Robot doesn’t destroy seabed habitat

A foreign company has proposed to bring in a robot to harvest the seabed, write Tailia Mika.

The Impossible Metals Company in North America is exploring opportunities on how to bring a seabed harvesting machine or robot to the Cook Islands, to be tested on how to mine without destroying the habitat.

These autonomous underwater vehicles (AUVs) are designed to minimize - environmental impacts, which is a different approach from the traditional approach that currently everyone else is using –the dredging tractor and riser system.

Chief Executive Officer (CEO) and co-founder of IMC, Oliver Gunasekara, who was amongst hundreds of experts who were in Rarotonga for the 52nd Underwater Minerals Conference recently with the goal of helping Cook Islands gain more knowledge about seabed mining, said he approached the government about the idea of bringing this technology to the Cook Islands.

“We have (approached the government about bringing the machine to Rarotonga), and they've suggested that we need to work with the three license holders so we have had some preliminary discussions, and I'm hopeful we'll be able to conclude something,” he told Cook Islands News.

“It's also quite expensive, as all of our development is in North America, so it's quite a long way to bring this vehicle here.

“Our technology is completely different to the traditional approach which is really a dredging tractor and riser pump system, with a production support vessel, and then a ship-to-ship transfer to a cargo ship that moves the nodules to shore.

“We read about people protesting because they  are not happy with this approach.I actually went and joined the protest and I think it's good that you have an open society where people can protest and so I wanted to learn and listen. I learned  everyone is concerned about the environmental side of things.”

In creating this environmentally-friendly machine, Impossible Metals took the problem and broke it into first principles and three main areas.

The first was the physical collection on the seabed, how to physically pick up the module; second was how to transport the modules from the deep seabed, typically around five kilometers deep, to the ship; and the third problem was how to get them from the ship to shore for processing.

Some of the ideas around the vertical transport of the nodules was to use a lift bag where they had compressed air and they could effectively go up like a balloon in the ocean.

“Of course we considered a traditional riser system such as a skip lift, also a mechanical lift and a chair lift type system. We considered a drop weight, we considered using a winch off the side of the boat, we considered the traditional pumping riser system that everyone else is using and we ultimately considered what about if we put these inside the robot, which is what we chose,” Gunasekara explained.

The robot is battery powered, it does not have any tether, rope or line to the support, and dives down once it's placed into the water to just about two meters above the seabed floor.

It does not land and it hovers with the help of a unique technology called a buoyancy engine which allows the vehicle to hover and also move up and down the water column.

Once the vehicle is hovering about two meters above the seabed floor, it uses cameras and lights to look at the seabed and it's looking ahead of the vehicle to find the nodules.

Not only does it look for the nodules, but it also looks for a megathorner, animal life that can be seen with a camera.

“Now, we can't see bacterial or very, very tiny life, but typically, any life that's one millimeter or larger, we can see like a coral or a sponge or other forms of megathorner,” Gunasekara said.

“If the camera system detects life, we leave a quarantine area around it. And if we don't detect life, the camera directs an array of arms, these are robotic arms that hang from the vehicle and what they do is they move to the nodule and they operate a claw, pick up the nodule, and then they place it inside the vehicle.

“So it's a mechanical system whereby we're picking and placing inside the vehicle. We have a conveyor system, it’s a little plate and then once they're placed on the plate, they get moved up into the hopper, the storage of the vehicle.

“And we have an array of these arms, so we can move quite quickly. And the vehicle is moving constantly, once it has filled its payload, and we typically leave behind about 30 percent so maybe 1% has megathorner, but then another 29%, we just want to preserve for biodiversity purposes.

“The Biodiversity Convention recommends 30% is a good number to leave behind. But once the payload is full, we use that buoyancy engine and the battery to make the vehicle lighter by pumping water out, and the vehicle floats to the surface. Once it's on the surface, we have an automated craft.”

Meanwhile, the CEO acknowledged the Cook Islands government and the seabed minerals authority on a great job of the precautionary approach, getting the science right.

He is of the view that the technology used will have a huge impact because they are hovering, there's no sediment bloom because they don't touch the seabed floor but the nodules.

He explained that there's a little bit of disturbance when they pick up the nodule but there's no tracks, no riser system, no pumping the sediment so no major sediment blooms.

They also have much less noise and most of the noise comes from the differential positioning whereas with the riser system, the ships have to stay very still because they have a big tube going down to the crawler.

According to Gunasekara, that needs thruster, a technology called differential positioning that keeps the boat really still.

”Unfortunately it makes massive amounts of noise and most of that noise is at the top of the water where most of the dolphins, the whales, the big ones live that are affected, we don't need that,” he added.

“I think if we remove all of the nodules in one area, we're going to destroy biodiversity and the effect of the dredging is that it removes the top five centimeters and that's where there is a lot of life, a lot of bacteria that has very special properties.

“We know from some of the scientific data that you don't have to go very many kilometers away, and you have completely different species.”

He explained that their approach of selective harvesting has two major benefits, one is they preserve 30% or so, a programmable number, of the hard substrate as species like octopus lay their eggs there and if everything is removed, they'll be wiped out.

The second thing is the biodiversity, the megafauna, but also the tiny fauna, the bacteria, if you remove everything, it's all gone, Gunasekara emphasised.

As for the cost, he explained that they’re between a third and a half the cost for the same rate of production and the reason why they’re a lot less expensive is because they don't need that dedicated production support ship, nor a ship-to-ship transfer.

One of the challenges with ship-to-ship transfer is that no one has yet proven how well it will work, Gunasekara stressed.

He added that one of the big problems with the traditional approach is that it's all single point of failure. If the collector fails, it will probably take weeks to recover it, fix it, and get it redeployed same with the riser system, and the ship-to-ship transfer.

Meanwhile, this architecture was invented in the 1960s and in the 1970s, there was actual testing done. The company was later formed four years ago, and this group of relatives felt there should be a better way.

The CEO emphasised that this new technology can bridge the gap between those that are still on the fence or opposed.

“We would welcome the opportunity to try to bring the test vehicle that we've already tested off Florida at two kilometers depth, to bring it next year here to the Cook Islands, to show it to the people and let people see how this operates and how it has far less of an impact,” he said.

Written by Talaia Mika | Published in Environment, National