January 14, 2016      

Treasure at 500 fathoms

Davy Jones’ locker is getting some visitors in mid-2016: subsea mining robots. Using robots as subsea miners is a first. These autonomous, deep-sea machines will drop down three-thousand feet beneath the surface of the Bismarck Sea some 18 miles off the shore of Papua New Guinea to a mining site called Solwara 1.

A treasure in copper, gold, zinc, and silver await in the cold, dark abyss. Perfect job placement for a robot.

Behind the venture is Nautilus Minerals, a Toronto-based mining company that has an agreement with the government of Papua New Guinea to coastal subsea mineral rights. Nautilus is jointly owned by Barrick Gold Corporation, Anglo-American, Teck Cominco, and Epion Holdings.

Papua New Guinea has a legal right to acquire up to 30 percent equity in the project. Nautilus currently holds 51 exploration licenses in the Bismarck/Solomon Seas in the southwest Pacific, covering 42,000 square miles, which is slightly larger than the state of Ohio (see map).

The Solwara 1 is a large Seafloor Massive Sulfide (SMS) deposit; the major investment feature of SMS deposits is their high content of copper, gold, zinc and silver. SMS deposits are considered by geologists to be the modern equivalents of ancient massive sulfide deposits that have been, and continue to be, mined on land today.

We’ve been following the Nautilus Solwara project for more than two years now, and finally it looks as though the time is at hand to do a little deep-sea digging. See our 2014 and 2015 reports here:

See related: Deep Sea Dive for Rare Earth Elements

See related: Giant Subsea Robots Mine for Ocean Riches

See related: Robotics in Oil, Gas & Mining: 2015-2020

nautilus dig

Really big tools

As a floating operations center, Nautilus will use a 740-foot production vessel (see photo above) that is currently under construction in China and will be ready for duty in early 2018.

The ship is also home to deep-diving, mining robots that will be lowered 3000 feet down to the seabed in order to crunch up the Seafloor Massive Sulfide (SMS) deposits and send them topside to the production ship.

The deep-sea mining robots were built by UK-based Soil Machine Dynamics, which generally builds machinery for offshore oil platforms, undersea cable operations and heavy-duty deep-sea jobs.

The main Solwara robots are a pair of mega-size excavators (see photos). One uses counter-rotating heads that are 13 feet wide and studded with tungsten carbide picks, ?designed to chew through the metal-rich chimneys that form around superhot, water-spewing, sulfurous vents in the sea floor. Its partner uses a studded drum that is 8 feet in diameter and 13 feet wide to pulverize rock walls,” reports Eureka Magazine.

“Dredge pumps built into these machines will push the ore back to a central pile on the sea floor, 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.”

Toe dipping mid-2016

Before any deep dives the robo-miners need to be tested, and that will be done closer to shore in shallow water. Those tests will take place mid-2016, which will then be followed by deep-sea trials prior to the arrival of the production vessel. Mining will begin in earnest at Solwara 1 near New Ireland province in 2018.

In the frigid, dark depths of Solwara 1, the robo-miners are scheduled to spend 30 months digging out 2.5 million metric tons of ore containing $1.5 billion in high-value metals.

The actual mining process is in four steps:

  1. The first excavator’s 13-foot rotating drum with tungsten teeth will chew into and break apart the smokestacks of SMS on the sea floor.
  2. The second excavator then uses its 8-foot diameter to pulverizes the rock.
  3. Dredge pumps built into these machines will then push the SMS ore back to form a central pile.
  4. Finally, a third robot then feeds the slurry of crushed rock and water up a pipe to the production vessel. Once on board the water will be separated off from the slurry before being shipped off to China for processing.

Ecosystems in jeopardy

Although the mining machines will be operated so as to minimize any extensive damage to the ecosystems, the mining process will not be damage free. Mining is by definition a destructive process of ore extraction.

Marine biologists protest 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,” reports Eureka Magazine.

It’s a warning that Nautilus says “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.”