2022-09-29_PERMIT FILE - C1980007A (3)

Home Browse Search

West Elk Mine subsidence. As such, the conservative approximate limit of the maximum predicted E-seam angle -of -draw is 19 degrees. Water and Methane Observations of the north and west flanks of Mt. Gunnison during an October 1996 field trip, revealed numerous talus and rock glacier deposits that occur in the valleys and lower part of this intrusive body. Snow melt and rain can easily infiltrate these deposits, which may eventually enter any permeable rocks, faults, fractures, and joints near the mountain. Coal beds and rocks in the deformed zone around Mt. Gunnison might also contain increased methane where the coal is metamorphosed to a higher rank by the intrusive body. Great quantities of water and methane may therefore be expected as coal is mined closer to Mt. Gunnison. Effects Of Subsidence And Mine -Induced Seismic Activity On Man -Made Structures And Renewable Resources Man-made structures and renewable resources in the South of Divide mining area basically consist of 1) A dam and reservoir (Monument Dam - Minnesota Reservoir), 2) stock watering ponds, 3) streams (primarily Dry Fork and the upper part of Lick Creek), 4) roads, and 5) local cabins. Minnesota Reservoir, the ponds, and the Deep Creek Ditch diversion to Dry Fork serve the dual purpose of being both man-made structures and containment structures for the valuable water resources in the area. Based on past subsidence observations in the Jumbo Mountain, Apache Rocks, and Box Canyon mining areas during the last nine years, the following information is considered appropriate for the South of Divide mining area. Monument Dam - Minnesota Reservoir Monument Dam - Minnesota Reservoir, which provides storage water primarily for irrigation, is located between two landslides —one beginning at the north shore and the other beginning at the south shore. As explained above, landslide movement on Jumbo Mountain occurred during unusually wet periods before mining began, during mining, and after mining and subsidence was complete. The conclusions were that landslide movement occurs in response to ground saturation and is not noticeably affected by subsidence and seismic activity produced by longwall mining beneath, or near, landslide areas. The landslides north and south of Minnesota Reservoir occur in surficial material (loose rock, gravel, sand, silt, clay, and soil) and local bedrock outcrops. The author therefore expects that the mining of longwall panels LWE16 and LWE17 will not noticeably affect the large landslide south of Minnesota Reservoir. Mining of the longwall mining panels in the South of Divide mining area did not affect Minnesota Reservoir. The reservoir is located outside the area of mining influence, using the most conservative angle of draw. Measured ground subsidence nor seismicity caused by longwall mining affected Monument Dam and Minnesota Reservoir. 2.05-111 Rev. 06105- PRIG, 03106- PRIG, 05106- PRIO, I11060- TRI07, 04107- TRI08, 09/07- PR12, 02108- PR12111/10- AIR372; 10120- �IIR-452; 12120- TR149; 12121- TR150