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<br />7. At a minimum, we state that the Permit should be requrred to be for a smaller area and/or <br />require a Permit for each well until there are more baseline data relating to the water issue. (This <br />issue is also addressed in the response to comment 3.) <br />8. There is concern regazding a potential impact on the solution mirilng industry if the project <br />fails. If they fail in what they are trying to do-fail by mechanisms that we think they're going to <br />fail by and cause environmental damage. The following impacts will occur: <br />a. This is going to give a black eye to the solution mining industry by affecting it <br />environmentally; <br />b. Development opportunities for nahcoGte recovery and involvement for investment in <br />the Piceance azea will be diminished;. <br />c. We're going to have regulators and environmentalists who aze going to step in causing <br />difficulties, not only for existing solution miners, but for new solution mining <br />development; and <br />d. Capital for solution mining will be hazder to come by. <br />Response: Based on the information provided in the application and the information received <br />during the public comment period, EPA has made a determination that operation of this project in <br />compliance with the conditions of the UIC Permit would be protective of all ground-water <br />aquifers. This determination is based on the location and properties of the injection zone, the <br />construction requirements for the solution mining wells and the comprehensive monitoring <br />programs. <br />The injection zone is located in the Parachute Creek member of the Green River <br />Formation. The mining will occur in the Saline zone portion of the Parachute Creek Member. <br />This zone is composed primarily of oil shale with nahcolite, dawsonite and halite. The injection <br />zone is not an underground source of drinking water (USDW), and would not be defined as an <br />aquifer due to the absence of ground water. The top of the mining cavities will be 150 feet or <br />greater below the top of the saline zonellower aquifer boundary (the Dissolution Surface). <br />The construction specifications require the longstring casing that extends to the top of the <br />cavities to be cemented to the surface. The Permit establishes specific requirements for ensuring <br />the integrity of each drilled well. The EPA has evaluated the proposed casing and cementing <br />program for the solution mining wells and has deterntined that the material and construction <br />procedures are adequate to prevent injection leaks. Once construction is complete, however, a <br />cement bond log will be run to assess the adequacy of the cement placed from the base of the <br />casing to the surface prior to obtaining authority to inject. When injection has commenced, a <br />temperature ]og will be run to ensure that there is no flow adjacent to the longstring casing. <br />