2008-06-09_REVISION - C1980007 (3)

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Chapter 3 Alternative 2 Surface Water The reuse of the; previously constructed pad for the ventilation shaft/escapeway and road would likely have minimal direct effects on surface water quality. I:f raisedbore or blindbore shaft construction is used., any overshot waste rock generated would be handled subsurface and would have minimal direct effect on soil erosion and sedimentation. If conventional sink/line construction is used, surplus waste rock would be temporarily stored on the drill pad and eventually hauled out of the project area. This second type of shaft construction could directly affect surface water by erosion and sedimentation; however the shaft would be nearly 300 feet from the nearest surface water, and surface disturbances would be mitigated by interim reclamation and runoff control measures. The design criteria including soil salvage and soil. staging (Table 2-1), interim reclamation, drainage control measures for drill pads and road construction, road maintenance, engineered crossings, erosion control measures on steep slopes, etc. would generally be effective in preventing or limiting soil erosion, and sedimentation. Despite these practices, erosion, soil loss, and sediment transport from. newly disturbed areas would. still. directly affect nearby drainages. The degree of impact caused by sediment runoff upon surface water quality (turbidity and suspended solids), would be largely dependant upon its proximity of the disturbed areas to streams and the magnitude of runoff. Approximately 75 percent of the project construction disturbances would be outside any WIZ or similar surface water body, and these disturbed areas not located proximal to surface drainages would likely have minimal impact on surface water and riparian resources. ~i Modification of the access road to a light-use (low-volume) road once shaft and emergency structures are constructed would also lower the potential for direct impact. Final reclamation of the shaft .and escapeway will include sealing the airshaft and escapeway with concrete/steel structure 10 feet below ground surface and performing final. surface reclamations when no longer needed at end of life of mine (mine life estimated at 13-15 years). A total of 31 drill pads would be located in or adjacent to water influence zone (WIZ) (100 feet on either side of the stream) buffer zones. To access these drill pads, approximately 6.5 acres of new or upgraded road would occur within these buffer zones including 6 intermittent creek crossings and one perennial stream crossing. Construction in areas adjacent to a WIZ buffers would be reviewed on the ground by USFS persomlel to determine whether or not the WIZ would be affected and if additional mitigation measures should be developed/implemented. The potential for indirect surface water impacts due to the drilling, well completion, and maintenance of the MDWs is minor. The potential for small accidental fluid spills exists from drill rigs and support vehicles. However, proper transportation and handling practices and the use of staging areas would help to minimize the potential for accidents. Since most equipment operations would occur in the drill pad areas, any minor spills would be contained by drainage control berms in these areas. All drilling fluid and circulation additives that would be used are either naturally occurring inorganic or organic materials or biodegradable compounds. Loss or spillage of these materials would not adversely impact water quality. Grournd Water Minimal bedrock water is expected to be intercepted during the proposed drilling operations, however shallow colluvial or perched ground water could be encountered during drilling or road construction near • • 66 Deer Creek Ventilation Shaft and E Seain Methane Drainage Wells FEIS