SAMS news room

Scottish scientists unearth effects of mining waste disposal

Marine scientists from a Scottish institute who conducted the first study into the impacts of mine tailings disposal into the deep sea have been recognised by a prestigious scientific journal.

Researchers from the independent Scottish Association for Marine Science (SAMS), near Oban, and its commercial partner SAMS Research Services Ltd (SRSL) conducted surveys in Papua New Guinea into the effects of deep-sea tailings placement (DSTP) on seabed biological communities.

Their findings, which have been published by Nature’s online journal Scientific Reports, demonstrate significant and long-term impacts on the seabed ecosystem at depths down to 2,000 metres.

In November and December 2007 the team of scientists – Dr David Hughes, Dr Tracy Shimmield, Professor Kenneth Black and Dr John Howe – took seabed samples at various stations around the islands of Lihir and Misima, comparing untouched areas of the seabed with areas receiving discharges of finely-ground rock slurry from mines on the islands.

At the Lihir gold mine, which discharges 100,000 megalitres of tailings slurry every year – the equivalent of 40,000 Olympic-sized swimming pools – the numbers of worms, molluscs and other small, sediment-dwelling animals are drastically reduced in areas directly affected by tailings.  

At Misima, where DSTP took place for 15 years, ending in 2004, their results showed that the seabed community was recolonising the area affected by tailings but its composition was still very different three-and-a-half years after the end of tailings discharge.

Lead author Dr David Hughes said: "The waste material from these mines is made up of fine particles of rock and chemicals from the mineral extraction stage. The waste product is dense enough to fall onto the seabed but fine enough to be disturbed. No-one had looked at the effect of DSTP in the deep sea until now, but it’s in the interest of mining companies to know what effect their tailings have on the seabed. From a scientific point of view, we also need to understand how long it will take for the ecosystem to recover from this type of disturbance."

SRSL is an industry leader in DSTP and can advise mining companies on how best to dispose of mine tailings, reducing potential harm to the marine environment. 

Dr Tracy Shimmield, SRSL managing director, said: "With a worldwide demand for minerals there is a need for sustainable methods of mine waste management.

"DSTP is becoming an increasingly used practice and our research shows that there is an impact. However, by better understanding the environment in which the tailings may be placed, there is an opportunity to minimise any impact. 

"It is important that scientists, industry and governments work together to provide information to allow the best decisions to be made.

"This research shows we at SRSL have the expertise to conduct this work effectively and produce accurate data that has been recognised by the global science community."

The paper, entitled “Ecological impacts of large-scale disposal of mining waste in the deep sea”, is based on a project undertaken on behalf of the Department of Environment and Conservation of Papua New Guinea. As a result of the study, the government has, alongside SRSL, developed general guidelines for the use of DSTP in the country. SRSL has also created specific guidelines for the companies operating two of the mines in Papua New Guinea.

ENDS

 

For more information contact Euan Paterson, SAMS media and communications officer E: euan.paterson@sams.ac.uk   T: +44 (0)1631 559342 

 

Notes to editors

• SAMS Research Services Ltd (SRSL), founded in 2002, provides specialist marine consultancy and survey services, under pinned by cutting-edge science. More...
• The Scottish Association for Marine Science (SAMS) is Scotland’s largest and oldest independent marine science organisation and based near Oban, Scotland. SAMS is a charitable organisation (009206).
• In terms of DSTP, deep sea is defined as a depth of 1,000 metres or greater.