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6. Monitoring seismicity at a seismic station previously installed on <br />Monument Dam and to be installed in selected E-seam panels, <br />7. Removing any significant sediment accumulation from the reservoir <br />caused by mining, <br />8. Constructing a stability berm and buttress at the dam, and making other <br />modifications to restore the dam to a 1.5 static safety factor and to enable <br />the dam to withstand the predicted maximum seismic event from mining <br />in the South of Divide area of 2.3 on the Richter scale and peak ground <br />acceleration of 0.16 g, <br />9. Surveying monuments on the dam within two days of a seismic event that <br />exceeds 0.16 g, and if the integrity of the dam or reservoir appears <br />threatened, immediately notifying the Division, the Minnesota Reservoir <br />Company, the U.S. Forest Service, the Office of the State Engineer, and <br />other appropriate agencies, <br />10. Submitting periodic reports of monitoring data to the Division, and <br />11. Replacing, repairing, and otherwise restoring the dam and structures <br />downstream or purchasing insurance policies addressing downstream <br />damage that will be in effect at the time of longwall mining, should <br />catastrophic failure of the dam occur as a result ofmine-induced impacts. <br />12. Augmenting surface water supplies lost due to subsidence according to the <br />Augmentation Plan contained in Exhibit 52 of the permit application. <br />To address concerns raised by the Division of Water Resources, Office of the <br />State Engineer, Colorado Department of Natural Resources in DWR's letter of <br />Apri121, 2006 to the Division of Reclamation, Mining and Safety, the <br />Division attached Stipulations Nos. 74, 75, and 76 to the decision for PR-10. <br />As of early 2008, the West Elk Mine was progressing toward completing the <br />mitigation measures listed above (as approved in TR-108), and the owner of <br />the dam and reservoir had received conditional approval for the use of these <br />structures in 2008 from the Office of the State Engineer (letter dated February <br />29, 2008 to Minnesota Canal and Reservoir Co.). <br />Minnesota Creek Ditch Rider's Cabin -MCC predicts the cabin will not be <br />affected by mining because the nearest longwall panel (panel E6) will be at a <br />depth of 1,200 feet, approximately 800 feet away from the cabin. The <br />calculated angle of contact between the panel and the cabin will be <br />approximately 40 degrees, significantly more than the 20-degree predicted <br />maximum angle of draw in the Dry Fork lease area. <br />49 <br />