2013-04-10_PERMIT FILE - C1981019A (13)

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RULE 2 PERMITS material suitable for salvage (generally the entire thickness of the solum or to a depth of high coarse fragment content or lithic contact). Present and potential productivity of the soil units are provided in Table 2.04.9 -15. The disturbance area is comprised primarily of the sagebrush plant community over approximately 1,000 acres and mountain shrub over approximately 830 acres. Herbaceous production on these vegetative communities averages near 774 and 927 pounds per acre, respectively. The most prominent soil type within the disturbance area is the Duffymont - Nortez soil complex. The primary plant community on this soil is sagebrush. The Duffeymont soil is limited by the presence of bedrock at depths ranging from six to 20 inches and the Nortez soil has bedrock occurring from 20 to 40 inches. The Duffymont soil is formed in slope alluvium and colluvium over sandstone bedrock while the Nortez soil formed from loess deposited over alluvial and residual sedimentary materials. The Duffymont soil available for salvage is loamy and has high nutrient levels. The Nortez series is comprised primarily of clay loams over clay subsoil. The primary limiting characteristics of the Nortez soil are the shallow depth to bedrock and high coarse fragment content (usually over 35 percent) found in the subsoil. These soils should be capable of producing similar revegetation production should appropriate best management practices be conducted for reclamation. The primary soil hosting the mountain shrub community is the Thornburgh - Lithic Haplocryolls soil complex. The Thornburgh series consists of moderately deep, well- drained soils that formed in colluvium and alluvium derived from sedimentary rocks. The weakly developed Thornburgh soils are found on steep side slopes and toe slopes. The primary limiting characteristics of this series are low nutrient content, weak soil development and high coarse fragment content in the subsoil. This soil is lower in nutrient content than most of the other nearby Cryolls. This is likely due to the coarser texture and attendant low moisture holding capacity, which allows for leaching of nutrients through the profile. The Lithic Haplocryolls are very similar to the Duffymont series discussed above but have been determined to be a Cryic temperature regime. The mountain shrub community is the dominant plant community on these soils likely due to additional precipitation and lower evapotranspiration. Due to the poor soil development of the Thornburgh soil series, additional care in stripping and handling are needed for acceptable post - reclamation production. However, stripping and stockpiling of the A horizon (usually 12 inches or less) should produce successful revegetation results. Detailed Soils Resource Information — The site - specific soils resource information described below pertains to the proposed disturbed area associated with the Collom mining area shown on Map 5D (Sheet 1) and included in detail in the Baseline Soil Survey (Exhibit 9, Item 8). Detailed soils information was collected to determine the spatial distribution, suitability, salvage depths and volume of soils available within the disturbed area associated with the Collom permit expansion area. In addition, the mass balance in salvageable soil materials were calculated to assure an adequate supply of suitable soil would be available for reclamation of the surface disturbance associated with the Collom permit expansion area. The results of the mass balance analysis are presented in Table 2.04.9 -16 Topsoil Mass Balance — Collom Mine Area. Soil series were described and sampled in locations that were typical of the series. Samples were collected from 95 pedons determined in the field to be representative of soils in the area. These samples were collected entirely from within the Order II Survey Area. Selected soil samples were generally collected from pedons where the soil series or family was a dominant component of the map unit. Soil samples were collected from horizons greater than three inches thick. Horizons less than three inches thick were occasionally sampled along with the most similar adjacent horizon, unless the horizon was anomalous in nature. Horizons greeter than 18 inches thick were collected from the lower portion of the soil horizon. One to eight samples were collected from each sampled pedon, with more than four samples Collom — Rule 2, Page 50 Revision Date: 9/28/11 Revision No.: PR -03