2001-07-16_GENERAL DOCUMENTS - C1980007

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MCC has extended the subsidence monitoring network to include Jumbo Mountain and the Apache Rocks revision areas. The location of the monuments is shown on an Addendum to Exhibit 60. In addition, MCC will establish and survey an aerial photo control point grid, complete aerial photography of the mine plan area, and then use photogrammetric methods to measure subsidence. MCC will verify the effectiveness of this methods by continuing the conventional survey of the existing grid and of the decreed water rights on Jumbo Mountain to be under mined. If aerial photogrammetry is successful, MCC will then submit a revision to eliminate surveying by traditional methods. In addition to providing subsidence survey data, the aerial photos from the fall photogrammetric survey will be utilized to map the numerous, small landslide bodies on the north face of Jumbo Mountain. This mapping will provide a broader, more extensive view from which to associate or assess landslide activity due to mining. An evaluation of the F Seam subsidence monitoring program is provided in Exhibit 60 (Volume 13). The evaluation includes an analysis of the survey data obtained from the F Seam monitoring network to date, correlation with industry subsidence protection models, and summary of subsidence parameters observed for the F Seam. Predictions of subsidence from proposed mining in the B Seam are included and are based on data and evaluations of the F Seam subsidence and current industry data. XVI. Concurrent Surface and Underground Mining 1. This section does not apply to the West Elk Mine. XVII. Operations on Alluvial Valley Floors The applicant has performed a detailed reconnaissance investigation for alluvial valley floors. During the investigation, the applicant identified several areas within or adjacent to the mine plan area which may meet the geomorphic criteria of alluvial valley floors. Alluvial deposits were identified along Minnesota Creek, the Dry Fork of Minnesota Creek, Sylvester Gulch, and the North Fork of the Gunnison River. Two of these areas, Minnesota Creek and the Dry Fork of Minnesota Creek, although geographically adjacent to the permit area, are not hydrologically adjacent to the activities approved in the permit. Both a surface water divide and a groundwater divide separate these areas from mining activities. However, since part of the Minnesota Creek drainage lies within the 40-year life-of-mine lease boundary and may be affected by future mining, it will be considered in this determination. An area identified in the permit document which may meet the geomorphic criteria of alluvial valley floors is located along Sylvester Gulch. The lower refuse pile is being 56