2016-01-14_REVISION - M1983194 (2)

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Daub & Associates, Inc. Page 3-22 2015 NS Mine Plan Modification 1/5/2016 Section 3 General Site Conditions The Project Area is within a small topographic basin located about 40 miles northwest of Rifle, Colorado. This small basin is part of the larger northwest trending Piceance Creek Basin. Landscape of this area is characterized by relatively flat hills, ridges, and shallow gulches or canyons. Drainages have a trellis-like pattern with parallel ridges and gulches that drain in a north and northwestern direction toward Yellow Creek. Elevations range from 6,200 feet at Yellow Creek to 5,700 feet at the southern edge of the Project Area. The canyon walls along Yellow Creek can be up to 160 feet high, while the ridge tops are only 60 to 80 feet above the surrounding terrain in the upper drainages. 3.8.2. Soil Survey Procedures The Rio Blanco County Soil Surveys (SCS, 1982) were used for the Order 3 survey on the sodium lease area and was the primary source of soil information for the Project Area. In addition, an intensive Order 2 soil survey (SCS, National Soils Handbook (NSH)-undated) was conducted on the Project Area according to SCS guidelines. These data were supplemented by photo interpretation and laboratory analyses. The soil survey and sampling were completed during August of 1984. The soils distribution on approximately 1,620 acres was mapped on aerial photographs at a scale of approximately 1:6,000 (Plate 3-1, see map pocket at end of section). A detailed soil map around the NS plant is illustrated in Figure 3-2. Soil patterns were studied in different landscapes, and the soil boundaries were predicted according to features such as physiographic position, vegetation, parent material, and soil morphology. Soil patterns described in the Rio Blanco Soil Survey and landscape features were used to establish the soils mapping unit boundaries. A number of soil profiles were evaluated to determine the nature and extent of soils in a mapping unit. Soil characteristics were examined in road cuts, gullies and hand-dug sample holes. The hand-dug holes were excavated to a depth of 32 inches. The lower substrata were examined by means of a 3-inch diameter hand auger to a minimum depth of 60 inches or to indurated bedrock, whichever occurred first. General soil descriptions were taken and compared to the established SCS soil series description.