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Spring 2014 Subsidence and Geologic Field Observations <br />South of Divide and Dry Fork Mining Areas (E -Seam) <br />maximum angle of draw is an appropriate value for use in the SOD and Dry Fork mining areas <br />relative to E -seam mining. A memorandum outlining this analysis and conclusion can be found <br />in Appendix B of this report along with Map B -1 showing the 120 survey monuments associated <br />with the subsidence monitoring grid. <br />MCC has been collecting data from numerous monitoring locations in and around Minnesota <br />Reservoir, Monument Dam and the genefal Dry Fork area for years. As stated above, an effort has <br />been made to reduce the size of thes$ semi - annual reports and as such, once a monitoring <br />commitment has been met the data is removed from future reports. To date, removed data include <br />survey data for the Dry Fork Channel, the Lower Cow Camp and other points that have shown no <br />substantial subsidence in eight consecutive quarters (see previous reports for this earlier <br />subsidence data). <br />Ongoing monitoring by MCC personnel includes the Monument Dam and Minnesota Reservoir <br />area as well as U.S. Forest Service (USFS) roads and stock ponds. Survey data and inspection <br />forms for these areas are provided in Appendix C and D respectively. Data and discussions <br />associated with Section 2.1 and Appendices C -D are provided by MCC and are contained in this <br />WWE report for convenience. <br />2.1 Monument Dam /Minnesota Reservoir Monitoring Data <br />Beginning in 2006, numerous monitoring stations were established on Monument Dam and at <br />strategic locations around Minnesota Reservoir as a means to collect baseline information about <br />water levels and potential surface /subsurface movement. Monitoring locations include three <br />historic standpipe piezometers, four baring locations each with three nested piezometers, two <br />inclinometer locations (one on the dano and one in the landslide area south of the dam), and <br />numerous survey mirrors for evaluation of surface movement on and near the dam. Many of these <br />locations have been monitored monthly from July 2006, while others were added to the monitoring <br />network during 2007 and 2008. Beginning in the 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 State Engineer's Office <br />(SEO). MCC retained monitoring and reporting responsibilities for the land survey stations. Data <br />831 - 032.795 Wright Water Engineers, Inc. Page 4 <br />September 2014 <br />