Deep Sea Nodule Mining

 

There are many areas in the deep deep ocean where the bottom is covered with mineral nodules. Some of the minerals in the nodules are ones that we need for the transition away from fossil fuels.  Ways are being developed to mine these minerals. 

 

Sept 2022. - Note that a new type of battery has been developed using no Co or Ni and using a Li, Fe P04, Mn chemistry.  It is reported to be  superior to other Li batteries  in terms of its longevity and safety.  Ocean bottom nodules are rich in Mn, Co, Cu, Ti and Ni and have high concentrations of Fe.  Some of them also contain Rare Earth Minerals.  Personally, I would sacrifice a little energy density in my EV battery for an increase in the longevity of the battery.  This latest version of a Li battery can be fully charged and  discharged with no added fade and if  not in use for long periods of time must be periodically charged.  50% is ideal for storage.

 

Note also that recycling technology for batteries is getting better and better.  This will eventually decrease the need for new mining.  However at present a lot of newly mined minerals are needed.

 

So far, the method of choice seems to be to lower a crawler down to the sea bottom that breaks the nodules into smaller pieces which are then sucked to the surface.  Along with the nodules comes quite a bit of bottom-water* and non-nodule particulates including burrowing organisms in the sediment.  The crawlers raise plumes of this particulate material which can settle over un-mined areas and smother the organisms there.  It consists of a little mineral matter and of the 'organic snow' that has accumulated over the eons. 

 *Which turns out to be potentially quite important

 

We seem to be conflating* deep sea nodule mining with bottom trawling.  They are quite different.  As is often the case, the devil is in the detail.  How you do something is often more important than the fact that you are doing it.

*Conflate - modern use "confusing one thing for another, whether they be similar or not"

 

 With bottom trawling for fish, clams and prawns, the same area is dragged again and again, never allowing the bottom fauna to recover.  In addition every square centimeter is dragged, eliminating untouched areas  that could re-colonize the dragged areas.

 

 With deep sea mining, the area can only be mined once.  When an area has been mined it will be many, many thousand, even millions of years before nodules will be found there in sufficient concentrations to mine again.  (And with our ever increasing output of green house gasses, year by year, we may well not be around then)

But as I said at the outset, the devil is in the detail.  For instance:

 

     We can legislate and enforce, that only a defined percent of the sea bed can be mined.  The nodule rich areas are so vast that this should not be a problem.  Companies that are not complying loose their license to mine.  This way, untouched areas can be left to re-colonize the mined areas.  Possibly even better, we could mine alternate strips.

 

     We must design the crawlers so that the dust they raise on the sea bed is confined and sucked to the surface.  This is to avoid smothering adjacent un-mined areas.  If this material is discharged at the surface it will be dispersed far and wide by currents which go different directions at various depths and will be diluted.  By the time this fine material reaches the bottom, if it ever does#, it should be very little more than the background level of sedimentation.    As an added measure we could  spray the bottom water over the surface of the ocean to start the dispersion*.

# Passive filter feeders in the photic zone will likely take up this source of organic material. The population of such filter feeders will increase in an area where this new source of  material is available.  This would likely form the foundation for a food web.

*Bottom water will be denser than surface water so if released in a solid stream, will likely plunge downward.  Spraying it on the surface will facilitate the mixing with surface water in the photic  zone, allowing time for filter feeders to take up the particulate material and for phytoplankton to utilize dissolved nutrients in the bottom water.  The ocean surface above areas with nodules tend to be ocean deserts with respect to nutrients.  A nodule mining operation will likely  become a biological oasis in this desert.

 

And there may be a couple of benefits on the sea floor:

 

     A climax ecology is somewhat boring.  A certain level of disruption (a tree falls in the jungle) increases biodiversity by allowing pioneer species to  flourish.  Mined-out areas, as long as they are limited in terms of the percent of an area that is mined, are ripe for colonization by pioneer species followed by a sequence, that eventually leads back to a climax ecology.  The question is not whether to mine or not mine but rather what percent to mine and how much to leave.

 

     Bottom water, (as is well known from areas where natural up-welling occurs), powers massive productivity.  A good example is the area off the coast of Peru where up-welling occurs during the la-Nina and El-Nino-neutral years.  It is one of the most productive areas of ocean in the world.   If bottom water, from nodule mining, discharged into the photic zone with its dissolved nutrients and fine organic dust it will likely have the same effect as a fecal plume from a whale.  As mentioned, the discharge water could be sprayed across the surface of the ocean to begin the mixing and to avoid having this water plunge back down into the abyss. 

 

As I said at the outset, the devil is in the detail.  Instead of thinking 'bottom trawling' when we hear 'nodule mining' we should look at the detail and the opportunities and ways of benefiting from the nodule mining.  It would likely be  too expensive to pump water and sediment from the deep ocean just to stimulate a plankton bloom in mid ocean deserts and to reap the  benefits that would follow from this.  It is a different story if we can catch a ride on a commercial operation that gets its finance from the sale of nodules and as a by-product, creates an oasis in the ocean desert.

I would think that an initial experiment would be to suck up bottom water with the fine particulate material from the abyss and spray it on to the surface of the ocean for  a couple of months to see what develops.  This should be done from a surface ship that can maintain its geographical position.  The surface of the ocean is always moving so the surface water will be flowing past a stationary ship.  The bottom material will not be discharged into the same water but into a moving stream.  Samples should then be taken along the discharge stream to see what develops. I bet it will be a succession starting with phytoplankton and small filter feeders and ending with fish and even marine mammals.

