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<br />a <br />ongoing monitoring requirements for the production fluid and tt~ <br />injection fluid by American Soda. . <br />Page 4: What verification has American Soda submitted regarding "assumed <br />production per well?" American Soda has drilled three production wells <br />under the Mine Test Plan approved by the BLM. As far as• is known, not <br />one of these wells has been mined to create a cavity with 200' diameter <br />by 600' height dimensions. I believe EPA should to review American <br />Soda's Mine Test Plan cavity mining data to determine whether the <br />applicant's assumptions should be relied upon in issuing this UIC permit. <br />Note that on page 15 of 77 in the Draft Area Permit, the inlet pressure <br />was reportedly maintained on the test production well 20-3 (a preheated, <br />developed cavity) for one week without causing fractures. These data <br />were used to justify permitting an injection pressure of up to 700 psig. <br />The reference to the test being representative of actual mined conditions <br />is somewhat misleading. Based on the production to date from 2-3 <br />cavities (7,500 tons of sodium minerals), less than 5% of the estimated <br />nahcolite has been mined. To be really representative of the suitability <br />of the proposed injection pressure, tests need to be performed on a <br />cavity with 100% of the resource mined. Thus, the inlet pressure test <br />submitted to EPA may not be applicable to mined cavities vvith substantial <br />quantities of material extracted. It is under these conditions that a <br />reasonable prediction of caving, fracturing, and subsidence could be <br />made with some level of confidence. This is not the case with the data <br />provided to EPA. Based on American Soda's commercial mine plan, the <br />Mahogany Zone (and therefore the A- and B-Groove aquifers) could be <br />in the fracture zone and the Uinta aquifer might also be in the fracture <br />zone. This is a critical issue that is indicative of the protlems of relying <br />on faulty assumptions that could lead to significant environmental <br />impacts to USDW quality aquifers overlying the project site. <br />Page 6: The Draft document states: "Data indicates there are most likely no <br />USDW's below the base of the Uinta (approximately 675 feet from the <br />r surface) at the site of this lease." I believe that inaccurate or misleading <br />information may have been provided to the EPA regarding water quality <br />in the Lower Aquifer. As I have learned over the past se~~eral months of <br />monitoring this project, water quality in the Lower Aquifer varies <br />substantially at the project location, and the Lower Aquifer should really <br />be considered as two aquifers (A-Groove and B-Groov~a), not a single <br />aquifer. <br />I am attaching several tables that are abstracted from tf ie regional data <br />base for groundwater quality and from data submitted by American Soda <br />to the Bureau of Land Management (BLM) in compliance with its Test <br />Mine Plan Water Quality Monitoring Plan. The USGS data for Well 1A and <br />2A is for Horse Draw which is about i/4 mile south of the American Soda <br />2 <br />