1999-04-26_PERMIT FILE - M1999051

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The nahcolite that will be solution mined is located in the lower part of the Saline zone. This zone contains disseminated nahcolite nodules, aggregate, crystals and beds of nahcolite that vary from a few percent to as much as 70 weight percent nahcolite. There are three resource intervals of particular mining interest as indicated above. From the upper to the lowest interval, these are the: Love Resource Interval, Greeno Resource Interval and TI Resource Interval. Each of these stratigraphic intervals could be solution mined using the same vertical well. The TI interval can be mined first and the Greeno and Love intervals would be mined in consecutive order or mined as a single unit. A cavity with a height of the entire resource interval (up to 600 feet) and a diameter of from 75 feet to 225 feet could be formed. The solution cavern will be supported by undissolved residual oil shale which constitutes approximately 80% of the original volume of the cavern material. The undissolved residual material will essentially fill the cavern resisting both wall and roof collapse. The cavity is expected to be structurally sound because only the sodium minerals are removed; the organic oil shale matrix remains nearly intact and is capable of supporting the overburden. Intervening pillars would separate the cylindrical cavities for mechanical support. Figure D-3.2 shows the general solution mining scheme and cavity arrangement for the 50,000 tpy pilot plant. The AmerAlia pilot process is designed to produce animal feed and industrial grade sodium bicarbonate. Uses include: fire extinguisher manufacturing; production of chemicals, textiles, plastics, detergents, rubber and numerous household products. It could also be a major alkali for the reduction of S02 and NOx from coal-fired boilers. The 50,000 tpy pilot plant will initially produce animal feed grade sodium bicarbonate. Favorable experimental pilot results would allow modifications to achieve commercial operations including food grade sodium bicarbonate. These modifications and plant expansions may increase the production capacity to 150,000 tpy. D-3.3 DRILLING, COMPLETION AND ABANDONMENT OF PRODUCTION WELLS The following is a description of the anticipated drilling and completion techniques for the production wells. The pilot phase of the project will have up to six production wells as shown in Figure D-3.2. Flexible drilling and completion techniques are needed to achieve the goals of the experimental pilot project. As an example, the drilling will begin with an auger or bucket type drill rig which will drill a 17'h inch diameter hole into bedrock to secure the G:\LM=78545.002\Reclamation\Reciamexh.DOC D-18