​Underwater mining more sustainable than land mining

A new report has shown that subsea copper mining is more sustainable than terrestrial mining.

The Earth Economics report, which carried out independent environmental and social benchmarking analysis based on natural capital accounting, found that Nautilus Minerals Solwara 1 “has the potential to significantly reduce social and environmental impacts commonly associated with large surface terrestrial copper mines”.

“Mining in the deep seabed (assuming the creation of sufficient biodiversity conservation sites) has fewer identified, quantified and monetized impacts than terrestrial mining.

“Producing one tonne of copper results in far less freshwater use, mineral waste, energy use, area of disturbance, and CO2 emissions in Solwara compared with terrestrial mines,” the report stated.

The study compared the Solwara 1 operation, the Prominent Hill mine, Bingham Canyon, and the proposed Intag mine.

It explained that the “deep seabed at the Solwara 1 mine is an advantageous choice of mining site for a number of reasons [as] no people live at the proposed mine site, and there are no cultural or historical claims to the site; The mine site itself is quite small, covering only 14 hectares of seabed; natural resources are less impacted by operations at this site as surface or groundwater freshwater resources will be not used or contaminated at Solwara 1”.

“In addition, there is limited overburden covering mineralised material, resulting in very little waste rock material; finally, the proposed mine operation wastes will be dwarfed in comparison to the impacts of a nearby erupting underwater volcano.

“Even excluding these by-product credits, the mineralisation copper grade alone is approximately 7 per cent, a remarkably high percentage which will lead to numerous efficiencies.”

Nautilus added that “monetary damages (measured in terms of USD/year) resulting from terrestrial mines is estimated to be significantly more than that of the proposed Solwara 1 project (4 to 13 times per tonne of copper produced for the three mines used in the comparison)”.

Mike Johnston, Nautilus' CEO, explained that growing copper demand requires the resources industry to look at more sustainable ways to meet this demand.

“As showcased in Earth Economics' Report, seafloor mining has the potential to not only provide economic benefits within the communities nearest to the operations while minimising the impact of copper mining, it also has the potential to change the physical nature of the mining industry for the better."

"We believe that the proposed Solwara 1 project will launch a new frontier in the blue economy and resource sector,” he added.

Underwater mining has been moving ahead globally, with the International Seabed Authority this time last year issuing several seabed mining licences.

Three plans of work were approved for the exploration of polymetallic nodules for United Kingdom Seabed Resources, Ocean Mineral Singapore, and the Cook Islands Investment Corporation.

The Government of India, the Germany Federal Institute for Geosciences and Natural Resources, as well as the Russian Ministry of Natural Resources and Brazil's Companhia de Pesquisa de Recursos Minerias had applications approved as well.

It came after the United Nations published its first plan for deep sea mining.

In late March new underwater mining robot development programs were launched in Europe.

Under the European Union’s Horizon 2020 program a three and a half year, 12.6 million Euro R&D project is examining robotic underwater mining systems.

Dubbed ¡VAMOS! (Viable Alternative Mine Operating System), the project is focused in designing and building a robotic underwater mining prototype as well as associated launch and recovery equipment.

To read an infographic outlining the pros and cons of deep sea mining, click here.


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