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Fall 2017 Subsidence and Geologic Field Observations <br />South of Divide and Dry Fork Mining Areas <br />3.2 USFS Roads and Stock Pond Monitoring <br />Observations by MCC personnel of the USFS roads and stock ponds in the vicinity of active <br />mining activities have occurred for many years. Inspection forms from observations conducted <br />during the fall of 2017 are included with this report in Appendix B. <br />3.3 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 have been performed each year since 2004 using <br />the July 2004 photograph as a baseline reference. For brevity, Maps C-2 (September 2008), C-3 <br />(June 2009), C-4 (May 2010), C-5 (May 2011), C-6 (June 2012), C-7 (May 2013), C-8, (June <br />2014) and C-9 (June 2015) are not included herein but can be found in the previous fall reports. <br />Maps C-1, C-10 (June 2016) and C-11 (May 23, 2017) are provided in this report for comparative <br />purposes. <br />A comparison of the most recent image to that from 2004 finds no changes attributable to mining <br />activities. The only notable difference over time is in the area south of the south Monument Dam <br />abutment where a fall 2009 French drain installation occurred, as discussed in numerous previous <br />reports. A comparison of the two most recent images finds no discernable differences. <br />At the time of the May 2017 aerial photograph, E -seam longwall mining was complete on Panels <br />E1, E2, E3, E4, and E5 and about ninety percent (90%) complete on Panel E6 with mining <br />progressing from southeast to northwest. <br />3.4 U.S. Forest Service Water Resources Survey <br />MCC is required, as part of its permit, to monitor USFS water resources (i.e., reservoirs and <br />stock ponds). Appendix D of this report is the 2017 Water Resources Project Survey Report <br />generated for this purpose. <br />831-032.799 Wright Water Engineers, Inc. Page 8 <br />February 2018 <br />