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Mayday Mine and Mill Site, Wildcat Mining Corporation, 110(2) Permit Amendment <br />Exhibit C <br />Based on the testing done to date and the lack of impact from historical tailings, it <br />appears that the waste rock managed at the Mayday mine will not impact surface water. <br />However, additional static tests will be conducted during mine development activities <br />(one sample per 5,000 cubic yards mined or quarterly whichever occurs first) to <br />determine if the leach will pose an environmental concern. <br />Since current tests suggest waste rock or ore is not toxic or acid producing, liners will not <br />be used. If future static tests determine the rock is acid producing, 60 mil HDPE storage <br />liners will be installed to mitigate potential concerns related to potential leachate <br />migrating from the waste or ore storage piles. <br />Two groundwater monitoring wells will be located down gradient of the mine operation <br />to demonstrate compliance with existing groundwater quality standards. Well No. MD -1 <br />will serve as the water quality point of compliance for the Mayday Mine and Mill <br />whereas well No. MD -2 will be located at the base of Mayday mine bench No. 2 (See <br />Exhibit E -6 for well location; Rule 3.1.7 (b) and 3.1.7(7)) to determine if water quality is <br />affected by water infiltrating through the bench. <br />Groundwater monitoring wells will be constructed in accordance with Colorado State <br />Engineers permit requirements. Wells will be sampled in accordance with Standard <br />Operating Procedures (SOPs) outline in Exhibit C -5). Groundwater monitoring wells <br />will not be completed or used for monitoring if water is not is encountered 10 feet below <br />the surface level of the La Plata River (DRMS Correspondence to Wildcat Mining <br />Corporation, March 7, 2007 from Ms. Kate Pickford). If no groundwater is encountered <br />in the monitoring wells, the point of compliance will be located at the adit drainage <br />discharge point. Water quality samples will be obtained the second quarter of 2010 and <br />quarterly thereafter. Results will be summarized in Wildcat's annual DRMS report. The <br />sampling analytes to be tested, including explosive residues are presented in Table C -5. <br />Based on existing data, because all mining will occur above the water table and acid rock <br />drainage has not been identified after decades of mining, no impacts to groundwater <br />quality or quantity are predicted or anticipated from the mining and milling activities. <br />(Rule 6.3.3(2)(b) and (d)). <br />To mitigate potential surface water impacts, Wildcat's storm water and maintenance <br />mitigation plans are designed such that surface or groundwater discharges are not <br />anticipated to occur. The closest surface water receptor, the La Plata River, has water <br />quality concentrations that exceed aquatic life criteria for Cu, Pb and Ag (Exhibit B — Site <br />Description), indicating degraded stream quality. Additionally, the placement of any <br />waste rock stockpile at a discreet distance from the river, as well as the minimal volume <br />of waste rock to be disposed at any given time (less than 5,000 cubic yards for periods up <br />to 3 months) will aid in preventing surface water quality impacts. In areas where rock <br />will be stored for periods exceeding three months or exceeding 5,000 tons, a perimeter <br />berm at least two feet high will be constructed to contain sediment and water that could <br />potentially erode the stockpile. The berm will also serve to some degree as a visual <br />impact barrier from the stored material. Additional measures for protective handling of <br />waste rock are described in Section (k) below. <br />0. March 12, 2010 Amendment M- 1981 -185 <br />