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West Elk Mine <br /> <br />2.05-118 Rev. 06/05- PR10, 03/06- PR10, 05/06- PR10, 11/060- TR107, 04/07- TR108, 09/07- PR12, 02/08- PR12; 11/10- MR372; 10/20- MR-452; <br /> 12/20- TR149; 12/21- TR150, 1/24-TR152 <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 />monuments on the dam axis quarterly and then monthly when E-seam longwall mining is <br />occurring within one mile of the dam. The results of the surveys will be submitted in the <br />semi-annual subsidence reports. While mining is occurring within the angle of draw, <br />weekly inspections will be made of the dam for cracks or other potentially damaging <br />features and the inspection reports will be included with the semi-annual subsidence <br />reports. The monuments along the dam and reservoir basin will be resurveyed as soon as <br />possible if a seismic event occurs that exceeds the “threshold event” as described below. <br />If, during the inspections, cracks or other potentially damaging features are noted to be <br />occurring in the reservoir basin or dam structure, CDRMS, the Minnesota Reservoir <br />Company, SEO, USFS and other appropriate agencies will be notified by MCC <br />immediately and, depending on the severity of the damage, mining may cease until a new <br />mine plan can be approved and mitigation performed. <br />In addition to the survey monuments on the dam, in cooperation with Minnesota Canal & <br />Reservoir Company, MCC will measure the water level in the piezometers installed in the <br />crest of the dam on monthly basis, April through October, when accessible. The water <br />level measurements will be included in the semi-annual subsidence reports. <br />3. Mining of panels LWE16 and LWE17 will be from the south to the north. Monitoring <br />(surveying) of stations to the south of the Minnesota Reservoir and across the crest of the <br />Monument Dam will be re-initiated at least one month prior to mining of panels LWE16 <br />and LWE17 and continue for two to three months after mining is complete in the panels. <br />MCC will initially survey the monuments on the dam axis quarterly and then monthly <br />when E-seam longwall mining is occurring within one mile of the dam. The results of <br />the surveys will be submitted in the semi-annual subsidence reports. While mining is <br />occurring within the angle of draw, weekly inspections will be made of the dam for <br />cracks or other potentially damaging features and the inspection reports will be included <br />with the semi-annual subsidence. <br /> reports. The monuments along the dam and reservoir basin will be resurveyed as soon as <br />possible if a seismic event occurs that exceeds the “threshold event” as described below. <br />If, during the inspections, cracks or other potentially damaging features are noted to be <br />occurring in the reservoir basin or dam structure, CDRMS, the Minnesota Reservoir <br />Company, SEO, USFS and other appropriate agencies will be notified by MCC <br />immediately and, depending on the severity of the damage, mining may cease until a new <br />mine plan can be approved and mitigation performed. <br />4. The landslide feature that is located on and is part of the left (south) abutment will be <br />monitored for movement when mining is within the angle of draw. MCC will install <br />survey monuments within the landslide on the hill to the south of the dam and within the <br />toe of the landslide. These monuments will be surveyed monthly, when accessible,