2005-08-05_REVISION - M1977493 - Laserfiche WebLink

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Pond flows to the base of 5-Dam where sulfuric acid is added to reduce pH to approximately 8 prior to discharge. This system, as configured, provides only partial two-stage treatment of the impacted waters at the site. However, the existing system effectively treats all of the impacted flows to meet CDPES effluent limitations. Proposed Water Treatment Rationale and Plan The Climax Water Treatment Upgrades, also referred to as the Climax Sludge Management Project, is a $79 MM project designed to assure short and long-term compliance with existing CPDES discharge limitations. The project represents the culmination of a four-year alternatives analysis study, and represents the most technically supported approach for reducing sludge deposition/filling in the Tenmile and Mayflower Tailing Impoundments. The upgrades will also assure compliance with current and projected effluent limitations associated with the Climax Mine CPDES Permit and provide for improved discharge water quality. Once this project is completed, it is expected that the upgrades will serve water treatment system requirements for a period in excess of 20 years. The principle driver for modification of the Climax Water Treatment System is limited low density water treatment sludge settling capacity in Mayflower and Tenmile Tailing Ponds. Significant volumes of solids generated by water treatment activities over the past twenty years have been deposited in the ponds, reducing settling area and storage volume in Mayflower Tailing Pond. A secondary driver exists with the new statewide standard for aluminum. Climax identified water management changes and treatment alternatives that would address the shrinking settling capacity in Mayflower Pond and the potential aluminum limitation and concluded that the existing pond treatment system requires near term modification to maintain sufficient residence time for metals precipitation in the treatment ponds. Moreover, improvements are needed to the two stage pH adjustment currently used to treat water at Climax in order to effectively remove aluminum. Figure 1 shows the general layout of the proposed upgrades. The strategy for addressing water treatment needs calls for collection and mixing of key impacted flows in a collection chamber near the existing Lime Station, and treatment of these combined flows in a Sludge Densification Plant (SDP). Treated water from the SDP will be routed through Tenmile Pond to a new second stage neutralization mix pond at the base of No. 3 Dam, prior to entering Mayflower Pond. The SDP and Tenmile Pond will be considered first stage treatment, while the No. 3 Dam mix pond and Mayflower Pond will continue to be considered second stage treatment. Also included within the process design are necessary upgrades to the Lime Station and enhanced electronic process control at key site locations. The SDP will treat most of the flows throughout the year, and during high flow periods, excess flows will be neutralized and handled in the existing pond system. On average, 95.3% of the solids loading to first stage neutralization will be handled by the SDP. Upon implementation of the water treatment upgrades, sludge loading to Mayflower pond will be reduced from the current estimated 25.6 million pounds to 6.4 million pounds per year of dry solids. The densification plant will produce a 20%+ solids sludge that can be stored and disposed of in constructed cells on Tenmile tailing Pond. Two cells will be required to allow for alternative cell use and sludge densification to projected 50% solids. The Sludge Management Project is not in and of itself a water treatment system and therefore not singularly capable of meeting discharge permit limits. The upgrades are intended to complement and fortify the existing water treatment system at the Climax Mine. An addendum to the Climax Mine Reclamation Permit, Exhibit G, Water Information is attached with feasibility level design considerations for the water treatment upgrades. Climax considers components of the constructed system to be Environmental Protection Facilities under the Climax Mine Environmental Protection Plan. Plans provided in Exhibit G are feasibility level designs and