Riches under the sea

C&I Issue 6, 2012

In January 1982, the deepwater submersible Alvin dived into the Gulf of California to explore newly discovered black smokers. At a depth of 2000m on the seafloor, these pipe-like structures – resembling dirty industrial chimneys – build up when scorching hot spring water vented as ‘smoke’ mixes with cold sea water and precipitates stacks of minerals, some industrially desirable.

Steve Scott, of the University of Toronto, Canada, was one of the first geologists to look upon these natural wonders. ‘I looked out the window of the submersible and I realised that not only was this an exciting thing to see, but that these were the mines of the future,’ says Scott.

Now, hundreds of millions of dollars and several false starts later, the stage is set for this vision finally to become reality. Nautilus Minerals plans to begin extraction of massive sulfide deposits, built up by black smokers off the east coast of Papua New Guinea, in 2013. These sulfides – iron, copper, zinc, silver and gold, along with sulfates, silica and occasionally lead – are precipitated when hot metal-laden hydrothermal fluid, spewed from the chimney at about 350°C, mixes with 2°C ambient seawater.

Nautilus initially intends to extract gold, copper and silver off New Guinea, though the company believes there may be significant deposits of zinc; its mining robots will work at a depth of around 1600m. 

‘We currently have an indicated resource of 1.3m t and we expect to find more in coming years,’ says Joe Dowling of Nautilus, adding that it is not yet possible to estimate how much ore is likely to be available. Scott and his Australian colleague Ray Binns discovered this site of seafloor massive sulfides in 1996; they were searching not as prospectors, but as research scientists seeking to better understand the volcanic-hosted massive sulfides on land by studying their relations at sea. Nautilus has named this deposit Solwara 1, but there are several more deposits in the area.

More than 2.5m t of ore from the deposit has been surveyed and samples so far average about 7% copper and 6g of gold per tonne. Terrestrial deposits generally yield only about 2% copper and 1g of gold per tonne. ‘We found deposits worth over a billion dollars,’ Scott estimates. Nautilus is now exploring off Tonga, Fiji, Vanuatu and the Solomon Islands, and its market capitalisation is in the hundreds of millions even though it is a start-up company. 

‘We knew it [Solwara 1] was pretty big,’ Scott recalls, ‘but now that Nautilus has explored it, it is much bigger than we had imagined. And people are making new discoveries all the time.’

How many black smokers are lying on the Earth’s seafloor is not known; Russian scientists reported finding seafloor massive sulfides on the mid-Atlantic ridge and claim that at least one of the deposits may hold millions of tonnes.  But huge areas have yet to be properly prospected. 

About 40% of Earth’s surface is deep ocean basins beyond the continental slope at water depths typically in excess of 2000m. The surface area of the Pacific Ocean alone is equal to that of all the continents. Not surprisingly, the prospect of finding more deposits has attracted attention around the globe. In China, for example, China Minmetals – the country’s largest metals trader – says it has also carried out R&D work into deep-sea mining exploration and exploitation to meet the growing demand for minerals and metals.

Australian David Heydon, the founder of Nautilus, goes as far as to question the sense in looking for more minerals on land, which has become more difficult, costly and challenging.  ‘Obviously on land they have mined all the good we are down to the high end, costly material that’s left,’ he says. Increasing demand for resources can only be met on land if mining is to go back underground, move into politically unstable countries and environmentally-sensitive areas like rain forests, Heydon says; it’s better to go to sea.

‘All that good stuff we use to mine hundreds of years ago on land is still down there on the seafloor,’ adds Heydon, who is no longer with Nautilus but is now founder of Deep Green Resources. Deposits that he is exploring in international waters have twice as much copper as current copper mines, for example, and also contain valuable bonus materials, such as nickel and manganese. There are also logistical advantages to working at sea, he claims: no need to punch a shaft through solid rock; instead push a pipe through water to the ocean bottom, pull material up and it is on a ship, ready to go. 

Resources presently gathered from shallow sea beds include diamonds off Namibia and tin off Indonesia. Known deposits of heavy minerals like titanium and zirconium attract some attention, but the big fish is manganese deposits in the Pacific.

Manganese nodules

The survey ship HMS Challenger first discovered manganese nodules in the depths of the Pacific Ocean in the 19th century. Experts say the nodules resemble golf balls lying in a muddy field, but each is made of concretions of minerals such as manganese, iron, nickel, copper, cobalt, vanadium and molybdenum, which have grown up around an object. Lying at a depth of between 4500 and 5500m, a treasure trove of sought-after elements is waiting to be brought to the sea surface.

‘In the 1970s, four different consortia mapped and surveyed, and did environmental studies, and then actually trial-mined these deposits. They brought up in total 2000t of these nodules,’ says Heydon. ‘The reason they didn’t go ahead [with extraction in the 1970s] was because they couldn’t get secure title.’

Manganese is essential for steel production and is the fourth most used metal in the world today. There are vast deposits on the seafloor, in the so-called Clarion-Clipperton Zone between Mexico and Hawaii in the Pacific.

