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D-3 MINING TECHNOLOGY AND PROCESS <br /> D-3.1 INTRODUCTION <br /> The bedded and disseminated nahcolite deposit to be mined is at an average depth below <br /> ground surface of from approximately 2,000 to 2,600 feet. Included in this interval are three <br /> bedded nahcolite horizons: the Love Bed, the Greeno Bed and the T1 Bed. A stratigraphic <br /> section which includes the nahcolite deposit is shown in Figure D-3.1. Across the mining <br /> interval the deposit consists of approximately 24 to 32 weight percent nahcolite. The <br /> remaining matrix consists primarily of oil shale and marlstones. <br /> In the area of the Rock School Lease the Uinta Formation is approximately 800 to 950 feet <br /> thick. It is comprised of four units or tongues of the Uinta, interstratified with three tongues <br /> of the Green River Formation. The tongues of the two formations are the TU5, TU4, TU3, <br /> "Transition Zone", and the Thirteenmile, Dry Fork, and Yellow Creek, respectively. The <br /> tongues of the Green River Formation are primarily composed of marlstone, lean oil shale, <br /> and some silty marlstone. The tongues of the Uinta are primarily sandstone, siltstone, silty <br /> marlstone and marly siltstone. As a group, the rocks of the Uinta Formation (including <br /> Green River Formation tongues) become finer grained, thinner bedded, more pyritic, more <br /> organic rich and more calcareous with depth. The three nahcolite resource intervals to be <br /> mined will primarily involve only the upper part of the Green River Formation, specifically the <br /> Parachute Creek member below the Dissolution Surface (Saline Zone) where ground water <br /> has not dissolved recoverable saline minerals. Drilling will also intersect the overlying Uinta <br /> Formation. This interval (surface to objective) is in excess of 2000 feet in thickness beneath <br /> the Rock School Lease area. <br /> Based on available core-hole information, the stratigraphic section between the Love bed <br /> and the Dissolution surface ranges from about 300 feet to more than 600 feet. This interval <br /> of rock is composed of oil shale and saline-mineral beds that are competent and essentially <br /> free of fractures. The thickness and competency of this rock interval will serve as an <br /> excellent barrier between ground water and the mining cavities during the solution mining <br /> operations. This competent interval will also offer excellent roof support stability for the <br /> solution mining intervals. <br /> G:\LMVN78545.002\Reclamation%Reciamexh.DOC D-14 <br />