2007-12-19_REVISION - M1988112 (12)

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The general layout of the irrigation ponds is shown in Figure G.2-4. Two ponds will be constructed to store water during the non-irrigation season. One pond (the West Pond) will be constructed northwest of the existing water treatment plant in the vicinity of the existing holding pond. A second, smaller pond (the East Pond) will be constructed to the east of the existing water treatment plant. Both ponds will be drained by the irrigation pipeline located adjacent to the Rito Seco Road to provide irrigation water to the ranch (Figure G.2-4). Details of the two irrigation ponds are shown in Figures G.2-5 through G.2-10. The West Pond will be constructed by excavating approximately 160,000 cubic yards of material, up to 14 feet deep into the existing pit backfill, and placement of a compacted earth fill perimeter berm as shown on Figure G.2-5. Borehole logs for wells drilled in the West Pit footprint indicate the upper 15 to 60 feet of pit backfill consists of Santa Fe Formation material that contains abundant carbonate minerals. Therefore, the excavation materials are expected to be non-reactive. Approximately 12,000 cubic yards of excavated material will be used in construction of the perimeter berm and the remaining 148,000 cubic yards will be placed on Waste Rock B within the existing mine permit area. The West Pond will consist of 9 to 10 feet of above-grade storage impounded by a perimeter embankment, and approximately 11 feet of below-grade storage created by excavating the pond interior below the existing ground surface. The pond embankment will have a crest elevation of approximately 8615 feet above mean sea level (ft-amsl) with a statutory ground elevation at approximately 8605 ft-amsl, and a bottom sloping toward a sump area at elevation 8594 ft-amsl. Relevant West Pond cross sections are shown in Figures G.2-6 and G.2-7. Drainage from the West Pond will be provided by a gravity-flow outlet pipe that ultimately leads to the center pivot irrigation system at the ranch. This outlet pipe will be located at or above the statutory ground elevation (approximately 8605 ft- amsl). The outlet pipe will flow by gravity under positive-head conditions when the pond water level is above an elevation of 8605 ft-amsl and will operate as a gravity- siphon when water level is below this elevation. The pond interior will be covered Battle Mountain Resources, Inc. 26 P.\Pmjmts\212-N.-.t(S-Lws)VSed.uis\Po-.it Amendment - West Pit MmttW=ot\V5 Report At PDFs\Text\PetmitAmedmem_v5c.dm December 2007