2007-05-04_REVISION - M1988112 - Laserfiche WebLink

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Preliminary Adequacy Issues May 4, 2007 San Luis Project, AM-02 Permit No. M-1988-112 Pape 3 According to the plans submitted under AM-02, the proposed pipeline will convey mine waste water to a storage pond. During irrigation season, the mine waste water will be drawn from the storage pond and utilized to irrigate three center pivot alfalfa fields. Total area for irrigation is represented as 452 acres. The application for AM-02 expands the permit area by approximately 139 acres (Figure F-5, Reclamation Plan for Roads and Pipeline) to include the storage ponds. However, no part of the 452 acres of irrigated field is included within the proposed permit area. The 452 acres area will be used by the operation as a work area to discharge, evaporate and consume the mine waste water, which resulted from the permitted mining operation. Pursuant to Rule 1.1{4), all land surfaces utilized by the operation as a waste discharge area constitute "affected land" and must be included within the permit boundary and addressed by the reclamation plan and financial warranty. Please amend AM-02 to declare all portions of the water management plan, including the irrigated fields and the locations of their associated irrigation equipment, as affected lands and addressed by the reclamation plan and financial warranty. 8. Discussions provided in AM-02 indicate that West Pit ground water has chemically equilibrated at or better than pre-mining groundwater quality. Such discussions refer to two documents, one having been generated by the DRMS, dated September 14, 2005, and the second being a Technical Memo #212100 from Telesto, dated January 3, 2004, Both documents acknowledge that the groundwater chemistry conditions depend upon maintenance of the groundwater elevation within the backfilled West Pit: Apparently, minor fluctuations in groundwater elevation can result in degraded water quality with elevated constituent concentrations than currently exist. The application indicates that the Applicant will maintain the ground water elevation by pumping. Pursuant to Rules 6.4.7(2)(c), 3.1.5(5), 3.1.5(10), 3.1.5(11), 3.1.6 and 3.1.7, AM-02 shall demonstrate how the Applicant intends to dewater and/or maintain precise groundwater elevations for the West Pit, in a manner that prevents unauthorized release of pollutants to the surface and groundwater systems and minimizes disturbances to the prevailing hydrologic balance of the affected land and of the surrounding area for the entire period of time that pumping will occur to support mining and reclamation activities. 9. The plans for the proposed 21,472 foot long pipeline indicate that the pipeline will have at least five drain valves located at low points in the pipeline to allow full drainage of the pipeline, as necessary during operations. Pursuant to Rules 3.1.5(11), 3.1.6, 3.1.7, 6.4.7, 6.4.20(8) and 6.4.20(9), AM-02 shall include groundwater monitoring sufficient to adequately characterize baseline conditions for the entire pipeline corridor and demonstrate how unauthorized release of pollutants to the surface and groundwater systems will be prevented, and how disturbances to the prevailing hydrologic balance of the affected land and of the surrounding area will be minimized for the entire period of time that the pipeline will be utilized to support mining and reclamation activities ~ Also, please describe how the water drained from the pipeline will be managed, e.g., will the water be contained and transported to the storage pond, or will it be land applied at the drain location? The DRMS would be concerned with land application of drained water, particularly given the close proximity of irrigation ditches to the drain locations.