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Spring 2009 Subsidence and Geologic Field Observations <br />Box Canyon, Apache Rocks, and South of Divide Mining Areas <br />• 5.8.3 Location 9 <br />This location (an annual observation location) provides a good, close -up view of the headscarp of <br />the first eastern drainage of Sylvester Gulch that terminates on West Flatiron. The view from <br />this location is of the upper part of the Ohio Creek Member of the Mesaverde Formation (Figure <br />32). This very high rockfall potential location (see Map 3), is located at the approximate <br />midpoint of mined Longwall Panel 22 and is 2,200 feet above the elevation of the B -seam. <br />• <br />Figure 32. Spring 2009 southward view of the upper part of the active rockfalUlandslide scarp <br />located at the head of the first east side canyon of Sylvester Gulch above mined Longwell. Panel <br />22. <br />Previous observations from this location show that the rockfall /landslide activity increased <br />significantly after Longwall Panel 22 was mined. However, photographs taken in subsequent <br />years show little change other than seasonal differences. This headscarp area is best viewed from <br />the west side of Sylvester Gulch (Photographic Observation Points 4 and 5, Map 1). <br />5.8.4 Photographic Observation Point 4 <br />Photographic Observation Point 4 (Map 1) was established in July 2003 to provide an overview <br />of the active rockfall /landslide area at the head of the first eastern drainage of Sylvester Gulch <br />• that terminates on West Flatiron (Location 9 of this report). Photographs taken from this location <br />831- 032.791 Wright Water Engineer, Inc. Page 44 <br />November 2009 <br />