Experimental seabed mining will involve open cut strip mining of the sea floor. This raises many serious environmental concerns: 

• Habitat destruction from the excavation of the ore and the plumes of mud it will create causing loss of habitat, loss of endemic or rare species, reduced species diversity, loss of knowledge and future opportunities.
• The hydrothermal vents that will be mined are one of the rarest and most unique ecosystems known to science and are only just beginning to be explored and understood. Each vent site and its ecosystem is unique.
• Impacts of light and especially noise from undersea vehicles and mining on deep sea dwelling creatures and whales, dolphins, etc
• Disposal on the sea floor of 'subeconomic rock and sediment' (estimated at 250,000 tonnes)
• Disposal of waste from surface vessels
• The integrity of pipelines and possible leakage
• Toxic wastes from the processing of the ore
• Cumulative impacts of mining many sites over a relatively short period of time
• Pollution from surface ships and the risks of collision or spillage
• Existing studies for Solwara 1 and the approved Environmental Impact Statement do NOT include storage of the ore on land, transportation to a processing facility, processing, waste disposal or on-shipping.

Although advocates claim seabed mining could have certain advantages over land based mining, with a smaller area mined due to high grade deposits, less overburden to be removed, less waste and minimal infrastructure, the mining is not being done instead of land-based mining, it is additional AND none of these claimed advantages address the very serious environmental concerns.