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<br />62 <br /> <br />to depths downstream) is sufficient to prevent subsidence fractures from capturing <br />significant volumes of stream flows. Based on this information, mining in the Dry <br />Fork lease area does not appear to have the potential to cause material damage to <br />Deep Creek. <br /> <br /> 3. Until 1999, subsidence monitoring at the West Elk Mine was accomplished using <br />conventional survey methods of a monument grid. The monitoring of MCC’s <br />subsidence grid established the amount of subsidence that occurs over a longwall <br />panel, when and where it occurs and when it is complete. MCC was approved to <br />replace the monument survey with a visual inspection of the ground over areas that <br />have been undermined to document any disturbance. A survey is done prior to <br />mining and to areas where effects of subsidence were previously noted in order to <br />monitor the healing of cracks. Given the heavy snow cover and inaccessibility of <br />most of the affected area, MCC conducts the surveys during the summer of each year <br />and reports the results by the end of September. Any mechanical response detected <br />during these surveys that is not consistent with previous observations will be reported <br />to the Division within ten working days of the survey. <br /> <br />Due to the extremely steep topography and dense vegetative cover of the West <br />Flatiron area, MCC has proposed a subsidence monitoring program, in accordance <br />with Rule 2.05.6(6)(c), designed to concentrate on the landslide areas nearest <br />Highway 133. MCC will drive steel rods vertically into the old landslide body and <br />monitor these rods to assess any movement. <br /> <br />Section 2.05.6(6) of the permit application specifies proposed subsidence monitoring <br />locations, frequencies, and methods for the South of Divide area and the perennial <br />portion of Sylvester Gulch. Methods include surveying monuments, aerial <br />photography, surface water flow measurements, piezometer water level <br />measurements, and visual inspections. The monitoring frequency for each structure <br />or feature is designed to span the pre-subsidence to post-subsidence time period. <br /> <br />XVI. Concurrent Surface and Underground Mining <br /> <br /> 1. This section does not apply to the West Elk Mine.