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Fall 2014 Subsidence and Geologic Field Observations <br />South of Divide and Dry Fork Mining Areas <br />network during 2007 and 2008. Beginning in spring 2010, the Minnesota Canal and Reservoir <br />Company took over the monitoring and reporting responsibilities for the piezometers and <br />inclinometers on Monument Dam per their agreement with MCC and the Colorado State <br />Engineer's Office (SEO). MCC retained monitoring and reporting responsibilities for the land <br />survey stations. Data collected from various monitoring locations on the Monument Dam <br />(including Dam Inspection Forms) are provided in Appendix B. <br />As discussed in previous reports, the Minnesota Reservoir Robotic Total Station (RTS) became <br />completely inoperable in 2011 and could not be repaired after numerous attempts. In lieu of the <br />RTS, quarterly land surveys of the monuments (increased to monthly when mining is within one <br />mile of the dam) are completed. A summary of both average height and longitudinal displacement <br />data obtained from spring 2014 to fall 2014 is provided in Table 1 as Appendix B. <br />4.2 Monument Dam /Minnesota Reservoir Aerial Photograph Comparison <br />Each year, MCC performs an aerial photographic survey of the landslides located north and south <br />of Minnesota Reservoir. Annual comparisons are performed using July 2004 photographs as a <br />baseline reference. Appendix C of this report includes the July 2004 baseline photograph (Map <br />C -1), as well as a photograph of the same area taken in June 2012 (Map C -6), May 2013 (Map C- <br />7), and June 2014 (Map C -8). For brevity, Maps C -2 (September 2008), C -3 (June 2009), C -4 <br />(May 2010), C -5 (May 2011), and C -6 (June 2012) are not included herein but can be found in the <br />previous fall reports. Maps C -1, C -7, and C -8 are provided in this report for comparative purposes. <br />A comparison of the most recent image with one flown in May 2013 finds no discernable change. <br />A comparison to an image from a July 2004 flight reveals a continued scar from where a french <br />drain was installed south of the Monument Dam south abutment in early fall 2009 to remove water <br />from the upper end of the existing slide complex. <br />As of the time of the 2014 aerial photograph (June), E -seam longwall mining was complete on <br />Panels E1, E2, E3, and E4 and approximately 10 percent complete on Panel E5 with mining <br />progressing from southeast to northwest. <br />831 - 032.796 Wright Water Engineers, Inc. Page 23 <br />March 2015 <br />