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-58- frequency. In future permit periods, when renewable resource lands and structures may be undermined, pre- and post-mining inspections of structures will be incorporated. The applicant also commits to daily inspection of the Steven's Gulch road, in order to protect the public. Existing monitoring stations No. 1 through No. 27 comprise a wide-spaced monument grid on approximately 1300' centers east-west and 2600' centers north-south. These monuments provide general observations regarding the magnitude of vertical subsidence occurring. Additional wide-spaced monuments No. 70 through No. 87 will be installed above proposed mine workings adjoining the old east portals. Additional monuments No. 90, 92 8 93 will be installed above the proposed underground workings adjoining the new West Portals. A number of high-resolution, closely-spaced subsidence monuments have been installed in sites selected throughout the existing permit area. Monitoring stations No. 201 through No. 224 are installed above projected fault traces in an attempt to discern the effects of differential subsidence between alternating fault blocks. Stations No. 42 through No. 51 are located in areas of thick overburden. Stations No. 28 through 41. in contrast, have been installed above overburden thicknesses considered typical throughout the permit area. Depending upon rates of mining advance and mine production, data from these high-resolution subsidence monument networks should begin to become available in 1985. High-resolution subsidence data, with which to define the angle of draw, will be generated during the next few years. Data collected from these monument grids will allow verification, or support redesign, of the subsidence control plans proposed by CWI for implementation in the future. XXII. SPECIAL CATEGORIES OF MINING OTHER THAN AVF AND PRIME FARMLAND 2.06, .22, .2 .2 .2 . This section applies to the following categories of mining: Experimental Practices Mining Mountaintop Removal Mining Steep Slope Mining Concurrent Surface and Underground Mining Auger Mining In-Situ Processing Variances from Approximate Original Contour Orchard Valley mine has obtained a variance from the requirement for restoration of affected lands to their approximate original contour in accordance with Rules 2.06.5 and 4.27. The variance was granted under the 1981 permit and is hereby reissued. The variance applies to the mine benches only and was granted because it was demonstrated that backfilling the benches to A.O.C. on such a steep slope would not achieve the required slope stability safety factor of 1.3 (see Volume 10, Stability Analysis, for a complete discussion).