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Colowyo, C1981 -019, PR3 adequacy No. 3 <br />July 22, 2011 <br />Map 2913 appears to indicate that the X Pit will be entirely backfilled to grade by 2017. <br />However, the temporary spoil pile, which covers the southern portion of the pit, is not <br />scheduled for removal until the end of mining. Fig. 2 shows the Sump superimposed on the X <br />Pit shell, but does not address the condition that would exist if and when the pit is backtilled <br />with spoil and brought to final grade, nor does it show the presence of the temporary spoil pile. <br />Map 29C shows the temporary spoil pile superimposed upon the X Pit shell, but the southern <br />portions of the shell (beneath the pile) are not shown. <br />Please provide a clear narrative (with accompanying details on the maps, as appropriate) of the <br />proposed process: from excavation of the Sump, through mining of Little Collom X Pit, <br />phased construction of the temporary spoil pile, backfill of the Little Collom X Pit, and final <br />reclamation. <br />Item is resolved. <br />Rule 2.05.30) Ponds, Impoundments, and Diversions <br />The application includes a plan to use an in -pit sump in combination with a large sediment pond <br />located below all mining within Collom Gulch. Geotechnical analyses for the pond were included <br />with the application. In general, the Division finds the plan adequate. However, based on recent <br />information regarding changes to the mine plan in the northern portion of the proposed permit area <br />due to Federal coal lease issues, runoff and sediment modeling will need to be ream for the <br />proposed worst case disturbance. Other issues that were identified during the review are as <br />follows: <br />• Some of the secondary drainages appear to be improperly located with regard to the post - <br />mining topography. <br />• Disturbed areas are shown downgradient of sediment control ditches. <br />• It is not clear, given the timing of mining and reclamation, how reclaimed areas in the Collom <br />Lite pit will be routed around the temporary spoil pile that will block Collom Gulch. <br />Reclaimed areas in 2016 and beyond in the Collom Lite pit are not shown being diverted <br />around the temporary spoil pile. Discussions with representatives of Colowyo indicate that a <br />sediment pond immediately downgradient of the Collom Lite pit may be proposed. <br />1. Please review the drainage and sediment control plan over the life of the mine and ensure that <br />all disturbed areas will be routed through the sump /sediment pond system as stated in the <br />permit text narrative under Rule 4. <br />The application remains inadequate. Please review the drainage and sediment control plan over <br />the life of the mine and ensure that all disturbed areas will be routed through the sump /sediment <br />pond system as stated in the permit text narrative under Rule 4. Numerous disturbed areas <br />(topsoil stockpiles excluded) we shown on maps outside of (downgradient) from ditches <br />diverting water through the designed sediment control system. Small areas outside of the <br />