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West Elk Mine <br /> <br />2.05-121 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, 2/25-MR486 <br />addition to the surveying, changes in the ditch caused by subsidence will be detected by visually <br />inspecting the ditch on a weekly basis while active longwall mining is within 1000 feet of the <br />ditch. MCC will repair any mining-caused damage found during the monitoring or during visual <br />inspections, in accordance with the agreement between MCC and the Minnesota Canal and <br />Reservoir Company. If mining activity disrupts flow in the ditch, MCC will apply methods set <br />out in the subsidence mitigation plan or injured parties will be compensated with water resources <br />that are owned by MCC per its adjudicated water augmentation plan. These water resources are <br />identified in Exhibit 52. <br /> <br /> <br />Anticipated Effects – 2.05.6 (6)(f)(iii)(A) <br />Long-term impacts on the surface are predicted to be minimal above the mined longwall panels. <br />The few surface cracks over the mining panels that may occur are expected to close once the <br />longwall face moves past the surface area of influence. Surface cracks present above the chain or <br />barrier pillars or mine boundaries may remain open where permanent tensile strains remain after <br />mining is completed. However, at least several hundred feet of unfractured rock will typically <br />exist between any mine-induced surface fractures and the upper part of any mine-induced fractures <br />above the caved zone in the mining panels. Therefore, from a practical standpoint, no <br />interconnection between the surface fractures and the mine workings is anticipated. Again, under <br />a worst case scenario, if a surface fracture were to occur concurrently within an area controlled by <br />faults or bedrock lineaments, there could be interconnection between adjacent sandstones. <br />However, even under these conditions, the fractures would most likely not extend through the <br />claystones and shales present in the overburden. <br />Monument Dam and Minnesota Reservoir are located outside of the angle of mining influence of <br />the eleven longwall panels (panels LWE1-8, SST1-4, LWE10-12 and LWE15-17) within the South <br />of Divide mining area (see Map 51). The northern portions of panels LWE16 and LWE17, which <br />are nearest to the reservoir, are located several hundred feet away. The angle of draw to this <br />nearest area of mining is 79º. The angle is much greater than the maximum of 19º projected for <br />the SOD mining area. This means that Minnesota Reservoir will not be affected by longwall <br />mining in projected panels LWE16 and LWE17. <br />Reduction Measures (Underground) - 2.05.6 (6)(f)(iii)(B)(I-III) <br />Underground measures that may be taken to reduce surface strains above the chain pillars could <br />include, but are not limited to; (1) Designing the pillars to yield and crush after mining (thus <br />minimizing humps in the subsidence profile), and/or (2) Planning a rapid and uniform mining rate. <br />Any plans in order to reduce chain pillar dimensions to reduce subsidence impacts must, of course, <br />be balanced with health and safety conditions in the mine. Plans for a rapid and uniform mining <br />rate are affected by market demands (or lack there of) for constant, high volumes of coal. MCC <br />will notify CDRMS if plans that may affect the subsidence profile are implemented. <br />As discussed in previously in section 2.05.6, Wright Water Engineers has completed detailed <br />subsidence modelling and evaluations from longwall mining in the SOD, Southern Panels, Apache <br />Rocks West, Dry Fork and Sunset Trail mining areas and provided recommendations for longwall <br />mining heights and cover depths. MCC will adhere those recommendations as detailed in Exhibit