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TRAPPER MINING INC. SAND AND GRAVEL SITE Exhibit I - Site Assessment for Soils 1.0 Legal Description W 1/2 of the SW 1/4, Section 16, T6N, R91W (Figure 1). Permit area - 83.3 acres (Exhibit C map). Actual mined area - 45.4 acres (Exhibit C map) 2.0 Soils (Figure 2) The proposed permit area is mapped by the Soil Conservation Service as AW-Cumulic Haploquolls, occasionally flooded (NW 1/4, SW 1/4, Sec. 16) and Absher very fine, sandy loam (SW 1/4, SW 1/4, Sec. 16). (See SCS soil descriptions.) AW soils are deep, poorly drained, and are formed in allu- vium 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 Tiaworth, 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 suita- bility 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 I-1. Strippable topsoil (i.e., topsoil that can be salvaged by scrapers and is composed of all A horizons and those B horizons Chat do not have a high clay or sand content) will be salvaged prior to disturbance. The topsoil depths Con AW soils) range from 10 inches to 28 inches with a mean (T) of 19.0 inches. (Depths of the associated A horizon ranged from zero inches to twelve inches with a mean (z) of 4.0 inches.) (See Exhibit C map for locations.) The amount of available topsoil is 112,159 cubic yards for the 45.4 acre mining area. Since the pond, after mining and reclamation, is expected to be 57 acres in size, the amount of replacement topsoil for the remaining 26.3 acres will be between 16 and 19 inches. Therefore, approximately 61,878 bank . cubic yards of topsoil shall be needed for replacemenC. Presently, 15,194 cubic yards are in stockpile; therefore, 46,684 yards remain to be sal- vaged for future replacement. JMM/jb 8/30/85