2019-04-13_REVISION - M1984168 (9)

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WILLIAMS FORK MINING COMPANY SAND AND GRAVEL SITE Exhibit I............ Site Assessment for Soils 1.0 Legal Description W-1/2 of the SW-1/4, Section 16, Ta6N, R91W (Figure 1). Permit area-83.3 acres(Exhibit C map). Actual proposed mined area-65.3 acres (Exhibit C map) 2.0 Soils (Figure 2) The proposed permit area is mapped by the Natural Resources Conservation Service as AW-Cumulic Haploquolls, occasionally flooded (SW-1/4, SW-1/4, Section 16)and Absher very fine, sandy loam (SW-1/4, SW-1/4, Section 16). (See SCS soil descriptions.) AW soils are deep, poorly drained, and are formed in alluvium on flood plains and stream terraces at elevations of 6,000 to 7,000 feet. Included in this mapping unit are small areas of Homelake soils. Generally, the A horizon is a dark gray loam about twenty inches thick. The subsoil material is stratified loam, clay loam or clay. In some areas, sand and gravel is at a depth of thirty to sixty inches. Surface runoff is slow and erosion hazard from wind and water is slight. Absher soils are deep, well-drained, and are formed in mixed alluvium on flood plains and terraces at elevations of 6,000 to 7,000 feet. Included in this unit are small areas of Tisworth, Battlement and Glendive soils. Typically, the surface layer is light brownish gray, very fine, sandy loam two inches thick. The subsoil is very strongly alkaline, dark grayish brown and brown silty clay loam 23 inches thick. The substratum to a depth of sixty inches or more is a very strongly alkaline, pale brown loam. Permeability and runoff of Absher soil is slow and the hazard of water erosion is low, although hazard of soil blowing is high. The suitability of this soil type as source material for topsoil or roadfill is poor. Absher soils will not be salvaged due to the poor suitability for reclamation purposes. A complete description of these soils is provided in Attachment 1-1. Strippable topsoil (i.e., topsoil that can be salvaged by scrapers and is composed of all A horizons and those B horizons that do not have a high clay or sand content)will be salvaged prior to distur- bance. The topsoil depths (on AW soils) range from 10 inches to 28 inches with a mean (x)of 19.0 inches. (Depths of the associated A horizon ranged from zero inches to twelve inches with a mean (x)of 4.0 inches.) (See Exhibit C map for locations As of September 2020, the total life-of-mine disturbance is projected to be approximately 65.3 acres. The three reclaimed ponds, excluding islands, are expected to encompass approximately 36.3 acres. The amount of replacement topsoil for the remaining 17.5 acres, including islands, will be between 16 and 19 inches. Therefore, approximately 39,900 bank cubic yards of topsoil will be needed for replacement. Presently, 25,370 cubic yards are in stockpile; therefore, 14,530 yards remain to be salvaged for future replacement. FVUsh 4/19 [sgpermit] Revision- -T CI-0 Approved