A watertight designNautilus Minerals’ CEO Mike Johnston on deep-sea mining equipment
Nautilus Minerals’ CEO Mike Johnston on deep-sea mining equipment
By Elle Crosby
September 05, 2017
Nautilus Minerals, led by CEO Mike Johnston, is spearheading the world's first deep sea mining expedition slated to take place in early 2019. Courtesy of Nautilus Minerals
Nautilus Minerals is expected to begin harvesting high-grade minerals from the bottom of the ocean in early 2019, and CEO Mike Johnston has been in the front seat during the conception and development of the world’s first seafloor mining project. After twenty years as a geologist at mines on land, Johnston took on the position of vice-president for strategic development and exploration at Toronto-based Nautilus in 2006. Six years later, he was appointed interim CEO before being offered the permanent position in 2014. During his tenure at Nautilus, the company has been a trailblazer in the realm of deep sea mining. It delivered the world’s first NI 43-101 resource mine plan and environmental impact statement for mining seafloor massive sulfides (SMS) in its Solwara-1 project located at a depth of 1,600 metres in the national waters of Papua New Guinea (PNG). It also obtained the first exploration licence granted to a publicly listed company by the International Seabed Authority (ISA) and developed the first commercial exploration and resource evaluation programs for polymetallic nodules in the Clarion Clipperton Fracture Zone (CCZ) in the South Pacific Ocean.
Now the company is nearly ready to start digging at Solwara-1. To extract the minerals, Nautilus has created specially designed underwater mining tools adapted from those used in the offshore oil and gas and terrestrial mining industries. These machines will cut up the seafloor (similar to how a tractor tills soil) to a depth of five to ten metres to loosen the ore from the seabed. A collection tool then gathers up the ore from the floor and the resulting plume above it and delivers it to a vessel on the surface to be dewatered and processed.
CIM: What kind of factors did you have to take into consideration when designing these machines that you wouldn’t have had to if you were mining on land?
Johnston:[On the seafloor], there’s this massive pressure trying to crush everything. You’ve got to design for that massive pressure and if there is a single fault in one of your machines, you will know very quickly. It has to be pristine because there is no second chance; it will fail and get crushed.
Water at that depth also absorbs energy, so our cutting machines for the SMSs are designed to accommodate for the energy that gets lost [in the digging process]. On land, if you’ve got a pick and you smash a rock, first the pick jabs into the rock, and as it hits the rock, there is a shattering effect and the energy dissipates into the rock through that shattering motion. The deeper you get in the ocean, the more energy is absorbed by the water, so that shattering effect is very much reduced. So you have to calculate what they call the hyperbaric effect to know how to make up for that lost energy. That’s why the machines are so big and heavy.
CIM: Nautilus, with the help of various contractors, consultants, and companies, has designed and built three seafloor production tools. How do they work?
Johnston: The three machines perform different functions. The first machine is what we call the collection machine, and it’s designed to collect the already cut material and transfer it to the pumping and riser systems to get it up to the vessel. Then there are two mining machines that are quite different. We have what we call the auxiliary machine, which has a boom with four counter-rotating cutter heads that’s able to swivel and reach in different directions. It’s designed to go in the more rugged areas and make them more level. That’s done in preparation for the main cutting machine, the bulk cutter. It has rough teeth all over it and is designed to produce at a very high rate. It’s the heaviest of the machines and it uses that weight to cut at a very high rate.
Nautilus minerals has three seafloor production tools to mine deposits at the bottom of the ocean. From left to right: the collection machine, the bulk cutter and the auxiliary cutter. Courtesy of Nautilus Minerals
CIM: How are the tools you created SMS-specific?
Johnston: The machines are built to be big and heavy, and that weight gets transferred into the rock-cutting process. Nodules, [as opposed to SMS,] sit like potatoes scattered all over the seafloor, and the sediment they sit in has very minimal load bearing capacity. On land it would be like having to send machines onto a tailings dam. You couldn’t use the tools we have in that sediment unless you seriously accommodated for the weight with buoyancy.
