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z r <br /> 0 <br /> EXHIBIT U <br /> GEOTECHNICAL STABILITY EXHIBIT <br /> U-1 SURFACE STABILITY AND POTENTIAL GEOLOGIC HAZARDS <br /> The Uinta Formation is the dominant surface geological unit cropping out within, and in proximity of <br /> the Lease. In the vicinity of the Lease, four tongues of the Uinta Formation and four interstratified <br /> tongues of the Green River Formation have been mapped along with the surface alluvium (Duncan, <br /> 1976a and b). Duncan's Tu5 unit underlays the majority of the Lease. The unit is dominated by <br /> buff-weathering silty marlstone and brown-weathering, ledgeforming sandstone. Small outcrops of <br /> channel-form, cross-stratified, medium to fine grained sandstone can be found in some of the <br /> shallow valleys on the Lease. Silts, sands, and gravels comprise the alluvium in the valleys. Flood- <br /> plain alluvium is primarily silts, sands, and clays. Along the flanks of Yellow Creek, Corral Gulch, <br /> and Stake Springs Draw, small alluvial fans are present consisting of angular lithic casts (boulders <br /> to pebbles) of sandstone and marlstone mixed with silt and sand. Some valley-bottom alluvium <br /> may reach a thickness of 100 feet. <br /> Structural disturbance of outcrops on the Lease is minimal and often difficult to detect. The primary <br /> structural feature near the Lease is the South Rangely Syncline. Rock units to the south and <br /> southwest of the synclinal axis generally strike north 50 degrees west and dip to the northeast at <br /> about 2 degrees. Rock units to the north and northeast of the axis have similar strikes, and dip to <br /> the southwest at about 2 degrees. No major faults are known to be present on the Lease. The <br /> Dudley Bluffs Graben is east-southeast of the Lease and according to Duncan (1976a and b), the <br /> fault system dies out approximately four to five miles east of the Rock School Lease. Smith and <br /> Whitney (1979) have extended the lineament to include joint sets that extend to within three to four <br /> miles east of the Rock School Lease. Thus, there are no known major fault hazards in the <br /> immediate area of the Lease. <br /> According to Simon (1972), the Lease area is in a region of low seismicity. Seismic frequency is <br /> less than one event per decade per square degree of latitude and longitude. Thus, seismic activity <br /> will not constitute a geologic hazard to nahcolite resource development on the Rock School Lease. <br /> Surface hazards, such as landslides, rock-fall areas, slumps, soil creep, and mudflows are not <br /> known to be active on the Lease area. Also, the majority of topography of the Lease area is not <br /> conducive to mass wasting or slope failure hazards except during unusually intense periods of <br /> precipitation. <br /> G:\LMM78545.002\Reclamation\ReGamexh.DOC U-1 <br />