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NUCLA PR NO. 2 <br /> comparison of predicted to actual pit inflow is not possible for two <br /> reasons. First, the Nucla Mine Permit Application did not contain a <br /> quantitative calculation for pit inflows. Secondly, pit pumps were not <br /> metered. Although all pit pumpage has been diverted into the NPDES 001 <br /> impoundment, which is continuously monitored, irrigation return for <br /> water from the contributing drainage area also is impounded in the 001 <br /> impoundment. The additional flow into the 001 impoundment precludes <br /> Peabody from indirectly calculating Nucla pit pumpage volumes. <br /> Comment: <br /> 6. The McWhorter analysis was run using a five-year mine plan. What <br /> schematic mine plan was utilized to produce the pit lengths? <br /> Response: <br /> A five-year mine plan schematic supplied by Mine Planning similar to the <br /> one shown on Exhibit 12-3, Operations Plan, was used to determine the <br /> inflow for the McWhorter analysis. The area used to determine the <br /> inflow was the width of a typical mine pit and the total length that is <br /> opened during a one-year period. <br /> Comment: <br /> 7. Figure 17-2, Page 17-12, shows a permit area which is not located <br /> anywhere near the current representation of the permit boundary and <br /> shows an east-west model pit. Do these variations from reality <br /> have any bearing on the results of this run? Were the <br /> potentiometric surface shown on Exhibit 7.2 and 7.3 used in this <br /> model southwest of Nucla or directly west of Nucla? <br /> Response: <br /> Based upon a phone conversation with Cathy Begaj at CMLRD (date 7/14) <br /> the figures in question were misinterpreted by the CMLRD staff. The <br /> permit area is correctly located. In addition, the potentiometric <br /> surface maps as referenced were used in the calibration of the MODFLOW <br /> model . <br /> Comment: <br /> 8. Are the MODFLOW grids representative of a rectangular pit, the <br /> permit area or something else? Do they have any relationship to <br /> Figure 17-2? <br /> Response: <br /> The mine pit was represented in the MODFLOW model as a rectangular set <br /> of grid cells comprising a total area of 1920 x 720 ft (1,382,400 ft2) <br /> near the center of the permit area. Each grid cell at the center of the <br /> permit area represents a 240 ft by 240 ft block. The mine pit <br /> 7 <br />