International Assessment of Marine and Riverine Disposal of Mine Tailings1

Abstract

This paper summarizes a report of a world-wide inventory of operating mines that dispose of mine tailings to marine and riverine waters and a review of what is known about the environmental impacts of those discharges. The report was commissioned by the International Maritime Organization, specifically the IMO Secretariat for the London Convention 1972 and the 1996 London Protocol (LC/LP), in collaboration with the United Nations Environment Programme (UNEP)-Global Programme of Action. These are the primary international instruments to protect the world’s oceans from pollution. The objectives of the LC/LP are to protect the marine environment from all sources of marine pollution, and, in particular, control and manage the dumping of wastes and other matter at sea (LC/LP 2003). Background Mining is essential to living as we know it. Mining is not an environmentally friendly activity. Extensive efforts have been made world-wide to minimize environmental damage from mining activities, but the job is not done. The biggest environmental challenge in mining is the management of mine tailings. Mine tailings are what is left over from the mined ore after the target mineral (e.g., copper or gold) has been separated from the ore. Separation is achieved by an industrial process using physical grinding and crushing to break the ore into small particles. For iron ore, this is followed by magnetic separation