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831 - 032.794 <br />April 2013 <br />Fall 2012 Subsidence and Geologic Field Observations <br />Box Canyon, Apache Rocks, and South of Divide Mining Areas <br />Department of Transportation relative to impacts on Colorado Highway 133 (Hwy 133). <br />Observations from this location show the relatively recent slide that occurred adjacent to the <br />Refuse Pile Expansion area, located immediately south of Hwy 133 and east of the main <br />entrance to the West Elk Mine. This is an area identified with a very high rockfall /landslide <br />potential according to Map 3 of this, and previous, reports. This slide occurred well after B- <br />seam longwall mining occurred in this vicinity. A comparison of photographs obtained during <br />fall 2011 and fall 2012 finds no significant changes. <br />In the SOD mining area, subsidence related cracks were observed and reported during the spring <br />2012 field visit along Traverse K -K" and Traverse K 1 -K l ' in the areas south and east of the Cow <br />Camp along U.S. Forest Service (USFS) Road 711 (Dry Fork Road) (Map 2). At the time of our <br />fall 2012 field traverses, the previously observed subsidence cracks had healed and sealed <br />substantially. In some instances, the cracks were nearly unrecognizable with only minor <br />evidence remaining. Additional baseline observations were made of MDW pads above portions <br />of E -seam Longwall Panels E4 in the SOD mining area with several showing differential <br />settlement cracks in the largest fill areas of the pad (due to ongoing settlement of the fill <br />material). Details and examples of this phenomenon can be found in numerous previous reports. <br />Numerous subsidence- related cracks were observed in the areas along Traverse P -P' above the <br />current longwall face and areas recently mined. These areas are beneath E -seam Longwall Panel <br />E3 between the E3 -12 and E3 -17.5 MDW pads (Map 2). All observed subsidence - related <br />features were located immediately above the mining activities or within the projected draw <br />angle. Additional details regarding the SOD mining area observations can be found in Section <br />3.0 of this report. <br />Wright Water Engineers, Inc. Page 4 <br />