2011-08-08_REVISION - M1977493 (33)

Home Browse Search

• • Technical Revision (TR -18) Climax Molybdenum Company Environmental Protection Plan Permit No. M- 1977 -493 • 5 Dam Seepwater Collection and Return System; • EPFs for Designated Chemicals for Concentrate Production; • OSF Water Management Controls; • PDWTP; • Containment for Water Treatment Chemicals; and • East and West Interceptor Systems. New TDL: Tailing delivery and deposition for future mine production will utilize the existing Tenmile and Mayflower TSFs. As presented in TR -14, the installation of a replacement 36 -inch diameter high- density polyethylene (HDPE) TDL has begun from the mill discharge sump to the Tenmile TSF. The TDL will generally follow the alignment of the existing ETDL. The portion of the existing 42 -inch diameter reinforced concrete pipe (RCP) ETDL from the SDP to the Mayflower TSF may be evaluated for rehabilitation and use or may be replaced to convey tailing from the Tenmile TSF to the Mayflower TSF. ETDL: The existing ETDL is planned to convey impacted water sources to the SDP and to serve as an emergency tailing conveyance line should the main delivery line from the Mill to the first discharge point have to be taken out of service for a short period. This line is constructed of 36 -inch and 42 -inch RCP that isolates the impacted water from the environment until it is delivered to the SDP or deposited in one of the TSFs. Where grades are excessive, concrete drop structures are installed. The tailing delivery system is shown in Figure AM -06- T-01 Robinson TSF and 2 Dam: As discussed in Section T- 5.2.1, the Robinson TSF encompasses approximately 650 acres. 1 Dam and a small portion of the southern part of this TSF are located in the upper Eagle River Watershed and are discussed in Section T -5.2. The remainder of the TSF and 2 Dam are within the Tenmile Creek Watershed. The Robinson TSF contains mill tailing material. As discussed in Section T- 5.2.1, tailing material from the Climax mill circuit is recognized as potentially acid producing. The Robinson TSF has been decommissioned and, as noted previously, is in the final stages of closure reclamation. However, even when reclaimed, Robinson TSF remains both a potential source of contamination and an important EPF. Tenmile TSF and 3 Dam: The Tenmile TSF, including 3 Dam, currently encompasses approximately 620 acres and is located adjacent to and just downstream of the Robinson TSF. Once Tenmile TSF has reached its planned capacity of tailing material, it will encompass approximately 650 acres. The Tenmile TSF was constructed in the 1950s and contains tailing material that, as discussed previously, is considered acid producing. Future operations at Climax will first utilize the Tenmile TSF for tailing disposal. Approximately 29 million tons of additional tailing may be deposited in the Tenmile TSF. Mill tailing in slurry form is delivered to the TSF by the TDL. Clarified water is removed from the TSF through a decant system at Tenmile Decant via the Tenmile Tunnel (to the Robinson Lake or Mayflower TSF as discussed in Section T- 5.2.1). A water pool is maintained at the upstream end of the Tenmile TSF for process water storage, storm water management, and as the first stage in the water treatment 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. 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) currently encompass approximately 380 acres and along with the 5 Dam Seepwater Collection and Pump System is the final control on Tenmile Creek within the Climax property boundary. At the end of mining, the projected size of Mayflower TSF is approximately 900 EPP: Revision R1 T -24 July 2011