2012-12-07_REVISION - M1977307 - Laserfiche WebLink

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Response to DRMS Adequacy Review — Cotter CM -25 Mine Reclamation Plan Amendment Once active mining resumes at the CM -25 mine, additional stormwater structures will be constructed and left in place after final reclamation. The goal of these structures is to divert any offsite stormwater from coming into contact with the waste rock and to retain any stormwater runoff from the waste rock pile itself. Good housekeeping will be exercised at all times which include keeping the site free of debris, cleaning up any spills and repairing any damage to stormwater structures. 5. Addressing Rule 6.4.21(7) – The EPP states that a radiometric survey will be completed prior to mining in order to document baseline conditions at the site. Baseline conditions shall be established as part of this amendment process. Please conduct a radiometric survey of the affected area and submit the results to the Division along with an evaluation of the expected effectiveness of the proposed EPP, which specifically addresses the risks, from uranium, uranium byproducts, and any other radionuclides expected to be encountered during this operation, to human health, property and the environment. The baseline radiometric survey is included as Attachment 2 in this response to DRMS comments. Cotter procedures for separating ore from waste rock are designed to minimize the addition of uranium ore to the waste rock pile —an approach that makes sense from an economic and environmental standpoint. The EPP addressed several issues that evaluate the risks to human health and the environment. The potential of acid mine drainage from the waste rock piles was quantified by the SPLP tests that indicated this was not an issue. The hydrogeologic evaluation presented in the EPP showed that factors of low precipitation, low permeability, and geochemical conditions restricted potential leachate from the waste rock piles from impacting groundwater resources. A detailed Drainage Design Plan (Appendix III in the EPP) routes off -site surface runoff around the waste pile and captures and contains on -site runoff from a 100 -year 24 -hour precipitation event. 6. Addressing Rule 6.4.21 (8) (c) – The EPP states, on page T -9, that the geologic units in the area dip to the northeast. On page T -11, the EPP states that geological units dip to the northwest. The first paragraph of section 8.3.2 on page T -11 should read, "The geologic structure of the area is also important in predicting the direction of groundwater flow. CM -25 is located on the flank of the Paradox anticline with the geologic formations dipping to the northeast at 0.05 (ft/ft). Groundwater flow directions in the area are controlled by the dip of the rock and would flow in a similar northeast direction." 2