2015-08-24_ENFORCEMENT - M2004031

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isolate mine pits from surface water systems. • In accordance with the approved mining and reclamation permit, a slurry wall was constructed around the mine excavation area between May and August of 2005 to reduce inflows of groundwater and facilitate more efficient dry mining of the site; however, the mine excavation is not isolated from groundwater nor has Al yet sought approval of the slurry wall from the Division of Water Resources ("DWR"). • Repairs to the slurry wall are being made to assure the lined pit will meet DWR standards referenced in the State Engineer Guidelines for Lining Criteria for Gravel Pits. When the slurry wall repairs are completed and sand and gravel mining also completed, AI will conduct DWR's required 90 day leak test and submit the leak results and liner summary to DWR for determination as to whether or not the slurry wall meets its standard for approval. This is the regulatory process which would be anticipated as part of the approved reclamation plan. • DRMS currently holds a financial warranty for installation of the slurry wall that meets the DWR requirements. Next the Division denial of the proposed TR -05 on the basis that it substantially alters the approved reclamation plan and fails to demonstrate compliance with Rule 3.1.6(1)(a) which provides for compliance with applicable Colorado Water laws and regulations governing injury to existing water rights, is also incorrect for a number of reasons including: • Al is in compliance with the Division of Water Resource requirement of an annual "substitute water supply plan" and the Operator is in compliance with a Corps. of Engineer's Wetland Mitigation Plan. • Until such time as the DWR issues its approval of the slurry wall liner, depletions from the groundwater exposure is managed through the Operator's approved "temporary substitute water supply plan," including metering and accounting for waters discharged from the pit. This plan is reviewed annually with the DWR and is amended if necessary between plan year approvals. The 2015 SWSP has already been amended to include additional groundwater surface exposure. • The DWR review and approval process for the slurry wall following the leak test, will set forth the requirements for reservoir operations, including measuring and accounting for all water inflows and outflows for the liner enclosed area, and will assure the reclaimed Hazeltine Mine will continue to remain in compliance with Rule 3.1.6(1)(a). This process accommodates both DRMS and DWR's regulations in accordance with the Memorandum of Understanding of April 26, 2005 between these two agencies. • Water discharges during mining and until permit is released, are managed through existing approved discharge points regulated by the 4