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West Elk Mine <br />of subsidence and subsequent healing. The discussion of the field observations will in <br />particular address the development and healing of the subsidence features, utilizing the <br />. photographic documentation. In addition, MCC will discuss baseline conditions observed in <br />azeas prior to undermining. The report will document how the inspection was conducted, and <br />include such 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 training, and after mining when subsidence is <br />complete to document landslides, rockfalls, vegetation, etc. over the azeas being trained. 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 monumem grid, as shown on Map 29. The <br />surveys were designed to achieve horizontal accuracies complying with the U.S. Department of <br />Commerce's "Second order, Class II" surveying standazds, and vertical accuracies no less than <br />0.2 feet. Grids were surveyed twice prior to the initiation of subsidence. A minimum of six <br />triangulation bench tnark monuments outside the area of anticipated subsidence effects were <br />selected and established. Monitoring of the grid was discontimted in 1999. Subsidence <br />monitoring reports are submitted on an annual basis, due by September 30 of each year. Aerial <br />photos taken will be maintained at the West Elk Mine. <br />Monitoring Freauencv - 2.05.6 (6)(b)(DtD,E&F> <br />~• The photogrammetric subsidence monitoring program will contimte to be performed semi- <br />annually and reported (as approved per MR96) to the CDMG semi-annually, as well. <br />Subsidence Control Plan - 2.05.6 (6)(b)(iii)(S), (6)(d)(i&ii), (6)(e)(iv} & (6){f)(i-vii) <br />Description of MininP Methods - 2.05.6 (6)(fl(ii)(ABeB) <br />As discussed in the grevious section (2.05.6(6)(e)(i)(A), Br(ef Description of Mining Method, the <br />longwall mining method is planned for the Apache Rocks and Box Canyon training areas. An <br />east-west panel layout, is planned except for the two northeast panels (LONE and 11NE) which are <br />orientated in a north-south direction. Development mining will employ room-and-pillar metltods. <br />Specific panel geometry and pillar design are discussed in the above referenced section. <br />Longwal] mining is currently planned for extraction of the B-Seam and E-Seam (in Sections 29 <br />and 30) in the Apache Rocks and the Box Canyon mining azeas. Although longwall training may <br />initially induce more caving and fracturing of the roof rocks as compared to the room-and-pillar <br />method due to the complete removal of coal in the panel, it offers the advantages of max;m; ;.+g <br />resource recovery. The longwall method also causes more complete subsidence (full extraction of <br />panel) and causes equilibrium conditions to be reached in a shorter period of time (i.e., there is no <br />additional, lingering pillar crushing in panels). As such, to the extent possible, the longwall <br />panels should be located so that barriers or boundaries, particularly in low cover areas, are not <br />2.05-135 RevisedJ'm 1995 PR06; 1/96 RN03; RevisedMay 1999 TR89; RevisedJmi. 1000 PR08 <br />