2024-04-02_REVISION - M1977493 - Laserfiche WebLink

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Permit M-1977-493—Climax Mine Technical Revision 37 (TR-37) lessons learned. Climax will continue to develop and implement innovative reclamation technologies to improve reclamation success. To date, Climax has placed nearly 1,300 acres into its reclamation programs. Projects have included capping and revegetating existing dam faces, capping and revegetating TSFs, demolition of obsolete buildings and facilities, revegetating existing OSFs, reclaiming historic mine sites on the property, and developing freshwater facilities from a reclaimed TSF and a reclaimed gravel pit. Several of these innovative and highly successful reclamation projects are described in detail below. E-3.1 Eagle Park Reservoir Climax's Eagle Park Reservoir was historically a molybdenum oxide TSF. In 1996 and 1997, approximately 1.3 million tons of molybdenum oxide tailings were removed from the TSF and the site was reclaimed as a freshwater storage facility. The Eagle Park Reservoir now provides water storage for water users downstream in the Eagle River Basin. The stored water in the reclaimed reservoir meets or exceeds stream standards, and the revegetation on the banks equals or exceeds the vegetative cover and vigor of nearby native communities. This project earned Climax the DRMS's 1998 Hardrock Reclamation Award. E-3.2 Robinson Tailings Storage Facility Reclamation Capping began on Robinson TSF in the 1980s with direct hauled overburden from the open pit mining operation. Prior to 2005, approximately 300 acres of the TSF surface were drained and capped starting on the drier south and west edges. In 2005, Climax received DRMS approval (TR-13) for a combined wet and dry cap on the TSF and began construction to complete the project. An additional 102 acres of dry cap were placed. Geogrid was used to stabilize the wettest areas. Previous reclamation efforts have used biosolids to supplement available growth media. Although the use of biosolids has successfully enhanced revegetation, Climax will no longer be using biosolids due to concerns with potential per- and polyfluoroalkyl substance (PFAS) in the sources. In addition to capping, the majority of Robinson TSF has been revegetated and 114 acres have achieved bond release. E-3.3 Storke Area Reclamation The Storke Yard historically included many underground mining and support facilities as well as the mine's aggregate resource. Additionally, the Arkansas River headwaters flow across Climax property through the Storke Yard. In the early 1970s, a section of the river was diverted through a buried 2,000-foot-long concrete pipe. Starting in 1989, the gravel pit was reclaimed to a freshwater pond and the surrounding area was revegetated. The Arkansas Pond now supports a sustaining trout population, and the surrounding vegetation community is well established and diverse. In 1994, the equipment from Storke Yard and most of the buildings were demolished in preparation for the reclamation of the area. Much of the area was graded and revegetated in 1995 and trees were planted into the reclamation. This area now supports a diverse grassland vegetation community. Climax's most recent project in the Storke Yard was a project to daylight the Arkansas River into a newly constructed channel. The new design incorporated a stable meandering channel and floodplain that mimics the conditions up and downstream. The channel was designed to pass a 100-year, 24-hour event, and revegetation along the channel includes transplants of native vegetation, willow and birch shrubs, and Engelmann spruce trees harvested on site. The site demonstrates sustaining vegetation establishment and hydrologic stability after numerous years of vary flow rates. Reclaimed portions of the overall Storke Area have since been successfully reclaimed and the bond released. No further actions or cost are anticipated for these specific reclaimed areas. E-3.4 Dam Faces To date, Climax has stabilized and capped all or parts of the faces of 1 Dam, 2 Dam, 3 Dam, 5 Dam, and Robinson Dam. Robinson Dam and 4 Dam were designed for rock cover only and a permanent vegetation cover Exhibit E E-2 March 2024