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Response to DRMS September 25, 2009 Letter Powertech (USA) Inc. <br />11. Discussion on page 8 of the Section 33 Pumping Test Plan under the <br />heading "Produced Water Disposal" raises the following issues: <br />a. The Pumping Test Plan states that Powertech will demonstrate through <br />Mechanical Integrity Testing that there is no potential for injectate to flow <br />from the well into the Laramie Formation where the well passes through <br />that formation. MD-03 lacks discussion of how it will be assured and <br />demonstrated that injectate will not flow into strata above or below the <br />injection well screened strata after it is discharged to that strata, via either <br />natural or manmade (e.g., other wells) pathways. <br />b. The Pumping Test Plan states that the injection well is not expected to be <br />operated under pressure but allows that the injection might be pressurized <br />as needed. If the injection is pressurized, the potential for injectate to flow <br />into other water bearing strata above or below the screened interval is <br />increased. If the injection proceeds under atmospheric pressure only, it is <br />unlikely that flow paths other than those occurring under natural conditions <br />in the A2 Sand will develop, but the development of such new paths even <br />under atmospheric pressure alone cannot be ruled-out. <br />In order to address issues 11.a and b, Powertech may choose to commit to <br />storing the pump test water in Baker Tanks until the pump test data are analyzed <br />and a demonstration can be made that the A2 Sand is sufficiently contained to <br />allow pressurized injection without migration of injectate into overlying or <br />underlying strata. However, it is possible hydraulic connection between the A2 <br />Sand and other strata via open or ineffectively plugged wells will not be detected <br />during the pump test. This is particularly true if injectate were to flow along a <br />leaky well and into a lenticular water bearing strata in the Laramie Formation in <br />which none of the pump test monitoring wells have been screened. See item no. <br />12 below for further discussion of this issue. Another option would be for <br />Powertech to combine existing available information with a commitment to inject <br />at or slightly above ambient A2 Sand pressure to demonstrate that injectate will <br />not migrate into overlying and underlying strata, at least not any more than A2 <br />water would migrate under natural conditions. Alternatively, DRMS will review <br />any other proposals Powertech may offer to address these issues. <br />Response: <br />Based on previous pumping tests conducted by Powertech in Section 33 and the <br />observed aquifer response during development of pumping well PW-1, it is <br />estimated that PW-1 can be produced at a sustainable rate of 8 to 10 gallons per <br />minute for the planned test duration of 3 to 5 days. Based on the preliminary <br />estimates of transmissivity and storativity for the A2 Sand, the drawdown in the <br />pumping well at the end of 72 hours of pumping at 10 gallons per minute is <br />estimated to be substantially less than 100 feet. <br />