2018-03-26_REVISION - M1980244 - Laserfiche WebLink

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'1� NEW M O N T Newmont Mining Corporation Cripple Creek&Victor Gold Mining Company 100N3"St M-1980-244 - TR97 Victor, CO 80860 Compiled! www.newmont.com 5 TOTAL Violations! tcl, whe SENT CERTIFIED RETURN RECEIPT REQUESTED &CEIVED 7017 2400 0000 4077 7794 MAR 16 2018 March 22, 2018 AMS'NOMMLAWN 1NINGAIW 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: Permit No. M-1980-244; Cripple Creek&Victor Gold Mining Comm(CC&V): Cresson Project; Grassy Valley—Monitoring Well Installation—TR#97 Dear Mr. Cazier: Newmont Mining Corporation's Cripple Creek and Victor Gold Mining Company(CC&V)hereby submits to the Colorado Division of Reclamation,Mining and Safety(DRMS)the following Technical Revision(TR) 97 proposing the installation of one groundwater monitoring well in Grassy Valley. Background The East Cresson Overburden Storage Area(ECOSA)was originally permitted in Cresson Permit M- 1980-244 Amendment 9(Figure 1). The facility is unlined and was designed to allow precipitation to infiltrate into and through the facility to the underlying diatreme. Due to the variability of the alluvium ECOSA was constructed on, a seep has developed along the southeast toe of the facility(Figure 2). After discovery of the seep during a DRMS inspection,CC&V developed a plan to monitor the accumulation of fluid from the seep,and if necessary, convey the solution from ECOSA onto a lined facility internal to the site. On November 28,2017,Newmont personnel met with DRMS to discuss ECOSA and a methodology to convey fluid expressing from the seep into the diatreme. During this discussion,it was identified that the groundwater monitoring locations within Grassy Valley (GVMW-8A,GVMW-813,GVMW-22A&GVMW-22B depicted in Figure 3)are on the east side of Grassy Valley across the thalweg of the valley. DRMS requested the installation of a monitoring well on the west side of the valley,downgradient of the seep location. CC&V has agreed to the request and proposes a monitoring well be constructed downgradient of the identified seep location within Grassy Valley(Figure 2). The monitoring well is to be constructed within the alluvium and advanced to bedrock. Figure 4 includes a cross section(looking northwest)which depicts the currently understood geology of the area. Figure 5 depicts the cross section orientation.