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West Etk Mine <br />• to note any changes that have occurred since the previous visit. MCC will also attempt to <br />replicate the aspect of the photographs taken previously to document the progression of <br />subsidence and subsequent healing. The discussion of the field observations will in particulaz <br />address the development and healing of the subsidence features, utilizing the photographic <br />documentation. In addition, MCC will discuss baseline conditions observed in azeas prior to <br />undermining. The report will document how the inspection was conducted, and include such <br />observations as weather and ground conditions. <br />In addition to performing the visual surveys, aerial or other type photos will be taken prior to <br />beginning mining in an azea, periodically during mining, and after mining when subsidence is <br />complete to document landslides, rockfalls, vegetation, etc. over the areas being mined. This <br />documentation will provide a broader, more extensive view from which to associate or assess <br />landslide and other surface activity due to mining. <br />For the original F Seam and B Seam monitoring program, conventional ground surveying <br />techniques were applied for surveying the former monument grid, as shown on Map 29. The <br />surveys were designed to achieve horizontal accuracy's complying with the U.S. Department of <br />Commerce's "Second order, Class II" surveying standazds, and vertical accuracy's no less than 0.2 <br />feet. Grids were surveyed twice prior to the initiation of subsidence. A minimum of six <br />triangulation benchmark monuments outside the azea of anticipated subsidence effects were selected <br />and established. Monitoring of the grid was discontinued in 1999. Subsidence monitoring reports <br />are submitted on an annual basis, due by September 30 of each year. Aerial photos taken will be <br />• maintained at West Elk Mine. <br />If it is deemed necessary to check projected subsidence values for the South of Divide mining azea <br />described in Exhibit 60B, a single subsidence monitoring station could be installed along Dry Fork <br />above projected longwall Panel E3 neaz WCC-1 (overburden thickness of about 750 feet). This <br />station would need to be monitored every few days to weekly, when the retreating mining face <br />moves to within about 350 feet (horizontal distance) of the subsidence monitoring station and until <br />the mining face is 350 to 500 feet beyond the monitoring station. <br />Monitoring Frequency- 2.05.6 (6)(b)(1)(D,E & F) <br />The subsidence monitoring program will continue to be performed annually and reported to the <br />CDMG annually, as well. <br />Subsidence Control Plan - 2.05.6 (6)(blliiil(Bl. (6)(d)(i&ii), (6)(e)(iv) & (6)(B(i-viii <br />Description of Mining Methods - 2.05.6 (6)(~(iv)(A& B) <br />As discussed in Section 2.05.6(6)(e)(i)(A), Brief Description of Mining Method, the longwall <br />mining method is planned for Apache Rocks and Box Canyon mining areas. An east-west panel <br />layout, is planned except for the two northeast panels (LONE and 11NE) which are orientated in a <br />north-south direction. Longwall mining of the E Seam (in Sections 32, 33 and 34 of T13S and in <br />Section 3, 4, 9 and 10 of T14S) is planned in the South of Divide mining area. Although longwall <br />mining may initially induce more caving and fracturing of the roof rocks as compared to the room- <br />?OS-195 Revised Novembes 10P4 PRIG <br />