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COLORADO <br />® Division of Reclamation, <br />Mining and Safety <br />Department of Natural Resources <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br />March 9, 2015 <br />M.L. Richardson <br />Asphalt Paving Co. <br />14802 W. 44`h Ave. <br />Golden, CO 80403 <br />RE: Ralston Quarry; DRMS File No. M- 1974 -086; Amendment No. 3 (AM03) —Adequacy <br />Review No. 2 <br />Dear Ms. Richardson, <br />The Division has identified several other comments and questions that must be addressed prior to <br />the Division's decision due date. Please be advised that if you are unable to satisfactorily <br />address any concerns identified in this review before the decision date, it will be your <br />responsibility to request an extension of the review period. If there are outstanding issues <br />that have not been adequately addressed prior to the end of the review period, and no <br />extension has been requested, the Division will deny this application. <br />1. The Applicant has stated the water at the bottom of the quarry is from stormwater runoff and <br />will evaporate and/or infiltrate into the ground within 72 hours of being captured. The <br />Division disagrees with this assertion. Please demonstrate how the quarry which has been <br />shown to have a low enough hydraulic conductivity to act as a water storage reservoir will <br />allow infiltration of stormwater in a 72 hour period. Otherwise provide a plan for releasing <br />the stormwater to the natural drainage system through pumping or other means. The <br />Applicant should note that any proposed plan for discharging stormwater must be in <br />compliance with the Operator's existing stormwater discharge permit. <br />2. The Summary of Groundwater Conditions at Ralston Quarry letter from Brierley Associates <br />indicates groundwater was observed within several- of the boreholes at depths between 6 to 9 <br />feet below the ground surface. Brieley Associates concluded the groundwater observed <br />within the boreholes is isolated from the regional groundwater table. The Applicant has <br />stated groundwater will not be exposed during the course of mining. If groundwater was <br />observed 6 to 9 feet below the ground surface, then groundwater will be exposed during the <br />mining operation. As such, the Operator would be responsible for replacing all evaporative <br />depletions associated with exposing groundwater, regardless of whether the water is a part of <br />a localized or regional groundwater table. In addition, if groundwater has the potential to <br />flow into or out of the pit, then the suitability of the quarry as an unlined reservoir is called <br />into question. <br />�w OF cOt0 <br />Q <br />I vi O <br />1313 Sherman Street, Room 215, Denver, CO 80203 P 303.866.3567 F 303.832.8106 http: / /mining.state.co.us * * <br />John W. Hickentooper, Governor I Mike King, Executive Director I Virginia Brannon, Director * 1g76 * <br />