1995-11-29_REVISION - M1977493 - Laserfiche WebLink

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Letter to Jay Jones -4- November 29 1995 in terms of the nature and orientation of fractures, joints and faults. Any significant adverse orientation of rock structures, i.e. , structures dipping into the pit, must be demonstrated to be stable over the long-term. The effect of any highly fractured or altered rock that could affect deep-seated pit wall stability may also have to be considered. (c) A demonstration of tailing embankment stability for Robinson, Tenmile, and Mayflower impoundments will be required. For static stability demonstration, please provide limiting equilibrium analyses based on impoundment configuration, physical characteristics of the tailing including undrained shear strength, and pore pressures. Provide details on instrumentation and monitoring that may be necessary to track the stability of the tailing impoundments. A demonstration that the tailing impoundments will be stable in the event of seismic shaking that has a reasonable probability of occurrence will also be required. (d) Documentation in the Climax Mine Reclamation Permit file indicates that embankments for Eagle Park Reservoir, Robinson Lake, Chalk Mountain Reservoir, and Buffehr Lake are under the jurisdiction of the Office of the State Engineer, and as such, no further demonstration of the stability of these structures will be required. Is the clear water or retention pond below the Mayflower water treatment plant permitted by the State Engineer? If not, a stability demonstration may be required. 10. Rule 6.4. 19 (7) (f) requires a demonstration that containment facilities shall be of adequate size to provide sufficient reserve capacity to prevent a release of designated chemicals or toxic of acid-forming materials from design storm events plus operational water volumes during worst case conditions as specified by the Division. The following information or clarifications will have to be provided to satisfy this regulation: (a) In Exhibit G of the 1989 Climax Mine permit amendment, it is stated that designs for tailing impoundment flood control structures in the reclaimed configuration will not be available until future mine operations are closer to final termination, although some description of possible flood management facilities has been provided in Climax's Reclamation Bonding Cost Calculations submittal to the Reclamation Permit dated March 31, 1994. It is the Division's view that design and construction of tailing impoundment flood control facilities will have to be conducted in accordance with the terms of Rules 7.3 and 7.4 of the Mineral Rules and Regulations, however, submittal of the designs will not be required until operations are closer to final termination. (b) Regardless of the finding that final design of tailing impoundment flood control facilities will not be required until a