Our mining operations produce mineral wastes and a comparatively small amount of non-mineral wastes. While efforts are made to minimize non-mineral wastes through reuse and recycling, mineral wastes, tailings and waste rock are an unavoidable result of the mining process.
Upon exposure to air, the newly exposed surfaces of mineral wastes begin to weather and oxidize. Because oxidation products can have water quality impacts, Kinross requires our mines to understand these geochemical transformations and to design and operate the mine to avoid or minimize impacts. Mineral waste management plans are routinely reviewed and updated to ensure that facilities are both physically and chemically stable. Regular monitoring and inspection are required to verify that design expectations are being met.
We continue to support and participate in the International Network for Acid Prevention (INAP), an industry group founded in 1998 that supports the development of technical guidance and standards for the prevention and control of acid mine drainage. In the interest of acid drainage prevention and control, INAP’s research and guidance documents are available to everyone through its website: www.inap.com.au
Tailings are disposed of in storage facilities designed, built, operated and closed to meet regulatory and engineering safety and environmental standards. Our tailings management standard was strengthened in 2010. Management programs are in place at each of our sites to assess the management and stability of tailings and heap leach facilities. They include a detailed water balance accounting to assure sufficient storage capacity and a review of operational procedures. At mine closure, tailings dams are decommissioned and reclaimed to increase their long-term stability and ensure that they become a part of the post-mine land use.
In addition to requiring an annual inspection of each Kinross tailings facility by a geotechnical engineer, we apply an additional level of oversight led by an external geotechnical expert who reports to senior management at Kinross. We completed third-party technical reviews of tailings storage facilities at Kettle River-Buckhorn, Round Mountain, Paracatu, and Crixás in 2010 and at Paracatu, Kupol and Fort Knox in 2011.
At the end of 2011, Kinross received its operating permit for the new Eustaquio tailings storage facility at Paracatu. Tailings began to be placed in this facility in March 2012.
The Kupol tailings facility began operation in 2008. The facility design includes, below the dam, a sump to capture any runoff from the dam face or seepage beneath the dam. In late 2010, monitoring detected seepage below the dam, which was captured in the sump and returned to the dam. While there was no impact to environmental receptors, a small amount of seepage escaped the sump for a short period and was detected in the creek downstream. Immediate improvements in pumping and containment capacity to ensure that seepage was captured and returned to the dam. Kinross initiated investigations and determined that the seepage had no impact on the stability of the tailings structure or on downstream water quality. To decrease the seepage rate, tailings disposal procedures were modified to improve beach development on the dam and side abutments. Seepage has continued to decrease and is safely captured and pumped back to the tailings facility. Kupol reported this incident to appropriate regulatory authorities and has continued to keep them apprised of the situation. No regulatory action has been taken by the authorities.
Soon after our acquisition of Red Back Mining Inc. in 2010, seepage was detected adjacent to the tailings storage facility at Tasiast. After determining that the facility was unlikely to perform as originally designed, we accelerated designs, permits and the construction schedule for a new tailings facility to replace the existing facility. Meanwhile, we made operating and design changes to minimize, capture, and return leakage to the process plant. The new tailings facility is currently under construction and is scheduled to replace the existing facility in late 2012. Given that there is no recoverable or usable groundwater in the area, there has been little environmental impact. Nevertheless, a number of monitoring and abstraction wells have been installed around the facility to recover seepage this year. Kinross has kept the Mauritanian regulatory authorities apprised of the situation since we first recognized the problem, and they appear to be satisfied with Kinross’ efforts to correct the situation.
Non-mineral wastes include everything that doesn’t originate in the actual mine, such as spent batteries, fluorescent light bulbs, cupels and crucibles used in the refining process, waste oil and spent solvents. Grinding media (mill liners), truck tires, and reagent packaging also fall in this category. We are continuously seeking ways to reduce waste generation as well as increase the amount of waste we can recycle or reuse. We dispose of materials that cannot be recycled or reused in a manner that is environmentally acceptable, in compliance with regulations and using handling and storage procedures that ensure people and the environment are protected. We have recycling programs at each of our operations. For example, Kupol shreds plastic containers for resale within Russia. In 2011, we recycled approximately 47% of non-mineral wastes.