2017-09-14_REVISION - M1980244 (2)

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RECEIVED NEWMONT [ 0 NeHmont Mining Corporation �SEI� 4 � � �(apple Craek h ictor(,old Miring r:pd:r} 100 N';"S( DMSION OF RECLAMATION P() fA,r IQ MINING AND SAFETY `Icwn U0 W8t,0 %k�,N,neu moat com September 12, 2017 SENT CERTIFIED RETURN RECEIPT REQUESTED 7015 1660 0000 0779 9611 Mr.Timothy Cazier,P.E. Environmental Protection Specialist Colorado Department of Natural Resources Division of Reclamation,Mining and Safety Office of Mined Land Reclamation 1313 Sherman Street, Room 215 Denver, Colorado 80203 / Re: DRMS Permit No.M-1980-244; Cresson Proiect; Cripple Creek&Victor Gold Mining Company CC&V• —HGM to SGVLF Solution Line—TR#92—Response to Preliminary Adeauacy Review l/ Dear Mr. Cazier: On July 19, 2017, the Cripple Creek and Victor Gold Mining Company (CC&V) submitted Technical Revision No. 92 (TR-92) which proposes rerouting excess High Grade Mill (HGM) solution from the injection wells located on the Arequa Gulch Valley Leach Facility(AGVLF)to an infiltration gallery or into drip lines located on the Squaw Gulch Valley Leach Facility (SGVLF). On September 1, 2017, CC&V received the Preliminary Adequacy Review letter from the Division of Reclamation, Mining and Safety (DRMS). CC&V has reviewed DRMS' review letter; CC&V has included DRMS' questions in italics with CC&V response provided below in bold. A. Background (p. 1) — The text states the "chemistry of the solution is essentially the same as the solution circulating within the VLFs". Additional text on p.2 indicates placing the proposed 4-inch HDPE line "on lined facility its entire route" eliminates "any potential impacts to the environment". Furthermore, Attachment 2 shows two flatter sections of the proposed alignment(Approximately Station 3+50 to 4+00, and —9+25 to 10+00). On April 12, 2012 a spill occurred in the vicinity of the perimeter safety berm overlying the anchor trench at the toe of the Phase V VLF. The spill occurred in an area where the edge of the VLF liner is relatively flat (as is the pipe conveying process solution). It was later determined the manganese precipitate in the pipe may have contributed to restricting the flow causing the leak. The extent of the liner was also implicated. This leak did have the potential for environmental impact as the spill went off liner. Please discuss how this proposed pipeline, seemingly similar to a situation that did have potential for environmental impact is "eliminated" in this proposed change. CC&V Response: The release mentioned above occurred on the northwest side of Phase 5 adjacent to the crusher access road. There is a major drain tile in this area that collects pregnant solution from the whole northern end of Phase 5.When the release occurred the drain tile was partially exposed, allowing air into the system, thus increasing oxidation. The topography in this portion of Phase 5 is relatively flat,which has resulted in drainage issues. The slow moving or stagnant solution allowed manganese to precipitate. When the release occurred pregnant solution was backing up in the drain tile pipe and 1