Working in the deep sea is not a ‘put off’. The oil and gas industry has already pioneered working at depth. Nautilus plans to deploy three machines, operated by remote control. Operators sitting on a ship stationed above the deposit will control mine-bots on the seafloor: an initial cutter for clearance; a bulk cutter to do most of the work; and a machine to collect and transport the material to a pumping station. The material will be then pumped up in slurry form to the ship, where it will be de-watered and set to shore for processing.  For nodules, robots will roam the seabed. 

Eight countries have applied to the International Seabed Authority for permission to explore areas the size of Scotland in the Pacific for manganese nodules. So far, countries that have secured title from the International Seabed Authority include France, Germany, Korea, Japan, India, Russia, China and a consortium of countries including Cuba.

Meanwhile, Heydon is looking to massive sulfides in the southwest Pacific and is working with the tiny Pacific island of Nauru, which has claimed an area of seafloor the size of Scotland.  So far, the Seabed Authority has granted titles for two types of deposits – seafloor massive sulfides and the manganese nodules – but other possibilities are opening up.

Heydon set up Deep Green Resources in anticipation, and he is looking to build a processing plant, which he claims will be environmentally benign. He points to nickel for comparison. Remaining land deposits of nickel lie beneath equatorial rain forests, he warns, and mining nickel laterite deposits produces an enormous amount of waste. 

‘It’s a waste of chemicals, a waste of energy and they have to bury the waste. In our process, we have zero waste.  Everything that we process we can sell,’ he says, because the nodules are 50% metal oxides and the rest is silicates. The deposits are 1.3% nickel, 1.1% copper, some cobalt and 29% manganese, with manganese making up half of the value. 

Heydon claims his firm has spent the past 12 months investigating and developing new chemical processes that recover the manganese, as well as the copper, nickel and cobalt – minerals that will be in demand from the new green economy.  He predicts harvesting of the nodules will begin ‘some time in the next 10 years, hopefully sooner,’ and says a lot will rely on the approval process and completing environmental studies.

Shortages ahoy

Meanwhile, the demand for minerals and metals continues to grow unabated, with projected shortages expected to disrupt entire supply chains and national economies, according to a PricewaterhouseCoopers (PwC) report published in late 2011: Minerals and metals scarcity in manufacturing: The ticking time bomb

Resource scarcity, particularly metal and mineral scarcity, has gone up the agenda of executives around the world, says Malcolm Preston, global head of sustainability services at PwC. ‘They haven’t suddenly become scarce, but the awareness of what is going on has risen significantly.’

Although some Asia Pacific countries, especially China, have abundant reserves of scarce minerals and metals, the expected impact of scarcity on companies in these countries over the next five years is substantial (53%), the report notes.

The survey showed that renewable energy, automotive, and energy and utilities, are currently experiencing instability of supply, with aerospace, high tech and infrastructure expected to see a steep rise in instability of supply from now to 2016. The percentage of companies that expect to be affected by this scarcity will triple in the chemicals industry, and double in the renewable energy and high-tech sectors, the report says.

So could the answer to these worries, at least for some of the resources, lie on the seabed?  Preston, who trained in oceanography before joining PwC, expresses concern about the environmental issues attached to any deep sea mining. These nodules grow over millions of years, so they cannot be harvested in a sustainable way, and there are many unknowns when it comes to life in the deep, he says.

‘Are you really going to wait or rely on ocean floor mining? Is that your business plan?,’ Preston asks. ‘I’m a big fan of businesses trying to find new and innovative ways of doing the same things rather than just trying to find more stuff to dig up.’

But, speaking at a meeting in Lisbon in late 2011, Jonathan Lowe, exploration manager at Nautilus, endorsed academic research by independent biologists. He said the company plans to seek large prospecting licences, but then occupy small sites for just two to three years. ‘If we don’t do this right, we destroy it for ourselves,’ he said.

Rich deposits of rare earths

In late 2011, Japanese researchers reported finding extremely rich deposits of rare earth minerals and yttrium on the Pacific seabed. They estimated that just 1km2 of deposits would deliver one-fifth of the total amount currently consumed globally every year.

‘The rare earths are generally mixed with the mud,’ says Yasuhiro Kato, associate professor of Earth science at the University of Tokyo. ‘Uptake of rare earth elements and yttrium by mineral phases such as hydrothermal iron-oxyhydroxides and phillipsite seem to be responsible for their high concentration,’ he adds, meaning that they can be readily recovered from the mud by simple acid leaching.

The deposits lie mostly at a depth of 4000 to 5000m, but Kato believes the mud can be developed as a mineral resource and could be piped to the surface. ‘Many big Japanese companies have a great deal of interest in our paper. We have already started a collaborative project with engineering firm MODEC and Mitsui & Co.,’ he says.

The European Union listed some of these elements among 14 economically important raw materials, including rare earths, cobalt, beryllium and magnesium. A handful of countries like China (rare earths), Russia (platinum group metals), and the Democratic Republic of Congo (cobalt) are the predominant suppliers of some of the materials which has led to concerns over security of supply. China shocked Japan in 2010, for example, by halting shipments of rare earths, raw materials vital for many high-tech goods.

International waters – international law?

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