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Leigh Simmons <br />Page 2 <br />November 12, 2015 <br />Rule 2.05.6(6)(e)(iii) —The West Elk Permit contains a detailed description of the measures to be <br />taken to prevent subsidence from causing material damage or lessening the value or reasonably <br />foreseeable use of the surface. <br />Rule 2.05.6(6)(d)(i) — The subsidence monitoring program for the West Elk Mine accurately <br />predicts the effects of subsidence within and adjacent to the permit area. <br />The subsidence monitoring reports record data and correlate the data to previous reports. The <br />monitoring plan includes data from the visual inspection of traverses, ponds, Forest Service roads/ponds <br />and surveys of the Monument Dam/Hillside South of Minnesota Creek Road. There has been no <br />significant or long term adverse effects to the permit area or adjacent areas. Subsidence cracks in the <br />mining area are influenced by the material in which they occur in. The majority of the cracks are in <br />alluvial or colluvial deposits. These cracks weather rapidly and are significantly reduced between when <br />they are identified and the following survey. Subsidence cracks that are identifiable over multiple years <br />generally occur in sandstone lenses that are at a shallow depth below a drill pad, access road or at an <br />outcrop. Typically the subsidence cracks in the alluvial and colluvial deposits will weather by rounding of <br />the edges and sediment infilling the crack. Rounding of the edges will widen the crack on the surface <br />but not to depth. Cracks in sandstone layers will weather in a similar way to those in the alluvial and <br />colluvial materials; however, they will take considerably longer to complete this process and the width <br />of the cracks will remain constant. Differential Settlement of fill materials is commonly exacerbated by <br />mining activities at the West Elk Mine. These cracks initially form due to gravity and not subsidence. <br />When mining occurs underneath these areas, the cracks become exaggerated. Fill -slopes on pads and <br />roads frequently show this type of subsidence related activity. There are a few noted cut -slopes on drill <br />pads that have had differential settlement occur on them. These cracks weather similar to subsidence <br />cracks in alluvial and colluvial material. <br />Landslides and rockfalls are closely monitored in the West Elk Permit Area. Photographs are taken <br />during the semi-annual surveys of areas identified as a landslide or rockfall areas and potential landslide <br />or rockfall areas. The photos are included in the report if there is noticeable movement between one <br />photograph and another. The climate seems to have more of an impact on landslide and rockfall areas <br />than the mining activities. When wet seasons or large storm events occur the area is more susceptible <br />to movement than when the area is undermined. Evidence in the reports has been documented that <br />mining will progress under an area designated as a potential landslide or rockfall area and no movement <br />will occur. Movement has occurred after a particularly wet season or a large precipitation event. The <br />SOD and Dry Fork mining areas have a smaller potential for landslides and rockfalls to occur due to the <br />topography. These areas have few cliffs and steep slopes when compared to the mining areas in the <br />Apache Rocks and Box Canyon. In 2009 a French Drain was constructed on the south side of Minnesota <br />Creek Road, which is prone to landslide activity. The French Drain removes water from the landslide <br />area to prevent the movement of material into Minnesota Reservoir or impact the dam. No mining has <br />