2015-02-26_REPORT - C1982056 (3)

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SubTerra, Inc. Peabody Twentymile Coal LLC 09/27/2014 Foidel Creek Mine Permit Revision for Longwall Mining in the Wolf Creek Seam - Subsidence Evaluation (c) Subsidence Monitoring Program. (i) The monitoring program shall be designed to determine the commencement and magnitude of subsidence movements which occur and shall include the following monitoring techniques: (A) Monuments shall be installed and surveyed prior to the commencement of mining. (B) Monuments shall be situated to appropriately monitor ground surface movement, vertical and horizontal, within the area proposed to be undermined, including an area to accommodate the predicted angle -of -draw. (C) The orientation, location and elevation of each structure within the permit and adjacent area shall be monitored. (D) Monitoring of established monuments and structures shall be performed at least quarterly, commencing one month prior to the initiation of mining beneath any established monument or structure. (E) Results of the monitoring program shall be submitted to the Division at least semi - annually. (F) The monitoring program shall be designed to extend for a time, beyond cessation of mining in any area, consistent with the need for verification of the subsidence prediction. (ii) The application shall include an appropriate map, prepared according to the standards of Section 2.10, showing the location of monuments to be installed and structures to be monitored within the permit and adjacent area. (d) (i) If a subsidence monitoring program determines, in the opinion of the Division, that the subsidence prediction was inaccurate and that material damage or diminution of reasonably foreseeable use of structures or renewable resource lands may occur, the permittee will be required to submit a subsidence control plan, as defined in Section 2.05.6(6)(f). (ii) In order to protect structures and renewable resource lands within the permit and adjacent area, the Division, after consultation with the permittee, shall suspend underground coal mining under structures of renewable resource lands, if imminent danger of material subsidence damage or diminution of reasonably foreseeable use is determined to exist. (e) A subsidence survey, prepared by appropriately qualified professionals in accord with the current state -of -the -art of subsidence prediction technology, shall contain the following information: (i) A detailed description of subsidence predicted to occur within the permit and adjacent area, including: (A) A brief description of the planned mining methods; (B) A brief description of geologic properties which influence subsidence occurrence, such as rock mechanics character of the affected materials, geologic structure of the affected materials, faulting and fracturing of the involved geologic section, and permit and adjacent area topography; (C) A brief description of local mining experience concerning subsidence occurrence, if any; 25 PN: 2013 -26