2022-04-08_PERMIT FILE - C1981044 (4)

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• Possible development of surface cracking where the overburden is less than 500 feet thick and the soil cover is thin. The predicted maximum possible worst-case subsidence for the various structures and renewable resource lands is summarized on Table 79,Maximum Predicted Worst Case Subsidence on Structures and Renewable Resource Lands. A summary of the anticipated degree of subsidence impacts on structures and renewable resource lands is presented on Table 80, Anticipated Degree of Subsidence Impact on Structures and Renewable Resource Lands Based on Maximum Predicted Worst Case Subsidence. The following is a description of the worst possible consequences of subsidence on the structures and renewable resource lands identified on Table 78, Inventory of Structures and Renewable Resource Lands, which may occur as a result of mining in the Permit Area. Structures Mine Facilities(Not Undermined). The mine facilities located at or adjacent to the portal areas for the No. 5,No. 5A, and No. 9 Mines will not be undermined. Since these structures will not be undermined and are outside the area of influence of surface subsidence resulting from the planned underground mining, they will not be impacted by subsidence. Mine Facilities (Presently Undermined). The mine facilities within the Permit Area that are presently undermined are located over development entries (mains and sub-mains) which are designed to remain stable for the life of the mine. These areas have been protected against subsidence damage by assuring that sufficient coal has been left in-place as pillars to prevent or minimize subsidence in these areas. In addition, areas of Trapper Mining, Inc.'s surface mining operation which have been previously mined and reclaimed have been partially undermined. The Trapper Mining reclaimed areas that have been undermined, were undermined without any material damage. Given these considerations,no subsidence impacts have occurred or are anticipated for these structures and areas. Mine Facilities (Previously Planned To Be Undermined). The mine facilities under which proposed mining would have been conducted include MCM's underground F-Seam and P-Seam workings. Mining undermined underground mine workings in the No. 5 Mine, however, none of the No. 9 Mine workings have been undermined to date, and no future mining is planned, so potential impacts will be limited to those that have already occurred. The MCM surface facilities that would have been undermined include Sedimentation Ponds SH-P1, SH-P2 and the associated Old Shop and storage area and the Storage and Wood Shop (both reclaimed in 2008), a rock dust tank(removed), the contractor staging area,and the Okie Plaza Well. The MCM surface facilities that would have been undermined by potential future operations in the E-Seam include: 1) Old Shop and storage area; 2) Ponds SH-P1 and SH-P2 and associated ditches SH-D2 and SH-D3; 3)Rock-dust tank; 4) contractor staging area; 5) Storage and Wood Shop; and 6) Okie Plaza Well. The Old Shop and storage area, rock dust tank, and Storage and Wood Shop,and associated disturbance areas have been reclaimed. Since no future mining is planned, Ponds SH-P1 and SH-P2 and ditches SH-D2 and SH-D3 will not be impacted. No facilities except an empty water tank are located at the contractor staging area, so no effects are anticipated. The Okie Plaza Well will not be undermined. The only underground workings that have been undermined are limited areas of underground development entries. Portions of the No. 5 Mine mains and sub-mains are located over development entries (mains and sub-mains) of the No. 6 Mine. The No. 6 Mine development entries are designed to remain stable for the life of the mine. These areas are protected against subsidence damage by assuring that sufficient coal has been left in-place as pillars to prevent subsidence in these areas. Therefore,there will be no subsidence impact on the existing workings. RN18-07 2.05-51 Revised 10/19/18