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West Elk Mine <br />subsidence. As such, the conservative approximate limit of the maximum predicted E-seam <br />angle -of -draw is 19 degrees. <br />To document subsidence features, MCC conducts visual surveys, and any necessary traditional <br />surveys, semiannually each year and provides the information in a written subsidence report by <br />the end of September and April each year. A summary of the visual observations and monitoring <br />is provided in first and fourth quarter letter reports to CDRMS and to the USFS. If any <br />mechanical response is detected during these visual inspections that is not consistent with what <br />has been previously observed, MCC will notify CDRMS within ten working days of our <br />observations. <br />The Spring and Fall reports of the visual surveys will include photographs to document any <br />subsidence features, including cracks, rockfalls, landslides, revegetation, and other relevant <br />features. A map will also be included that identifies the location of the photographer and the <br />aspect of the image for each photograph. An additional map will be prepared that identifies the <br />location and extent of the observed features. MCC will attempt to revisit previously identified <br />subsidence features to note any changes that have occurred since the previous visit. MCC will <br />also attempt to replicate the aspect of the photographs taken previously to document the <br />progression of subsidence and subsequent healing. The discussion of the field observations will <br />in particular address the development and healing of the subsidence features, utilizing the <br />photographic documentation. In addition, MCC will discuss baseline conditions observed in <br />areas prior to undermining. The report will document how the inspection was conducted, and <br />include such observations as weather and ground conditions. <br />In addition to performing the visual surveys, aerial or other type photos will be taken prior to <br />beginning mining in an area, periodically during mining, and after mining when subsidence is <br />complete to document landslides, rockfalls, vegetation, etc. over the areas being mined. This <br />documentation will provide a broader, more extensive view from which to associate or assess <br />landslide and other surface activity due to mining. <br />1 Veri ication and Accurac , o Predictions <br />In order to verify and demonstrate the accuracy of subsidence predictions, based on the results of <br />past subsidence observations in prior mining areas, MCC will implement the following <br />procedures to monitor Monument Dam prior to mining. The following procedures will be <br />implemented as soon as permitting allows, in order to account for seasonal precipitation changes. <br />1. Conduct annual aerial photo surveys of the landslides located north and south of the <br />reservoir, using the July 2004 photos as a baseline reference. Surveys will continue while <br />mining is occurring within panels LWE16 and LWE17. <br />2. Install, and measure, survey monuments strategically located on the dam and on the <br />north, south, and east edges of the reservoir to monitor any movement prior to, during, <br />and after mining in the area. During the monument surveys, conduct visual inspections <br />along the monument transects for surface cracks. Monitoring (surveying and inspections) <br />of stations in the Minnesota Reservoir area and across the crest of the Monument Dam <br />will be initiated at least one month prior to mining of Panel E12 and continue for two to <br />three months after mining is complete in the panel. MCC will initially survey the <br />2.05-117 Rev. 06/05- PRIO, 03/06- PRIG, 05/06- PRIO, 11/060- TRIO7, 04/07- TR108, 09/07- PR12, 02/08- PR12, 11/10- MR372: 10/20- MR-452; <br />12/20- TR149; 1221- TR150 <br />