2007-12-19_REVISION - M1988112 (12)

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respectively, with a corresponding above-grade (jurisdictional) storage capacity of 88.0 acre-feet. The maximum pool area (at elevation 8615 ft-amsl) is 9.7 acres. The statutory height at the maximum embankment section is 10 feet. The stage capacity and stage area characteristics for the East Pond are shown in Figures G.2-13 and G.2- 14, respectively. The pond storage capacity of the East Pond at the maximum pool elevation (8613 ft-amsl) and at the statutory ground elevation (8603 ft-amsl) are 70.9 acre-ft and 31.0 acre-ft, respectively, with a corresponding above-grade (jurisdictional) storage capacity of 39.9 acre-feet. The maximum pool area (at elevation 8613 ft-amsl) is 4.7 acres. The statutory height at the maximum embankment section is 10 feet. The stage-capacity characteristics for the ponds are summarized in Table G.2-1. From the results summarized in Table G.2-1, 2 feet of freeboard would be maintained in both ponds under average operating conditions while providing 182 acre-feet of storage. This will provide 13 acre-feet of contingency storage under average operating conditions. A review of available hydrometerologic data indicates the 100-year, 24-hour storm at the site would result in 2.7 inches of precipitation (NOAA, 1973). Upland storm water flow is routed around the irrigation ponds and only direct precipitation would contribute to the storage volumes in the ponds. With the design freeboard, there is ample capacity in the ponds to prevent overtopping under a 100-yr, 24-hr storm event. Excavation of the West Pond will result in approximately 148,000 cubic yards of excavated material that will be relocated to the Waste Rock B. Topsoil will be stripped from the 6-acre top surface of the Waste Rock B and stockpiled for reuse prior to relocation of excavated materials from the irrigation ponds. Placement of pond excavation material in the Waste Rock B facility will result in the overall height being raised by approximately 15 feet. Upon completion of the relocation, the outslopes of the excavation material will be recontoured to 3:1 (horizontal:vertical) or flatter. The excavated material surface will then be covered with a minimum of 12 inches of topsoil, and all disturbed areas in the Waste Rock B area will be revegetated. Battle Mountain Resources, Inc. 28 P.\Pmjwb\212-N,wv (SenLm,)\S=Luic\Permit Amendment- West Pit MamgemenAVS Report&PDFs\Tezt\Pe tAmeDI=n_vx.aw December 2007