2016-06-09_REVISION - M1985029 - Laserfiche WebLink

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Gold Placer Disturbed Area Description Acreage Mining Cut Areas _ 52.4 Berm along Highway 9 2.8 ______ . .__.____-- —. _ ....--- —__...- - ..—____, __._..._-_--- __-- Prep Plant area,processing,stockpile areas 10.1 Pond 3 and 4 Area 3.60 .... _ .--- ----- -- ____. ....... Camp/Office/Fuel Storage Area 3.4 Site Roads 2.00 Total Disturbed Area 74.3 Some areas of the Gold Placer Disturbed Area have been removed (southern sediment ponds, now that Cut A performs the same task). The Mining Cut Areas category is unchanged by this technical revision. The only change to the mining cuts is their arrangement and orientation. See Map C-2. 4. The Operator committed to not exceeding a total disturbance of 34.1 acres for the gold operation under Amendment No. 5. Please confirm the total disturbance associated with the gold operation will not change as a result of redefining the mine phases. In the approved Amendment 5, the Division approved a worst case disturbed area of 62.8 acres. In that worst case scenario, 34.1 acres was the gold operation, with the remainder being the gravel operation. As shown in the Combined Permit Area table in Amendment 5, the peak gold operation is expected to be no more than 48.0 acres. This is still the case. The worst case disturbed area is also still anticipated to be 62.8 acres. S. The changes to the size of the phases are being made to account for MSHA requirements. Please specify the dimensions of the benches which will be used to minimize the height of the highwall. In addition,provide a brief description of how the benches will be constructed. The benches will be constructed by first excavating the upper bench out to the phase boundary. The depth of this bench will be approximately half of the depth to the bedrock. A second bench will then be cut to the bedrock. The bench height will average 20-30 feet based on previous excavations at the site. The berm (catch bench) left between the two benches will be height of an individual bench (20-30'). This will force the overall wall angle to be 11-1:1V or milder during excavation. 6. The Operator has proposed to change how stormwater will be managed at the site. Specifically, the Operator is proposing to remove a series of ditches and ponds. Please identify the ponds and ditches which will be eliminated. In addition, the Division requests a revised copy of the C-4 Hydrology Map, which was submitted under Amendment No. 5.The revised map should reflect the proposed changes, including the new diversion ditch.