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8 <br />Response to DRMS September 25, 2009 Letter Powertech (USA) Inc. <br />14. Powertech stated in since withdrawn modification MD-02 to prospecting <br />notice P-2008-043 that it has done preliminary hydrogeologic modeling and water <br />production calculations for the strata to be investigated by the proposed pump <br />test. DMRS has further discussed with Powertech that data collected during <br />development of recently drilled wells in Section 33 has allowed for refinement of <br />the modeling and calculations. This information will be useful in determination of <br />whether or not pump test water can be injected into the A2 Sand with assurance <br />that impacts to other water bearing strata are sufficiently minimized, and must be <br />provided. <br />Response: <br />Powertech has not performed groundwater modeling for the A2 Sand, but has <br />carried out a series of Theis simulations of the pressure response to pumping to <br />estimate pumping rates and duration for the proposed test. These simulations <br />were performed to match the observed drawdowns during development of the <br />recently completed A2 wells and the results from the previous Section 33 <br />pumping tests. <br />The results from the Theis simulations for the well development scenario and <br />from the previous pumping tests are consistent and indicate the order of <br />magnitude of hydraulic conductivity and storativity. The results for the best fit <br />analysis are shown below. <br />Powertech (USA), Inc. - Centennial Section 33 Pumping Test (Theis Simulations) <br />Trial #11b <br />K = 2.05 fVday <br />S = 4.18E-05 <br />Q = 10.0 gpm <br />H = 31 ft <br />Observation Well Distance (feet) <br />Pump Pump 0.5 100 250 500 1800 3600 <br />Time Time Drawdown Drawdown Drawdown Drawdown Drawdown Drawdown <br />(hours) (days) (ft) (ft) (ft) (ft) (ft) (ft) <br />1.0 0.0 31.90 6.49 2.54 0.54 - - <br />1.5 0.1 32.88 7.43 3.34 0.98 - -- <br />2.0 0.1 33.57 8.11 3.94 1.37 - - <br />6 0.3 36.22 10.72 6.39 3.34 0.10 - <br />12 0.5 37.89 12.38 8.01 4.82 0.47 - <br />24 1.0 39.56 14.05 9.66 6.39 1.26 0.10 <br />48 2.0 41.22 15.71 11.31 8.01 2.40 0.47 <br />72 3.0 42.20 16.69 12.28 8.97 3.18 0.88 <br />A ff*