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NEWMON '. Newmont Mining Corporation <br /> 100 N 3r,Street <br /> PO Box 191 <br /> Sustainability and External Relations Victor..CO 8086080111 <br /> T 719-689-2977 <br /> F 719-689-3254 <br /> www.newmont.com <br /> SENT CERTIFIED, RETURN RECEIPT REQUESTED <br /> 7014-2870-0001-3417-6715 <br /> 1 December 2015 AUC'I) <br /> IRSO <br /> Mr. Timothy Cazier, P.E. DEC 0 7 2015 <br /> Environmental Protection Specialist <br /> Colorado Department of Natural Resources b111I�I M(XN L/WUTN <br /> Division of Reclamation, Mining and Safety Ift"OM3 <br /> Office of Mined Land Reclamation <br /> 1313 Sherman Street, Room 215 <br /> Denver, Colorado 80203 <br /> Re: Permit No. M-1980-244; Cripple Creek &Victor Gold Mining Company ("CC&V"); <br /> Cresson Project; —Notification of High Grade Mill (HGM)high pH water manage refinement <br /> Dear Mr. Cazier, <br /> In Section 6.5 Water Balance and Recycling of the Amendment 10 application it was predicted <br /> that ...approximately 60 gpm from the mill leach circuit will be pumped to AGVLF or SGVLF <br /> and either injected into the barren pipeline or to a designated drip tube distribution system. As <br /> the HGM has undergone commissioning, it has been necessary to refine this original prediction <br /> of volume, and experience working with the high pH water has led to an improved method of <br /> managing the water using deep injection rather than the surface drip system originally proposed. <br /> Based on operational experience with the HGM and practical options, it has been determined <br /> that approximate maximum flows of 500 gpm with an average of 100 gpm of water from the mill <br /> leach circuit is more realistic than the 60 gpm predicted in the A-10 application. This water will <br /> be pumped via a 4"HDPE line to AGVLF and injected into a pair of deep wells on the 9950' el <br /> bench(see attached Figure 1). Injecting the high pH water prevents it mixing with more neutral <br /> pH surface water and oxidizing in the atmosphere, both of which reduce the potential for <br /> precipitation. Injection also places the water deep into Phase 4 where it is more readily mixed <br /> with process solution. The injection wells will be operationally monitored for performance and <br /> rehabilitate/replaced when and if it is necessary over time. <br /> When we discussed the way forward on this change, you asked several questions on behalf of <br /> DRMS. These include the angle on the wells, precipitates, and rehabilitation of the wells. We <br /> have supplied those answers below. <br />