Nautilus’s machines have been ready to go since 2012, when a dispute between the firm and the Papua New Guinean government stalled the project. What broke the impasse was the company’s offer to provide Papua New Guinea with intellectual property from the mining project.
The deal enabled Nautilus to get financing to build a €127million ship, the first of its kind, which will deploy the subsea mining robots and process the ore they recover. This 227m-long production vessel is being built in China and is scheduled to depart for Papua New Guinea in early 2018.
The mining robots have been built by Soil Machine Dynamics, based in the UK, which supplies construction equipment for laying undersea cables, servicing offshore oil platforms, and other heavy-duty deep-sea jobs. The main robots are a pair of articulated-lorry-sized excavators. One uses 4m-wide counter-rotating heads studded with tungsten carbide picks, designed to chew through the metal-rich chimneys that form around superhot water spewing from sulphurous vents in the seafloor. Its partner uses a studded drum that is 2.5m in diameter and 4m wide to pulverise rock walls.
Dredge pumps built into these machines will push the ore back to a central pile on the seafloor, where a third robot will feed the slurry of crushed rock and water up a pipe dangling from the production vessel. There the water will be separated from the ore, which will be loaded onto another ship and carried to China for processing.
Nautilus is still negotiating for access to a shallow-water site for an initial subsea test of these machines, which it hopes to begin in mid-2016. If time allows, the machines will also get a deep-sea trial before they are integrated with the production vessel. Barring that, they will have to prove their mettle at Nautilus’s first mining site, Solwara 1, 30km from shore in Papua New Guinea’s New Ireland province.
The robotic diggers are planned to spend 30 months scouring the Solwara 1 site, bringing up 2.5million metric tons of ore containing metals worth more than US$1.5billion at today’s prices. Next, the robots will likely set to work on one of Nautilus’s 18 other prospects in the Bismarck Sea or one of its 19 discoveries off the shores of the Polynesian archipelago of Tonga.
But some marine biologists warn that deep-sea mining interests are outpacing the readiness of scientists and governments to assess and manage the environmental impact, saying that robo-miners will strip away deep-sea ecosystems that are as unique as they are poorly understood.
Nautilus says it is taking pains to study these ecosystems and will protect them to the extent possible. A refuge zone within the leased area, for example, will provide a source of local fauna for recolonisation of the company’s deep-sea strip mine.
Nautilus’s CEO, Michael Johnston said that, with luck, the mining will prove no more devastating to these vent communities over the long term than the frequent earthquakes and outpourings of lava that these deep-sea creatures are somehow able to survive.