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Map Unit 6 - Topsoiled Regraded Spoil , 2 to 15 Percent Slopes <br /> This neap unit is associated with the gently to moderately sloping upland <br /> benches, ridgetops, and sideslopes. Vegetation consists primarily of <br /> cheatgrass , crested wheatgrass, and Indian ricegrass. This map unit <br /> occurs in areas which were previously mined. Following mining , spoil <br /> piles were graded to approximate original contour, and suitable topsoil <br /> was replaced. This map unit occurs on 10. 1 percent of the study area <br /> (Table 9-4-3) . <br /> The replaced topsoil and regraded spoil have suitable physical and <br /> chemical properties (Tables 9-4-2 and 9-4-5) . Typically, the regraded <br /> spoil is slightly more acidic, has a higher sulfate content and has a <br /> higher salinity than the replaced topsoil . Based upon six sampled <br /> profiles, (Table 9-4-4) about six inches of suitable topsoil is <br /> available for salvage within Map Unit 6. <br /> Map Unit 7 - Topsoiled Disturbed Land, Shallow, 2 to 15 Percent Slopes <br /> This map unit is associated with the gently to moderately sloping upland <br /> benches. Vegetation consists primarily of crested wheatgrass, <br /> cheatgrass, smooth brome, intermediate wheatgrass, Indian ricegrass, <br /> sagebrush, and rabbitbrush. The upper horizons (A, B, C 1) of this soil <br /> unit were disturbed or salvaged during previous mining activity (i .e. , <br /> topsoil stockpiles , roads, and ahead-of-mining topsoil salvage) . <br /> Subsequently, five to eight inches of topsoil was replaced over light <br /> yellowish-brown sandstone. This soil occupies 6.8 percent of the study <br /> area (Table 9-4-3) . <br /> Chemical and physical properties for the replaced topsoil are suitable <br /> (Tables 9-4-2 and 9-4-5) . Coarse fragment contents typically range from <br /> 10 to 40 percent. Occasionally, the C1 horizon contains up to 65 <br /> percent sandstone. Based upon ten profiles (Table 9-4-4) , about seven <br /> inches of suitable topsoil is available for salvage within Map Unit 7. <br /> Map Unit 8 - Subsoiled Regraded Spoil , 2 to 15 Percent Slopes <br /> This map unit is associated with the gently to moderately sloping upland <br /> benches, ridgetops, and sideslopes. Vegetation consists primarily of <br /> 9-4-24 Pevised 11/01/86 <br />