Note:  I just learned from this video that the bottom is rich in worms which cycle the snow of organic material which is constantly falling through the water and these worms form the bases of a rich food web.  They would likely be sucked up along with the nutrient rich deep ocean water.  On one hand, it is important that we have a mining system that mines alternate strips, leaving strips untouched.  On the other hand, this rich source of food, sucked up to the surface will soon be utilized by surface marine life in what is at present a marine desert in terms of available food.  Island countries in the Pacific could find a rich surface fisheries resulting from the mining of these nodules which develops downstream from the surface ship.  It is vital that the 'hurricane' of  dust they raise is confined and sucked to the surface and not allowed to smother the un-mined strips.

 

 

 

 

Ocean Nodule Mining

Here in New Zealand, an application has been rejected to mine the mineral nodules in our surrounding deep ocean.  I think that the powers-that-be have little sense of proportion.  Let me be clear.  I am not talking about the mining of mineral sands in shallow water.  That is another story.  I'm not saying that shallow water mineral mining is bad or good.  Just that it is another story and has to be examined separately on its merits.

These mineral nodules in the deep ocean lie on the surface of the ocean bottom.  They contain a range of very valuable minerals in concentrated form.  

Let's assume for the sake of the argument, the worst case scenario; that the hovering up of the nodules and the return of the gangue* totally smothers that area of sea bottom.

*waste bits and pieces that are not mineral nodules

No polluting chemicals are used. No excavation of the sea bottom occurs. At the most extreme, the returning waste will smother whatever is living on that area of sea bottom.  The most extreme possibility is that the area is rendered sterile.  Once the area has been mined it can't be mined again for many thousands of years.  That is how long it takes for the nodules to grow.  Here is where it gets interesting.  Let me sidestep for a moment.

Let's look at a mature forest; one that has reached it's climax state.  Competition has gone on between the various plants (trees, epiphites etc.) and the various animals and whatever survived makes up the environment.  Many species have fallen by the wayside in this competition.  Then a giant tree falls or a fire burns out a section of the forest.  Note we are not talking about logging in which massive areas are clear felled and as soon as the new growth is large enough, logged again but rather a bit of the forest that is cleared.

All sorts of pioneer species start to grow in the cleared area and the forest is greatly diversified.  Animals which do better in a pioneering forest return.  The forest is now much more diverse and for that matter much more interesting than it was.

The same thing can be expected on the ocean bottom.  Note that here we are not talking about A) the huge areas which are cleared by bottom trawling or B) the trawling again and again of the same area, never letting pioneering species  establish themselves.
 
It takes that long for nodules to grow.  The area gets recolonized by whatever lives in the area and whatever larvae drift by from afar and over time goes back to its original state.  If it follows the path that is observed in many ecologies from pioneer to climax state.  The over all area is enriched by a small part of it being re-set to its beginning and going through a succession toward its climactic state.

Compare that with bottom trawling which we do allow.  You scrape the bottom clean and then do it again and again and again.  The area never has a chance to recover.  If we want to do something for the bottom of the ocean we should ban bottom trawling and only allow long line methods.

We need a sense of proportion when deciding what to allow and what to forbid.  Nodule mining has to be on the extreme benign end of the spectrum and a good case can be made for it even being beneficial.  Bottom trawling is at the disastrous end.

This whole episode is similar to the stramash we had over indoor dairy farms in the MacKenzie country.  Yes, indoor dairy farms can be bad for the animals and truly horrible places.  However they can  be much better for the animals, far more ecologically friendly and, would you believe, more profitable.  The devil is in the details.

I saw a similar situation in Canada.  I met a fisheries biologist who should have known better.  He was off to break up a beaver dam in the belief that they were bad for fish stocks in that river.  Hydro dams are bad so, so must be a beaver dam.  I asked him why, before the Hudson Bay Company era, when beaver dams were in pretty well every location where  one could be built, the salmon runs were many orders of magnitude larger than they are today*.  He still went out to break up the beaver dam but hopefully it got him thinking.

Biology is complicated and intricate and the first knee jerk reaction to a situation is not often the best one.  Each situation has to be examined in detail and intelligent decisions make.  Much of our use of the planet is disastrous but not all of it.

*In about  1888, the Hudson Bay Company initiated a policy to exterminate the fur bearing animals of the Columbia Catchment to deny an economic base for America in that area.  The beavers were first to go.  Salmon runs plummeted. 

More famous is the situation with wolves.  Farley Mowat deals with this in his very amusing book Never Cry Wolf.  Canadian wildlife biologists were convinced that the wolves were decimating the caribou and put a bounty on them.

Of course we then have the example of the destruction of the fisheries of the Grand Banks under the supervision of Canadian fisheries biologists, a group of people who tend to be as green as they come.  Through a combination of corporation short sighted greed and faulty science by the best scientist of the day, the Grand Banks were trashed. 

I am a greenie through and through.  I always support the Green Party, my hero is George Monbiot and my passion is rewilding in general and beavers in particular but the greens do sometimes do go off half cocked with knee jerk reactions to things without examining the deeper implications (unexpected consequences) of their actions.  As greens we must choose our battles and carry them through to the  end and not get distracted by unimportant causes or causes in which we are  on the wrong side of the argument.

We must realize that humans are the story telling ape and get better at telling the story.  It is far more interesting than the sound bite.

The green parties of the world are our only chance in a world we seem to be determined to trash.  They are usually the only party with a vision that extends beyond a single election term.  We desperately need them to make the right choices, hold their governments feet to the fire, speak truth to power and just maybe they will succeed in pulling us out of mad rush to exterminate ourselves or at least to end the fantastic advances we have made since we have shaken loose the bonds of religious fanaticism.