The International Maritime Organization (IMO) in a new study presented a number of recommendations to manage marine pollution from mining operations, calling for more research to better understand environmental impacts.
The Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP) produced the report “The Impact of Mine Tailings in the Marine Environment” from the findings of an international workshop held in Lima, Peru in 2015, noting that marine pollution from mining operations was “a growing concern.”
The report made number of recommendations for future mining work, but noted that there are major gaps that need to be addressed in the scientific understanding of the behavior of mine tailings in the sea at depths between 20 meters and 80 meters, and consequently the short- and long-term impacts on the marine environment and other potential users of marine resources.
“Scientific gaps in measurement and monitoring techniques in assessing impacts of existing and proposed new deep-sea discharges of mine tailings need to be addressed,” the report said.
Following the workshop in Lima, GESAMP established a dedicated working group to assess the environmental impacts of wastes from mining operations which have been disposed into the marine environment, under the co-lead of IMO and UN Environment, it explained.
A number of large-scale mines worldwide use marine or riverine disposal for mine tailings, in most cases under government permit, the report said.
The recommendations made by the report of what the researchers consider the “best practical waste management options” include discharging mine waste in deep waters (greater than 80 meters depth); mandating more on-land storage, such as tailing ponds; treatment of waste before discharge; and recycling or reusing mine wastes.
The report also made a number of recommendations to improve selection of waste discharge areas, including conducting baseline surveys of proposed disposal sites; avoiding areas where there is upwelling, to prevent subsurface tailings plumes and resuspension of deposited tailings; selecting low productivity environments, that are not used for fishing or are sensitive ecosystems; improving monitoring of water quality at the surface and at depth in disposal areas; and developing adaptive management and mitigation procedures.
The IMO is the Secretariat for The Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP), which is an advisory body, established in 1969, that advises the United Nations (UN) system on the scientific aspects of marine environmental protection.