2011-08-08_REVISION - M1977493 (33)

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• • Technical Revision (TR -18) Climax Molybdenum Company Environmental Protection Plan Permit No. M- 1977 -493 the water management and treatment system. The effectiveness of the Robinson, Tenmile, and Mayflower TSFs is self- evident. The Robinson TSF has been used since the mid- 1930s, the Tenmile TSF since the mid- 1950s, and the Mayflower TSF since the mid -1970s without failure. Each TSF contains major point and non -point source releases of potential contaminants from upstream areas including impacted seepages from the McNulty and North 40 OSFs, and potentially contaminated surficial run -off from haul roads, the pit area, and the yard areas around the mill facilities. The effectiveness of the Mayflower TSF (including the 5 Dam Seepwater Collection and Return System) in the Climax water treatment and discharge system has been discussed at length. Designated chemical storage EPFs within the mill all include secondary containment as described in Section T -3. T -5.5 Specif /c Environmenta /Protection Faci//tyMonitoring/A /arms The critical EPFs at Climax are regularly checked, inspected, or monitored either visually, analytically, or both by security and water treatment personnel that are on -site at all times. Occasional inclement weather can restrict access to some facilities for short periods of time. In the case of pump stations, mechanical and telemetric alarms also are operational should failures occur. These monitoring systems are discussed herein by EPF and watershed. System alarms for the critical EPFs are discussed in subsequent sections. Facility monitoring /alarms details are not included for potential future EPFs that have not been designed. T -5.5.1 Arkansas River Watershed 5 -Shaft Pump Station: The 5 -Shaft Pump Station is equipped with monitoring and alarm systems. In addition to these systems, the station is visually checked regularly. A groundwater piezometer (5 -Shaft Monitoring Well) has been installed adjacent to the pump station to monitor groundwater levels adjacent to 5- Shaft. Storke Wastewater Pump Station: The Storke Wastewater Pump Station is equipped with monitoring and alarm systems. As with the 5 -Shaft Pump Station, the Storke Wastewater Pump Station is checked visually by designated employees. T -5.5.2 Eagle River Watershed Robinson TSF and 1 Dam: As discussed previously, 1 Dam has been reconfigured, stabilized, and reseeded. Monitoring of this EPF is conducted visually by various mine personnel. Piezometers are utilized to monitor water levels in the dam. Robinson Lake and Dam: Visual monitoring of Robinson Lake is performed routinely by Climax personnel. When the construction of the Robinson Lake Pump Station is completed and the facility brought online, it will operate as the main level control for Robinson Lake. A water level indicator will be installed to continuously monitor the water level within Robinson Lake. The water level indicator will be connected telemetrically to the mill control room to provide immediate notification should water levels exceed set points for high water action levels. Robinson Dam is considered to be a jurisdictional dam by the Dam Safety Branch of the Colorado State Engineer's Office (SEO) and must therefore meet the dam safety and inspection requirements of the SEO's "Rules and Regulations for Dam Safety and Dam Construction." The Dam is inspected regularly by Climax personnel and generally once per year by SEO personnel. A total of nine piezometers are located in the Robinson Dam embankment. Climax personnel routinely monitor the piezometers and maintain a database of phreatic water levels. A foundation drain system is located on the right downstream abutment of the dam. The flow rate from the drain is monitored regularly by Climax personnel and recorded during the SEO's Dam Safety Engineer's inspections. A small collection pond near the toe of the dam also collects dam seepage. This EPP: Revision R1 T -29 July 2011