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Response to DRMS Adequacy Review — Cotter JD -8 Mine Reclamation Plan Amendment <br />The analytical suite for the SPLP tests submitted in the June 1, 2011 EPP were <br />based on the CWQCC Basic Standards for Groundwater (Regulation No. 41). The <br />SPLP leachates were analyzed for all parameters listed in the DRMS adequacy <br />review (above) except hardness and phosphorus. Hardness is not required under <br />Regulation No. 41, but will be added to future geochemical testing suite. <br />Phosphorus will also be added to the analytical suite for all future SPLP testing. <br />The Applicant must also commit to sampling any seepage that might arise from ore <br />storage or waste rock piles, and the analyte list must be as stated above. Field <br />parameters such as pH and conductivity must be measured in situ. <br />Cotter response: Any seepage that is detected from the ore storage or waste rock <br />piles will be sampled for the analyte list stated, at a minimum, and field parameters <br />will be measured and reported. <br />7) Exhibit G states that the uppermost aquifer is the Entrada formation, and that it lies <br />between 120 and 270 feet below the ore zone. Also Table 20 on page 42 of the EPP <br />indicates that the Entrada "yields water." This formation is sufficiently close vertically to <br />mine activity that the protective measures of Hardrock Rules 3.1.7(1) (c), 3.1.7(2), 3. <br />1.7(3)(a), 3.1.7(7)(a), 6.4.21 (2), and 6.4.21 (8)(b) should apply. The Applicant should <br />submit plans for the characterization and protection of this water resource, including <br />installation of a monitoring well in the Entrada aquifer located in the vicinity of the mine <br />at a location where impacts are most likely to occur, baseline characterization as <br />required in Rule 6.4.21 (\I)(b), and future monitoring. <br />Cotter response: The existing workings are dry, and as such would represent five <br />quarters of sampling data for the current bedrock condition. Cotter proposes to <br />install a downgradient bedrock well at least six months prior to the advancement of <br />workings. Seasonal changes in water quality are not expected, due to the depth of <br />the monitoring well required to reach the saturated aquifer in the Entrada <br />Formation. The proposed bedrock monitoring well would be located within 500 feet <br />of exploration drill hole 79 -299E, at the approximate coordinates 1,056,850 East and <br />585,600 North (State Plane Colorado Central, NAD 27, feet). The expected depth to <br />water is 530 feet and the proposed total depth of the well is 570 feet, based on <br />information from exploration drill hole 79 -299E. The monitoring well would be <br />constructed using 4 -inch casing and 20 feet of screen. The monitoring well would be <br />permitted through the Colorado Division of Water Resources and will be drilled, <br />completed, and developed in accordance with standard environmental protocols for <br />monitoring well construction. Drilling would commence after the DOE stay on all <br />mining activities in the lease tract is lifted, after the location and well construction <br />are approved by DRMS, and at least six months prior to the advancement of the <br />existing underground workings. Accelerated monitoring would be conducted, if <br />necessary, to ensure that five samples have been conducted for valid statistical <br />analysis of baseline conditions. <br />Page 22 <br />