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Colowyo, 01981 -019, PR3 adequacy No. 3 11 July 22, 2011 <br />the valley fill water before mixing (based on Table 2.04.7 -41), and 3,000 mg/1 for the spoil <br />leachate (based on the Streeter well TDS noted on page 119 of the Rule 2 section of Colowyo's <br />PR -02 volume). <br />10. Please provide a calculation of potential spoil spring discharge from the downdip end of the <br />spoil in Little Collom X Pit that will result from snow melt and rain infiltrating from the surface <br />into the spoil. <br />No additional response is necessary, based on the current calculation of the spoil spring <br />discharge from the Cullom Lite Pit. <br />Rule 2.05.6(3)(b) Hvdroloeic Controls <br />The applicant has presented a plan for monitoring surface and ground water in accordance with Rule <br />2.05.6(3)(b)(iv). Any deficiencies with regard to the plan are noted under Rule 4.05.13 below. <br />2. Please revise the prediction of spoil spring discharges to the surface (Section 2.05.6(3)(b(iii)) <br />to reflect the requested calculations of annual pitwall seepage. <br />AS preciously rcqucstc(, pkesc add to the analysis (eunrontly on page 133) a calculation of <br />annual pitwall seepage at the downdip end of Collom Lite Pit. In the analysis, please predict <br />the spoil spring discharge rate by subtracting pitwall seepage fiom pit inflow. This method of <br />analysis is shown at the end of the attached Exhibit A. <br />Please revise the paragraphs at the bottom of page 138 and the top of page 139 to reflect the <br />0.52 cfs average spoil spring flow that is predicted on pages 136 through 138. Those pages <br />have recently been revised to show possible spoil spring flow from the Collom Lite Pit of 0.52 <br />cfs, calculated as follows: surface infiltration into spoil 47,255 efd (28,255 + 19,000), minus <br />pitwall seepage 2,016 cf /d, equals spoil spring discharge 45,239 of /d (which converts to 0.52 <br />cfs) . <br />Please delete the following two sentences from Rule 2, page 136, as they contradict the 0.52 cfs <br />spoil spring discharge to the surface: "It is very unlikely that groundwater resaturating the <br />reclaimed pit will accumulate to an elevation high enough to cause it to discharge to the valley <br />fill or to the surface in Little Cullom Gulch That could occur only if the capacity of the bedrock <br />units down -dip of the reclaimed pit to transmit groundwater flow were to be diminished <br />compared to the premining condition." <br />Rule 2.10 Maps <br />