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Longwall mining in the No. 6 Mine is planned under old room -and -pillar workings of the No. 5 Mine. The worst <br />possible consequence of longwall mining would be that the pillars in the old workings will fail and the roof caves. <br />This would effectively increase the magnitude of subsidence at the surface. Because multiple -seam mining generally <br />occurs where the surface use is limited to rangeland and wildlife habitat, worst-case subsidence impacts would have <br />no adverse effect on structures or land use. <br />Private Residences (Houses). There are three private residences located within the Permit Area, however, the <br />structures are located outside of the planned mining area. Given that the structures are located outside both the <br />planned mining area and the area of subsidence influence, the structures would not be impacted by any subsidence - <br />related surface effects. <br />Oil Pipeline. It is anticipated that subsidence effects may necessitate repairs to the oil pipeline. A general lowering of <br />the ground surface with grade changes and surface cracking may occur along the pipeline right-of-way. Plains All <br />American Pipeline, LLC, the current owner/operator of the pipeline, maintains a continuous pressure monitor on the <br />pipeline from its offices in Corpus Christi, Texas. If disruption of flow were to occur, the monitor will be triggered <br />and action will be initiated to locate and repair the leak or ruptured line. <br />MCM has maintained communications with each successive owner/operator of the pipeline to identify and coordinate <br />in assessing the most practical means to mitigate any potential adverse impacts to the pipeline, due to proposed mining <br />operations. Potential solutions include relocation of the pipeline, in-place activities necessary to protect the pipeline if <br />left in place, and modifications to mine plans. Based on plans previously developed with the pipeline owner, full <br />extraction mining operations beneath a portion of the pipeline is planned, subject to approval by the CDRMS. <br />MCM's predecessor company, RAG EC, previously coordinated with AMOCO Pipeline Company (who owned the <br />pipeline at the time) to undermine the pipeline and mitigate the associated subsidence -related impacts. In order to <br />accommodate mining of Panel 2 in the No. 6 Mine ("E" Coal), AMOCO moved the potentially affected section of the <br />pipeline beyond the angle of draw associated with Panel 2, as shown on revised Map 24. This assured a 100 -foot <br />buffer was maintained consistent with applicable permit commitments, and allowed maximum coal recovery from <br />this panel. The depth from surface to bottom of the "E" Seam at this location was 200 feet, and the angle of draw <br />distance was calculated at 19 degrees. The 100 -foot horizontal offset was a conservative to assure no subsidence <br />effects given these parameters. <br />For the pipeline segment overlying Panel 3, RAG EC, reached an agreement with AMOCO, allowing RAG EC to <br />undermine the pipeline. Under the terms of this agreement, RAG EC agreed to reimburse AMOCO for work <br />performed by AMOCO or a contractor to install a section of new pipe in the area to be undermined, and for the burial <br />of the pipeline segment upon completion of undermining. RAG EC assumed responsibility for handling of the <br />pipeline during undermining (during which time the pipeline segment in question remained uncovered, to allow <br />monitoring and temporary support adjustments as needed), and coordinated with AMOCO on periodic pipeline <br />inspections. <br />County Road 107. It is anticipated that subsidence effects may necessitate minor repairs to County Road 107. A <br />general lowering of the ground surface with slight grade changes and minor cracking may occur along the gravel road. <br />State Hi lg iway 13. State Highway 13 traverses the planned life -of -mine underground mining operations. Refer to the <br />Life -of -Mine Plan Map (Map 22). However, for any planned future mining, State Highway 13 lies outside the area of <br />Possible surface subsidence. Development mains and sub -mains were driven under State Highway 13 (see Map 24), <br />however, sufficient pillars were left in place to provide adequate long-term support and prevent or minimize <br />subsidence. Standard approved methods, which stability analysis and past experience show are adequate to prevent <br />subsidence, were used. No longwall mining or pillar extraction has occurred in this area and none is planned in the <br />future. <br />TR14-36 2.05-52 Revised 03/10/14 <br />