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coal. The coal to be mined lies within a 392foot interval in the Fairfield Member of the Williams <br /> Fork Formation. The quality of the coal seams is midway between bituminous and <br /> subbituminous. Underlying these coal beds are 9,000 feet of Mesozoic and 4,500 feet of <br /> Paleozoic sediments. The Williams Fork Formation is estimated to be 1,600 feet thick in the <br /> permit area and is underlain by the ridgeforming Trout Creek Sandstone member of the Iles <br /> Formation. <br /> Overburden material consists of a sequence of sedimentary claystones, siltstones, shales and <br /> carbonaceous silty shales. These sediments are typical of the cyclothems deposited along the <br /> western interior of North America during the Late Cretaceous time. The sitespecific stratigraphy <br /> is described in Exhibit 6 and on Map 8 of the PAP. There are four coal seams below the "F" <br /> seam which cannot be economically mined by surface mining methods. <br /> Results of test borings are included in Section 2.04.6 of Volume 1 (East and West Pit), Volume <br /> 12 (South Taylor Pit and Lower Wilson Area), and Volumel5 (Collom Pit) of the PAP. Test <br /> borings resulted in information on the presence of subsurface water, characterization of the <br /> physical properties of the overburden, and testing and evaluation of the geochemical properties <br /> of the overburden. Additional discussion of the results of this testing can be found in Section III <br /> E of the Findings section of this document. <br /> 4.6 Climate <br /> Climatic information is found in Section 2.04.8 of Volume 1 of the PAP. The region is <br /> characterized by a semiarid steppe climate regime. Precipitation averages 18 inches per year <br /> with a significant portion of this yearly precipitation occurring as snowfall. Prevailing winds <br /> over the permit area are from the southwest and average eight to nine miles per hour. High <br /> winds are not common due to the protection afforded by local terrain. <br /> 4.7 Soils <br /> Soils information is found in Section B, Item IV of this document, as well as in Section 2.04.9 of <br /> Volume 1, Volume 12 and Volume 15 as well as Exhibit 9 of the PAP. The most prevalent soils, <br /> including Burnette, Work, Lamphier, Rhone, and Northwater Loams, are mollisols of the <br /> suborder boroll, which developed from residuum or colluvium on gently sloping to rolling <br /> ridgetops, moderately steep sideslopes, and in gently sloping, concave narrow stream valleys. <br /> Shallow, rocky soils of the order entisol occur to a limited extent within the area to be disturbed <br /> on steep, southfacing slopes. The very thick Silas loam soil, developed from alluvium, is found <br /> within narrow bands along the larger ephemeral drainages. <br /> The predominant hill-slope soils have relatively thick, loamy textured mollic epipedons, well <br /> suited for reclamation use. Salvageable thickness of these soils average from 12 inches to 30 <br /> inches. Subsoils in these units are somewhat marginal due to heavier texture or excessive <br /> cobbles. The Silas loam soil along the drainage valley bottoms is generally suitable for salvage <br /> to depths of five feet or more. <br /> Proposed Decision and Findings of Compliance January 5,2023 <br /> Permit Renewal No. 8 Page 118 <br />