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Henderson Mine SPCC/MCP May 1999 • As shown in Figure 3, two fresh water reservoirs aze located in Woods Creek Valley. The Upper Urad Reservoir is located above the Upper Tailing Impoundment while the Lower Urad Reservoir is located below thd,~,ower Tailing Impoundment. Both reservoirs are owned and operated by the City of t~biden. To minimize impacts to water quality in Woods Creek, the creek flow from the Upper Urad Reservoir is diverted around the reclaimed tailing impoundments using lazge diameter concrete pipes. The pip.; beneath the Upper Tailing Impoundment discharges to the surface just upstream from Ruby Creek's dischazge point into the Woods Creek drainage. The combined flow of Woods Creek and Ruby Creek is then diverted through a pipe around the Lower Tailing Impoundment into the southwest corner of the Lower Urad Reservoir. The treatment plant discharges treated water directly into this diversion pipe (Outfall 005). 2.3 Spill History In the three yeazs preceding this update, there have been two reportable spi;ils at the Henderson Mine and Urad Minesite. The first spill occurred on May 1, 199"~ when a snow plow hit a cap on a buried water pipeline. Approximately 10,000 gallons of untreated mine water with a manganese concentration of 52 mg/1 was released. The incident was reported because this volume and manganese concentration of water constituted more than one pound of manganese. The water flowed overland across the face of the Lower Urad Reservoir Dam. No evidence could be found that this spill • reached Woods Creek below the reservoir. The pipe that was damaged was rep;iired and a temporary protective berm was constructed to prevent a reoccurrence of the incident. The pipe has since been replaced by a dual pipeline buried six feet below grade. The second spill occurred March 21, 1998 and involved a reported leak of PCB dielectric fluid from a transformer to a designed containment. Approximately 1.5 gallon, of fluid leaked into the containment structure. The azea was cleaned up in accordance with applicable EPA requirements. Since the operation began in 1976, only minor incidents have occurred and hive been reported to the Colorado Water Quality Control Division. Henderson maintains the capacity to react appropriately to hazardous material spills. It possesses the equipment, materials, trained personnel and response systems necessary to control and neuUalize the impact of accidental spills on neighboring environmental and water resources. Outside emergency response teams are also available, if required, from Rocky 1•~ountain Catastrophe (RMCAT~telephone: 1-800-930-001 I. LJ s