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CNAP~ERFOUR. Responses to Public and Agency Comments Letter and i Comment No. Response intermediate casing would be cemented back to the surface with heat resistant cement (silica flour added). American Soda kuu used tremmie- line cementing with good results during the test phase. The principal benefit of the tremmie line method relates to cementing through lost circulation zones. The lower aquifer zone tends to be an area of lost circulation. Using a conventional cement job, the cement is forced up the annulus and there is potential for the cement to be :lost as it enters the lost circulation zone. Obtaining ahigh-quality cement job in and above a lost circulation zone can be difficult and methods to mitigate a poor cement job aze possible but limited. The tremmis line method allows the positive placement of the cement and also allows the placement of different strength cements (or cement mixes) at specific locations. During a conventional cement job, the bottom section of the hole is exposed to a high hydrostatic pressure due to the weight of the cement (14 to 15 poundslgallon). The hydrostatic pressure of the cement can break down the formation and the cement may not circulate properly. The tremmie line method places cement in lifts in the :mnulaz space between the casing and the wellbore. Using lifts minimizes the hydrostatic pressure placed on the formation by the weight of the cement. After each lift, the cement is tagged, the tremmie line positioned, and another lift is performed. This allows a controlled method to place the cement until complete cement fill is achieved. Tremmie line cementing is more costly and time consruning than conventional cementing. However, American Soda's experience at this site indicates that it produces ahigh-quality cement job and may be better in many instances than conventional cementing through the wellbore. The cementing program would be provided in the APD and approved by BLM on a per well basis. e. A cement bond log and a temperature log would be run to determine the adequacy of the cement job on the intermediate casing. If it is determined that the cement job is not adequate the BLM would require that American Soda perform remedial cement work to attain an adequate cement job. F-2.5 American Soda has not applied to the BLM to use the cavities for waste disposal. The recycled water to be used as the injection fluid is a weak brine and several streams from processing may be in the r~,cycled water. Based on the test phase data, American Soda does not intend to use the cavities directly for disposal of wastes. The recycled water would be the fluid used in mining and no provisions have been made for separate storage 4~