A bad application of STD?

Dec 14th, 2012

J. Thorburn

A bad application of STD?

One of Evan Edinger’s latest publications is an article in Oceanography, the scientific magazine of The Oceanography Society. His paper, entitled “Gold mining and submarine tailings disposal: Review and case study”, discusses the environmental impacts associated with submarine tailing disposal (STD) of gold mine wastes and describes a case study on a gold mine in Indonesia that Evan examined between 2002 and 2008.

This paper is part of a series of papers in Oceanography on STD (also known as deep-submarine tailings placement, DSTP). This series was inspired by a court case in Papua New Guinea, in which the villagers (who were also the local landowners) were trying to stop a Chinese mining company from dumping nickel mine tailings into a bay, and asked scientific experts, including Evan, to testify on their behalf.  

STD is the process of dumping mine tailings in the ocean, usually at depths greater than 100 m, rather than putting mine wastes into a constructed tailings pond on land. The mining industry promotes STD for handling mine tailings in seismically active areas, or regions with very high rainfall, on the argument that STD avoids the risk of tailings dam failure, and the possible contamination of rivers or surface ocean waters where most fishing takes place.  STD is also considerably less expensive than conventional mine waste management in a constructed tailings pond. 

Similarly, in Newfoundland, Vale-Inco plans to put nickel ore processing wastes into Sandy Pond, a shallow lake near its Long Harbour ore processing facility, rather than building a tailings impoundment.  This controversial decision has met with considerable opposition within Newfoundland. (The Sandy Pond Alliance is challenging the legality of the Fisheries and Oceans Canada provision under which Vale is allowed to put mine wastes into a natural water body.  The case will go to the Supreme Court of Newfoundland and Labrador in late February.)

As the series of articles in Oceanography points out, STD is not without risks of its own.  In the case study in Evan’s article, up to 30% of the tailings dispersed away from their intended dumpsite, reaching nearby coral reefs.  Furthermore, the ore processing in this mine rendered arsenic in the mine tailings unstable, with the potential to contaminate fish, including species consumed by local villagers.  Other articles in the series deal with toxicology of gold mine wastes tailings dispersal and metal dispersion, risk assessment and ecotoxicology, and turbidity and its biological impacts on corals. For more information, you can visit the article information page on the Oceanography website, or read the abstract


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