2018-08-22_REVISION - M1977493A - Laserfiche WebLink

Home Browse Search

Technical Revision (TR-28) Climax Molybdenum Company Environmental Protection Plan Permit No. M-1977-493 system. The Tenmile TSF is considered both a source of potential contamination and an EPF. The integrity of the TSF and 3 Dam provides containment of the tailing material. The Tenmile TSF also provides control for contaminants that might be released from upgradient sources. Seepage from the dam is routed to a collection pond and pumped back by vertical turbine pumps to the SDP or diverted to the water pool on the Mayflower TSF. This pumping system is located within the 3 Dam Pump Station below the TSF. The 3 Dam Pump Station is scheduled to be abandoned in the future since it will be covered by the growing Mayflower TSF. At that time, all seepage will report to the Mayflower TSF for Stage 1 water treatment. Mayflower TSF and 5 Dam: The last TSF downstream in the Tenmile Creek Watershed is the Mayflower TSF. This TSF and its dam (5 Dam), along with the 5 Dam Seepwater Collection and Pump System is the final water management control (excluding the PDWTP) on Tenmile Creek within the Climax property boundary. At the end of mining, the projected size of Mayflower TSF is approximately 900 acres. The Mayflower TSF was constructed in the mid-1970s. It was utilized for tailing deposition until Climax ceased mill operations. In the early 1990s, the beach areas of the TSF and 5 Dam were capped with rock and soil material excavated from the eastern edge of the TSF. A portion of this capping had been removed prior to the resumption of tailing deposition in mid-2014. To prevent dam failure, the Mayflower TSF also includes an emergency flood bypass tunnel (described in TR-21). As with the Robinson and Tenmile TSFs, the Mayflower TSF is both a potential source of contamination and a critical EPF. As a potential source, the Mayflower TSF contains tailing material that is considered potentially acid producing. It should be noted, however, that the historical use of this TSF strictly as a water treatment facility has served to add significant amounts of lime to the impoundment Another source of potential contamination is seepage emanating from the toe of 5 Dam This seepwater is slightly acidic with elevated sulfate and metals. As an EPF, the Mayflower TSF, including 5 Dam, is crucial. Mayflower TSF (as well as Tenmile TSF) also provides containment of contaminated materials or designated chemicals if they are accidentally released up-gradient of the TSF. In addition, the Mayflower TSF contains, mixes, and treats impacted waters from several historic mines and smelter sites as well as non-point run-off waters which contact mine wastes within a large portion of the historic Consolidated Tenmile Mining District. 5 Dam Seepwater Collection and Return System: The seepwater collection and return system below 5 Dam (Mayflower TSF) is an important EPF at the Climax Mine. Although it is component of the Climax water treatment and discharge system EPF, it is discussed again here as a specific EPF. Seepage from the dam is routed to concrete ponds. Collected seepage is pumped back by vertical turbine pumps to the 3 Dam Pump Station or the water pool on the Mayflower TSF. Both 3 Dam Pump Station and portion of 5 Dam seepage return line beneath Mayflower TSF are planned to be abandoned in the future. At that time the seepage will be routed around 5 Dam and discharged directly to the Mayflower water pool for Stage 1 treatment. The 5 Dam seepwater pumping system is located within the Mayflower Pump Station below the TSF. During upset conditions, seepage can be temporarily contained within the 5 million gallon concrete pond system. Containment for Designated Chemicals for Concentrate Production: The EPFs for the designated chemicals used for milling and production of concentrate at Climax include containment provided by enclosed buildings, tanks, bins, and sumps, singly or in combination. However, additional containment EPFs for designated chemicals include the Tenmile and Mayflower TSFs and the associated water treatment system. As stated previously, the mill site and its ancillary facilities are located within the upper Tenmile Creek watershed. Therefore, a release of a designated chemical or process waters not contained at the release site ultimately would be contained at the TSFs. TR-14 described the new mill and accessory buildings for use during resumed production, however the final design and layout of the mill and accessory buildings had not been fully developed at that time. TR- 14 designated the mill building as a location for several Environmental Protection Facilities (EPFs) associated with designated chemicals. Additional details of the mill facility have since been developed and general arrangement drawings of the mill and reagent storage and containment areas are provided EPP: Version R4 T-28 August 2018