2017-06-05_REVISION - M1977300 - Laserfiche WebLink

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Technical Revision 25, Rev. 1 Schwartzwalder Mine outfall (DIS-001A), has generally complied with monthly discharge limits for the past eight months. Rejected water, also known as concentrate, is redirected to the mine pool. The two process streams are physically separated by the treatment membrane and are never allowed to comingle once processed. Although the treatment system effluent may, on occasion, not meet a monthly discharge limit for a - particular parameter, the water is still treated and, therefore, not toxic. The chemical characteristics of the treated water, as presented on numerous discharge monitoring reports (DMRs), does not have the chemical signature of"acid and toxic producing materials", "acid mine drainage", or"designated chemicals", as defined in the rules for Hard Rock, Metal, and Designated Mining Operations. Furthermore, the mesa on which the NWTP is constructed, contains a berm that will prevent the contents of the clean water tank from entering surface water directly. The NWTP is also equipped with integrated control computers that monitor key process parameters and have several safety features that will deactivate all operations and physically eliminate the possibility of untreated water flowing into the clean water tank. The system is operated on both an automated and a manual basis with capabilities for the operator to monitor conditions remotely. All process parameters are interlocked through programmable logic control (PLC) digital computers that have the ability to ultimately deactivate the system in accordance with emergency conditions. RO emergency deactivation is the default response in any adverse scenario and again will utilize control valves that eliminate the flow of any unprocessed water on a mechanical level. Restarting the RO system will always require a physical presence. 3.1.3 Ion Exchange Columns Cotter will install three of the four IX columns from the OWTP into the NWTP. The fourth IX column will be stored on site, in reserve. These columns will be primarily plumbed to treat RO effluent prior to discharge. These columns are necessary to polish the RO effluent to allow Cotter to meet the uranium -- discharge standard specified in its Colorado Discharge Permit CO-0001244. 3.1.4 Reactor Tank During the alluvial material excavation project and decommissioning of RML #2, the current concrete containment will be demolished and placed into the Minnesota Adit. Currently, the concrete containment collects effluent from all the sumps and creek pumps. Once this structure is gone Cotter must install a new tank to collect sump and creek water. Cotter intends to utilize an existing, 17,000-gallon tank located on the mesa near the NWTP, that is not currently in service. This tank will serve as a reactor tank that collects sump and creek water into which flocculant and sodium hydroxide will be injected. The flocculant will precipitate solids, and the sodium hydroxide will raise the pH, both of which will allow cleaner water to enter the clarifier inside the NWTP. The proposed reactor tank is 12 ft in diameter and will be located outside the Steve Adit. The reactor tank, along with the 15,000-gallon backfill slurry tank, will be located within a lined secondary containment - berm that will be constructed with a minimum capacity of 36,000 gallons. This capacity is 110% of the entire contents of all tanks within the secondary containment area (see Figure 3-2). Note that the molasses or carbon tank will not be included within this secondary containment. Cotter will use smooth, Mine Permit M-1977-300 Cotter Corporation(N.S.L.) 13 June 2017