Seabed harvesting for polymetallic nodules.

Diddy Cameron has a new enthusiasm.

Sponsored by the Government, a company called UK Seabed Resources has won the first commercial exploration rights over a 58,000 square-kilometre area of the Pacific, he announced. The licence was granted by the International Seabed Authority, the body governing mining outside territorial waters.

Late this summer, the company will start to hunt for those so-called polymetallic nodules, potato-sized rocks rich in minerals which are found on the seabed, some 4,000 metres under the Pacific waves. Also known as manganese nodules, they were first discovered in 1868, in the Arctic ocean, but are found on ocean floors around the world.

It\’s all very fascinating indeed. And there\’s certainly no problem at all with extraction of the metals from the minerals. However…..

I\’m always very hesitant about the \”energy\” argument. You know, sure, there\’s lots of metals around but the price will inevitably go up as lower grade ores require more energy to extract? Sorta peak oil meets mineral exhaustion, a favourite of certain greenies.

But I do think that it has some validity here. Manganese, the major component of these nodules, is around $3,000 a tonne at present (that\’s about right, if not exactly). And if you can get stuff up off the ocean floor through 4,000 metres of water for less than that then I\’d be astonished. Note that this isn\’t oil or gas coming up under its own pressure…..

Some of the South African gold mines are losing money simply because of this sort of equation. The ore down there is just fine but at 1 mile or more down the energy to get it to the surface makes the whole process uneconomic.

Most unconvinced that this will ever be economic. Quite apart from anything else there\’s so much stuff already available on land…..

14 thoughts on “Seabed harvesting for polymetallic nodules.”

  1. By the way, this idea is not very new – at least, Desmond Bagley’s second-to-last novel “Night of Error” from 1984 had a plot which involved trawling for nodules.

    And if I remember right, extractic metals from these nodules wasn’t really economical in that book either.

  2. And let’s not forget the damage that will be done to the flora and fauna…
    Just because it is ” a far away country… of whom we know nothing” .

  3. what do Greenpeace and the other eco-loons think of this? Is this the end of “the Greenest government ever”?

  4. In poly-metallic mines the mining costs are usually less than 10 percent of the total cost. The bulk of the costs are tied-up in the metallurgical processes. And one of the main drivers of the metallurgical costs is energy. Green Dave and his windmills with their erratic supply doesn’t stand a chance to pour one ingot.

    Manganese is so abundant, the end-users are very picky and like the ores to contain no contaminants that damage their furnaces? Marketing study anyone?

  5. Are n’t there any deposits of scandium on the seabed?

    Tim adds: Strangely, no. The hydroxide is insoluble in water so water action doesn’t lead to any concentrations of it.

  6. It’s the “sponsored by the government” gives the clue.
    Once you read those words, you just know it’s not going to be viable.

  7. Wasn’t this originally the cover story for the project from the early 1970s, where the US tried to retrieve a Soviet submarine from deep water? Howard Hughes built the Glomar Explorer to carry out the lift, with “harvesting manganese nodules” as her avowed purpose?

  8. Stranger still then that there is a piece on the Net entitled “Pacific islands seek protection from deep sea mining” which refers to Hawaii,Tahiti and whatever as likely sites for scandium .Perhaps they have n’t heard about the hydroxides!

  9. To what shall I compare deep water mining?

    Well … fish meal is $2000 a tonne or so.

    What about krill?

  10. Well, the depth per se is not a problem. The potential energy needed to raise a ton 4 km is roughly 40 MJ, which is the energy content of a little over a litre of gasoline.

    And given the oil and gas industry, remotely operating machinery on the sea bed is technologically feasible.

    Maybe the issue is the water resistance? Wading across a swimming pool is more tiring than walking the same distance on dry land. But you can avoid that if you run a continuous cylinder of moving stuff, so the water around it never has to move.

    The point about oil wells is probably not that the oil comes up under its own pressure, but that you only have to work in one fixed location. (More or less. Moves are infrequent, at least.) You don’t have to range over hundreds of square kilometres to pick it all up. If the issue is energy, it’s most likely the energy for the horizontal transport, not the vertical…

  11. So Much For Subtlety

    I have an alternative idea. We can build little robots who do nothing all day but crawl along the ocean floor picking up nodules of ore. Then we can build bigger ones that harvest them. Perhaps even bigger ones that prey on those. And if only we can teach them to reproduce – preferably by beaching themselves – we could have all the manganese we could ever want.

    Of course I think they should be powered by thermocouples warmed by nuclear waste. Just because. And because it would cause Hellen Caldicott’s head to explode. Which is always a bonus.

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