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Response to DRMS Adequacy Review — Cotter CM -25 Mine Reclamation Plan Amendment <br />Cotter will at a minimum inspect all structures one to two times per week when the <br />mine is active and one to two times per month when the mine is inactive. <br />12. Addressing Rule 6.4.21 (18) (b) — Please describe the measures Cotter Corp. intends to take <br />to prevent wildlife from coming into contact with uranium, uranium by-products or any <br />other radionuclides. <br />The Colorado Parks and Wildlife (CPW) was informed of Cotter's intent to mine <br />and store uranium onsite. It did not recommend any additional measures to protect <br />wildlife from coming into contact with naturally occurring uranium ore, uranium <br />by- products or any other radionuclides. <br />13. This exhibit [Geotechnical Stability Exhibit] states that the waste rock will be added to the <br />waste pile in lifts and then compacted Please it form the division of the thickness of the lifts <br />and the compaction method(s) to be used <br />The waste rock pile at CM -25 will be constructed in lifts approximately one to three <br />feet thick. Each lift will be wheel rolled for compaction. <br />14. Please it form the Division of the necessary amount of compaction for the waste rock pile, <br />and the operators plan for insuring that necessary compaction of the waste rock is achieved <br />Compaction is only one of the eight parameters used in calculating the angle of <br />internal friction for the soil stability of the waste rock pile. The factor of safety is a <br />function of the angle of internal friction for the soil and the slope angle relative to <br />the horizontal. The factor of safety for the waste rock pile at CM -25 was calculated <br />to be 1.678 which is greater than the recommended 1.4 parameter for the safety <br />factor of permanent slopes. <br />This was a conservative calculation and it is unlikely, even if the degree of <br />compaction is not optimal, that the slope would be unstable at 2H:1V. The method <br />of plug dumping does, however, result in a fair amount of compaction which will <br />assure a stable slope based on the factor of safety calculation. <br />The method for ensuring proper construction and compaction of the waste dump <br />will be by visual inspection of the maximum lift thickness and observation of wheel <br />rolling each lift by the operator. <br />15. Please inform the Division of the maximum anticipated total thickness of the waste rock pile. <br />See #1. <br />4 <br />