2022-09-29_PERMIT FILE - C1980007 (5)

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Subsidence Evaluation for the Exhibit 60E Southern Panels, Apache Rocks West, & Sunset Trail Mining Areas Page 38 831-032.923 Wright Water Engineers, Inc. December 2021 11.5 Roads As was observed in the Apache Rocks and Box Canyon mining areas, effects from mine subsidence are typically limited to cracks that do not prevent passage on most of the access roads and drill roads in the Southern Panels mining area. Also, as expected, no effects from landslide movements or rockfalls have occurred, because the mining rockfall potential is mapped in the moderate-high category or lower, and rockfalls were observed to occur only in the high to very high rockfall category areas in the Box Canyon mining area. No cracks have been observed in the soft, pliable alluvium, but a few cracks have occurred on the harder and more highly compacted Dry Fork access road, particularly in the area near the confluence of Deer Creek and Dry Fork, although all have been of a small extent. Observations along these roads are documented in the semi-annual Subsidence and Geologic Field Observations reports. 11.6 Buildings Baseline information on buildings, such as foundations, walls, chimneys, and roofs, has already been obtained on the Dry Fork Cow Camp in July 2004 (Dunrud 2004b) prior to any mining. A pre-mining survey of the Cow Camp structures was performed by West Elk Land Surveying in February 2006 and is included as Exhibit 73. The Minnesota Creek ditch rider's cabin is located near the headwaters of Dry Fork in the Dry Fork mining area. An exterior inspection of the cabin was performed in 2004 by the U.S. Forest Service and Agapito Associates, Inc. (Agapito, 2005). The structure was reported to be in average structural condition. 11.6.1 Lower Dry Fork Cow Camp The cabin exterior is approximately 13 feet wide, 20 feet long, and 8.5 feet high (the wall height). A lean-to 7 feet long and a porch 5.5 feet wide are located on the north and south ends of the cabin (see Figures 7 and 8, of Exhibit 60D for details). The outside walls are of a wood, board-and-bat construction. The foundation, which is of rock and mortar construction (and an estimated 1½ feet thick), ranges from about 1 foot high in the back to 20 inches high in the front. The roof is covered with tin. The side windows, which measure 2 by 3 feet in outside dimension, are located in the approximate center of either wall. Post-mining observations and measurements of the cabin following mining have been documented in the Subsidence and Geologic Field Observations Reports. 11.6.2 Minnesota Creek Ditch Rider’s Cabin This cabin was built in the 1950's and is 24 feet 4 inches by 16 feet 4 inches single-story wood framed building. The cabin is located over the projected potential extended eastern end of E-seam longwall panel E6.