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Colowyo, C1981-019, PR3 adequacy 7 February 25, 2011 <br />Rule 2.05.3(4) 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 rerun 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 />Rule 2.05.3(6) Overburden <br />1. Please assure that appropriate detail required by Rule 2.05.3(6) is included in the Operation and <br />Reclamation plan. Discussion of the pit dimensions, swell factor and blasting detail was not <br />found in Section 2.05.3(1) Operation Plan, or Section 2.05.3(6) Overburden of the PR3 <br />application, nor was there a discussion of where this information could be found in the <br />application. Please provide the detail required by Rule 2.05.3(6). Please state which seed mix <br />CCC will employ for temporary overburden stockpile stabilization (Collom-Rule 2, page 99). <br />Rule 2.05.4(2)(b) Reclamation Costs and Rule 3 Performance Bond <br />Colowyo Coal Company has not provided a reclamation cost estimate for the Collom expansion area at <br />this time. As mine plan details are finalized, a reclamation cost estimate is required to be submitted <br />and incorporated into the permit.