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crosses the northern portion of the Lease area. The two synclinal axes produce a <br />small basin which underlies the entire property. Structural relief for the Lease is <br />. <br />about 730 feet; dips range from 1.00 to 2.50 <br />A fault or fracture system crosses the southwestern corner of the Lease. This <br />feature represents an extension of the Dudley Bluffs Graben, a major fault system <br />which originates at the Piceance Creek Dome about 10 miles to the southeast. As <br />the Dudley Bluffs Graben approaches the Lease it loses definition and intensity. The <br />significance of the Dudley Bluffs system in the Lease area is not known at the <br />present time. It probably will not adversely affect exploitation of saline minerals in <br />the Saline Zone; however, it could influence groundwater storage and movement in <br />units above the Saline Zone, whereby substantial leakage would occur from the R-8 <br />zone and above units through the Mahogany Zone. <br />Rocks above the Saline Zone (1,700 to 1,900 feet thick) contain numerous fractures. <br />Most are associated with the Leached Zone and lower Mahogany Zone, and were <br />probably produced by dissolution of saline minerals (i.e., subsidence). Other <br />fractures were produced tectonically during development of the South Rangely <br />Syncline or Dudley Bluffs Graben. Rocks in the Saline Zone have much fewer <br />fractures relative to the rest of the Parachute Creek Member and Uinta Formation. <br />Most open fractures in the Saline Zone have been healed by secondary precipitation <br />of calcite or saline minerals, mainly white crystalline nahcolite. Some fractures in the <br />L-3 and L-2 zones have infillings of organic matter. <br />In summary, the Federal Sodium Leases have the following geological <br />characteristics: <br />1. A uniform and predictable stratigraphic framework within the Uinta Formation and <br />Parachute Creek Member of the Green River Formation. <br />2. Abundant resources of oil shale, nahcolite, dawsonite and halite. Numerous <br />mappable nahcolite and halite beds exist in the Saline Zone. <br />Daub $ Associates, Inc. Page 4-6 NSI Mine Plan 2010 Rev. <br />Printed: 7/5/2010 Section 4 Geology