A/HRC/21/48 C. Waste management practices in extractive industries 10. The greatest volume of waste generated by mining activity is waste rock, which is often reactive. Overburden is also a significant waste, particularly with surface mining techniques. Wastes may be disposed of in surface heaps or underground. Other wastes include drilling mud, cuttings and water used during excavation, which may be directed into lined or unlined pits. The principal waste generated by beneficiation is the solid, liquid and/or gaseous residue left over after the process of separating the desired resource from the undesired fraction. These residues are commonly referred to as tailings, but also known as mine dumps, slimes, tails, refuse, leach residue or slickens. Each resource extracted through mining techniques will have its own tailings composition, which varies depending on the location and purity of the desired resource. 11. There are many techniques for the waste management of tailings and red muds. Despite well-documented environmental impacts, disposal in oceans (submarine tailing disposal or STD), rivers or streams (riverine tailing disposal or RTD) is still considered an option by some countries.7 In 2003, the World Bank reported that the practice of RTD was being phased out due to the well-documented negative consequences on surrounding environments, and that STD was the waste-disposal procedure “preferred by many mining companies planning large-scale operations in mountainous areas of active seismicity, particularly in Southeast Asia and the Pacific.” 8 12. Ponds are used to dispose of process water or other solutions that are unsuitable for discharge or inappropriate for addition to tailings impoundment. Settling ponds are employed at in situ mining operations to remove radium and/or other toxic substances from solution prior to discharge. Deep disposal wells are sometimes used to dispose of wastes that cannot be recycled, treated or discharged (e.g. brines, laboratory wastes, etc.). Another form of disposal is the mixture of a certain quantity of tailings with excavation waste and cement, creating a product that can be used to backfill underground voids. The previous mandate holder examined the practice of dismantling ships laden with hazardous material in his thematic report on shipbreaking (A/HRC/12/26). 13. Land application areas are also used to eliminate water generated in the bleed solution during extraction, particularly in solution mining. Beneficiation wastes generated by solution operations of uranium mining may also be shipped to waste disposal facilities. Phytostabilization uses plants for long-term stabilization and containment of tailings, by sequestering pollutants in soil near the roots, which may reduce the bio-availability of pollutants and exposure by livestock, wildlife and humans. When leaks or spills occur in the marine environment, chemical dispersants may be used to help mitigate the impact of oil spills. In the case of the Deepwater Horizon oil spill in the Gulf of Mexico, over 650,000 gallons of dispersant were applied at the surface and underwater. These chemical dispersants, however, may not degrade as intended and warrant consideration as a waste of oil and gas extraction. For example, research has shown that dioctyl sodium sulfosuccinate (DOSS), a component of a dispersant recently used to assist in the remediation of the Deepwater Horizon oil spill, was present as a large plume 200 miles from the wellhead five 7 8 OECD Global Forum on Environment, “Focusing on Sustainable Materials Management,” Materials Case Study 2: Aluminum (2010), p. 17; see also Freeport-McMoRan Copper & Gold Inc., Controlled Riverine Tailings Management at PT Freeport Indonesia (Papua, 2009). World Bank Group and Extractive Industries, Extractive Industries Review, Striking a Better Balance, The Final Report of the Extractive Industries Review, vol. I (December 2003), p. 31 (acccording to the report, in 2003, only three mines in the world, all on the island of New Guinea, still used riverine tailing to dispose of mine wastes). 5