2024-08-29_PERMIT FILE - C1980007 (2)

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West Elk Mine 2.05-30 Rev. 06/05, 01/06, 03/06, 04&05/06- PR10; 01/09- MR350; 04/09- TR116; 05/09- MR354; 08/09- TR119; 5/20- MR443; 10/20- MR450; 10/21- MR456; 6/24-TR156 Monitoring, Sampling, Drilling and Other Temporary Facilities or Operations As needed on occasion, MCC will construct monitoring, sampling, drilling and/or other temporary facilities or operations, along with access to them, in order to supplement design or compliance data, as well as ventilation or other needs for the mine operations. As with all of MCC’s permanent facilities and operations, these facilities will be constructed, operated and reclaimed in compliance with the Regulations of the CMLRB for Coal Mining, particularly Rule 2.05. All necessary clearances, such as cultural resource reviews by the State Historic Preservation Office, will also be provided. Accesses to such facilities will typically be field-designed and constructed as described in the light-use road discussions above. No drainage alteration or relocation would typically be required for such construction. Temporary culverts would be used to provide access crossings, or low-flow fording or dry drainage crossings could be constructed in drainage areas of less than one square mile. These facilities will also be constructed more than 100’ of a public road right-of-way (except where mine roads join these rights-of way). A temporary pipe was used to reroute the flow of South Prong Creek, in accordance with methods described in section 2.05.6(6)(f), when a 0.01 acre subsidence hole developed at the confluence of the North Fork of South Prong Creek and South Prong Creek on MCC’s property. About 280’ of temporary 6” PVC pipe was laid on the ground surface and a make-shift sump was constructed out of soils and tarps. The accumulated stream flows were then routed into the temporary diversion pipe until the streambed was repaired and reclaimed. As stated in the “General Construction Procedures” discussions above, the “Hydrologic Protection During Construction” discussions below, and the “Reclamation Plan” discussions in section 2.05.4 of this permit document, the reclamation of all areas will be such that the areas will be stabilized, the hydrologic balance not impacted, topsoil salvaged, stored and replaced, and disturbed areas revegetated. The soils that are salvaged will be stockpiled in windrowed berms along the accesses and/or pads or stockpiled nearby. To reclaim these sites, the soils will be returned and compacted in most areas to the approximate original contours. Topsoil salvaged from the sites will be redistributed as evenly as possible over the recontoured areas and accesses. The soil surface will be scarified, if need be, and seeded with MCC’s approved seed mixture per Table 37. For soil and geotechnical borehole sampling, soil auger diameters are typically 10” and bedrock test holes are typically 4” in diameter. These boreholes will vary in depth, but are typically less than 50’ deep. Ventilation boreholes, gas or water monitoring wells will also vary in diameter and depth. Specific information on the configurations of these facilities will be provided in subsequent revision applications that will be included in Exhibit 80 after approved. As further described in section 2.05.4(6) of this permit document, drill holes and other borings will be sealed, backfilled and reclaimed in accordance with Rule 2.05.4(2)(g). Soil and geotechnical boreholes are backfilled by returning rock cuttings and soil materials into the boreholes. Borehole and drill hole sealing is also aided by natural healing through soil bridging. As stated in section 2.05.5 “Post Mining Land Uses”, wildlife and livestock grazing will predominately be the post- mining land-use. As also discussed in that section, should these sites later be utilized as a coal refuse pile, the reclaimed area will also serve the same post-mining land use. MCC may use prefabricated portable hinged bridges for temporary stream crossings. These bridges are fabricated from steel with a wood deck and center steel portion and are up to14’ wide and 40’ long. The bridges will typically be hauled on a tilt deck winch truck, or alternatively be skidded with an excavator or dozer. To set the bridge in place, an excavator and/or dozer will be used to position the bridge across the stream crossing. Depending on the topography of the creek crossing, road base and/or larger rock will be used on each end to build a ramp onto and off the bridge. An alternative would be to dig a notch at each end of the bridge so to place the deck level with the existing ground surface. The same equipment and processes will be used to remove the bridges and transport them to future locations. Because most of these sites and accesses are located in remote areas and/or not on previously disturbed ground, alternative sediment control measures will be utilized, including best management practices such as straw bale dikes,