom edges of image mark the approximate west and south boundaries of the West Flatiron <br />Lease, respectively. <br />831-032.640 Wright Water Engineers, Inc. Page 15 <br />September 2004 <br />