CIM: What kinds of trials have you been undertaking with the machines since they were completed and delivered in 2015?
Johnston: As well as the functionality of the machines themselves for how they handle irregular ground and their collection capability – making sure that the specifications that we’re using in our mine plans are accurate with what the performance of the machine is – we’re also testing visualization technology [that allows the remote operator to see what the machines are doing underwater]. From the design concept phase through to build and delivery, there was about a six-year period, and in that time there have been massive changes in visualization technology, so we are looking at upgrading those functions.
CIM: What kinds of impacts do you think these machines will have on a deep sea environment and what is Nautilus doing to try to mitigate these?
Johnston: The machines will have an impact on the environment because they’re designed to extract rock from the seafloor, so we will be modifying the seafloor. We have a number of strategies to try to decrease our impact, like relocating organisms, putting down alternate substrates and reducing the plume. The machines are designed to limit the amount of plume because while they suck up the ore, they’re designed to also suck up the plume.
On land, the grades are getting lower and lower, and on the seafloor it’s actually the exact opposite. Our SMS site has a copper grade of nearly eight per cent and a gold grade of nearly seven grams per pound of ore. The average grade of a copper mine last year was between 0.5 and 0.6 per cent, so the grade of our deposits is about 20 times what the grade is on land. For the nodules [in the CCZ], it’s about one per cent copper, but it also comes with grades of 1.2 per cent nickel and 0.25 per cent cobalt. These deposits on the seafloor are the largest single deposits of copper, nickel, cobalt and manganese in the world. We only have to mine a very little bit on the seafloor to get the same results as huge pits on land.
In 20 years, the world will consume probably around 35 to 40 million tonnes of copper in a single year, which is probably more than all the copper mankind mined and consumed from the start of the Bronze Age up to the Industrial Revolution – about 4,500 years. We need it for transmitting electricity and we need it in our computers, mobile phones and our electric cars. So the intensity of the consumption of some of these key minerals that are all found on the seafloor is just going to continue to increase.
CIM: Because Nautilus will be the first company to mine the seafloor, industry leaders have said that there’s a race among other miners to be second. What is your reaction to that?
Johnston: We’ve got about 20 patents, some of them we hold jointly with other companies, so it’s not going to be a simple process for people just to wander in off the street and copy what we’re doing. It’s a bit like someone in the land mining industry having a patent over drill and blast and load and haul systems. If you controlled that, you’d have control over just about every operative mine on the planet. So if people are looking to be fast followers and want to look at our reports and talk to contractors that we used and things like that, they’d be able to move forward quicker than we did, but they’re also probably going to find themselves in court, too, because they’ll just be copying us.
CIM: What’s next for Nautilus?
Johnston: The ISA [which governs and regulates all mineral-related activities in seabed areas beyond the limits of national jurisdiction] probably isn’t going to have its [exploitation] regulations available for another couple of years, and we plan to be commercially producing [in PNG’s national waters] at the end of the first quarter of 2019, so we’ll already be mining by that time. But once the ISA’s regulations are finalized, we’ll put the foot on the accelerators to seriously develop the CCZ. We’ve got equipment designs sitting ready to put into action, so I’ve just got to get a bit further on Solwara-1, and once it’s built and tested and once we complete a bit more of that, then we’ll start to crank up some of the nodule engineering bits as well.
CIM: How has it been working with PNG and Tonga, the country that has authority over the area of the CCZ?
Johnston: Both have been very supportive. A seafloor mine can make a significant difference to a country like Tonga, which has a total population of about 110,000 people. So a single mine and its royalties can add significant value to the government’s treasury, and the employment that’s generated when we train and employ Tongan nationals to work in these mines is also valuable. PNG wants to see new mining technology developed, and they’re one of our partners in owning a lot of the new technology. They also want to see mines have less of an environmental impact because they have some very large mines on land, like Porgera, that have quite large footprints. Ours will be smaller.
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