Green Economy in a Blue World-Full Report

Mining massive sulphides, an example from the planned Solwara 1 deposit

In order to characterize the environmental and opportunity costs of deep-sea mining, it is helpful to outline the steps involved in the extraction and recovery of minerals from a seafloor massive-sulphide deposit. When mining begins at Solwara 1, in Papua New Guinea, indications are that extraction will be undertaken with mining machinery remotely operated from a vessel anchored above the mining site. Surface sediments will be scraped and removed from the deposit. The deposit will be cut by a bulk-mining machine and reduced to a particle size which can be pumped as a slurry through a riser and lift system (a pipe) to a surface production-support vessel. The slurry

will then be dewatered on the vessel, and the water filtered and returned for discharge near the seafloor. Dewatered ore will be transported by barge to an unloading and storage facility on land. It will then be transported by truck to a concentrating facility, where it could be partially processed into concentrated copper and zinc ore. Because Papua New Guinea, like most countries in the region, does not have an industrial-scale smelting facility, the concentrate would be trucked again to a port and shipped to an overseas smelter or shipped there directly. Only the initial mining, lifting, dewatering, and shipping of the ore would be novel mining industry activities in Papua New Guinea.

in a Blue World

Seafloor Mining

Rise/Lifting

Mining Support Vessel

Mechanical aspects of seafloor mining could result in damage to poorly understood species and habitats.

The Risers and Lifters could allow chemicals, sediments, or metals to leak from the pipes into the ocean

Mining support activities could result in dumping of mine tailings or waste.

Environmental Costs

Seafloor Mining could damage future scientific, medicinal, or recreational opportunities in the unique vent ecosystems.

Accidental contamination could affect seafood safety and production

Mining support vessel activity could displace local fishing.

Opportunity Costs

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