2012-06-20_PERMIT FILE - C2010089 (88)

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6 Mine Number Mine Name 75. WY -14 FMC 76. WY -15 Jacobs Ranch 77. WY -16 Grass Creek 78. WY -17 Jim Bridger 80. WY -18 Lake De Smet 81. WY -19 Medicine Bow 82. WY -20 Muddy Creek 83. WY -21 North Rawhide 84. WY -22 P.S.0.#1 85. WY -23 Rimrock 86. WY -24 Rochelle 87. WY -25 Rosebud 88. WY -26 Seminoe #1 89, WY -27 Seminoe #2 90. WY -28 Sorenson & Elkol 93. WY -29 Twin Creek 94. WY -30 Welch 95. WY -31 Whitney 96. WY -32 Wyodak 76. TABLE 3 (Cont'd) Total Area... "AVF" Area... (mi (hectares) (mi (hectares) 17.79 4,608 - -- - -- 10.21 2,644 0.28 72 1.15 298 - -- - -- 41.28 10,692 0.05 13 37.63 9,746 0.58 150 27.74 7,185 0.22 57 1.98 513 0.10 26 22.95 5,944 2.49 645 1.01 262 0.06 16 21.36 5,532 0.34 88 14.89 3,856 0.11 28 17.95 4,649 0.11 28 19.37 5,017 0.12 31 24.60 6,371 - -- - -- 38.53 9,979 - -- - -- 8.78 2,274 0.89 230 3.05 790 0.89 230 3.29 852 1.22 316 8.04 2,082 '0.83 215 1427.94 30783b' 42.48 11,002 77. is likewise located north of the coal presently surface mineable and within a drainage channel not likely to be mined. The Welch Mine (Mine Number 94 or WY -30) is not located in the Tongue River alluvial valley floor, but the description of the lease area includes 8.89 hectares of alluvial valley floor. On the other hand, the Wyodak Tine Olin Number 96 or WY -32) is currently lo- cated entirely within the alluvial valley floor of Donkey Creek. The Whitney Mine (Mine Number 95 or WY -31) is proposed to be located partially within an alluvial val- ley floor (37% of lease tract is an alluvial valley floor). The Belle Ayr Mine (Mine Number 63 or WY -2) is operating in an alluvial valley floor. The Big Horn Mine (Mine Number 64 or WY -3) has involved the alluvial valley floor of a stream tributary to the Tongue River and lies adjacent to the alluvial valley floor of the Tongue River. As we shall explain in the next section, more area than that sug- gested by Table 3 may be affected by avoidance of alluvial valley floors during min- ing in cases where the mines are adjacent to an otherwise impact the hydrology of subirrigated alluvial valley floors. Since valley areas examined at vine sites located in more arid climates did not show equal evidence of year - around subirrigation (equal to that shown in the semi- arid areas of the Northern Great Plains), only a few alluvial valley floors were identified for New Mexico, Arizona, Utah, and southwestern Wyoming. This reconnais- sance investigation did not find the vegetation of most drainages in New Mexico, Arizona, Utah, or southwestern Wyoming to show vigorous growth during the dry months. However, it may be that the spring and winter precipitation in these lowlands is sufficient for enough forage to be produced at those times to make a significant positive impact on grazing. The lowland areas in the arid climates may be important by virtue of their providing some degree of protection from wind. These attributes of alluvial valley floors do not appear to be addressed in the legislative proposals and were not measured during the assessment described herein. A detailed field study of the role of lowland drainage areas in agriculture and of the critical geo- hydrologic factors supporting that role is especially needed in the New Mexico, Ari- zona, and southwestern Wyoming coal regions. it is noted again that the percent "imposition ", or surface conflict between alluvial valley floors and the surface of coal mine tracts cannot be translated directly to coal production "losses ", since loss is determined by the technology available to mine the particular coal under site- specific geologic and hydrologic circumstances. The data in Table 3 could be directly translated into an effect on shallow coal only if, for simplicity, it were assumed that (1) all alluvial valley floors on mine leaseholds overlie shallow coal; (2) no coal underlying an alluvial valley floor can be mined; (3) the coal were evenly distributed over the tract such that the percentage of coal affected was the same as the percentage of land in the alluvial valley floor, and (4) mining of coal adjacent to the alluvial valley floor was compatible with protection of the valley's hydrologic system. (The second assumption would be based on a further assumption that the subirrigated alluvial valley floors could not be reclaimed.) Under these assumptions the percentage of coal removed from near- future production on the leasehold would be 2.97 percent. However, that translation may be misleading because additional coal might be affected because of its relationship with the subirrigated alluvial valley floor; or less coal might be affected if the valley floor could be reclaimed. The following section attempts to project impacts of a ban on the mining of alluvial valley floors on the shallow coal resource. This will be done by analyses of a few hypothetical, yet reasonable, geologic - hydrologic situations. A more comprehensive analysis would re- quire the evaluation of site - specific circumstances and field measurements to deter- mine what mining technologies might be utilized and how the mining operation might be developed to protect the integrity of the alluvial valley floor. The point remains though, that the percentages that may be calculated to show areas of land overlying surface mineable coal based on the data in Table 3 do not represent the amount of coal that will be affected if reclamation after mining these and adjacent lands cannot reestablish the critical hydrologic balance that supports the alluvial valley floor.