Stories
Slash Boxes
Comments

SoylentNews is people

posted by chromas on Thursday July 02 2020, @04:30PM   Printer-friendly
from the where-the-mother-lode-gives-birth? dept.

Geologists identify deep-earth structures that may signal hidden metal lodes

If the world is to maintain a sustainable economy and fend off the worst effects of climate change, at least one industry will soon have to ramp up dramatically: the mining of metals needed to create a vast infrastructure for renewable power generation, storage, transmission and usage. The problem is, demand for such metals is likely to far outstrip currently both known deposits and the existing technology used to find more ore bodies.

Now, in a new study, scientists have discovered previously unrecognized structural lines 100 miles or more down in the earth that appear to signal the locations of giant deposits of copper, lead, zinc and other vital metals lying close enough to the surface to be mined, but too far down to be found using current exploration methods. The discovery could greatly narrow down search areas, and reduce the footprint of future mines, the authors say. The study appears this week in the journal Nature Geoscience.

[...] The study found that 85 percent of all known base-metal deposits hosted in sediments-and 100 percent of all "giant" deposits (those holding more than 10 million tons of metal)-lie above deeply buried lines girdling the planet that mark the edges of ancient continents. Specifically, the deposits lie along boundaries where the earth's lithosphere-the rigid outermost cladding of the planet, comprising the crust and upper mantle-thins out to about 170 kilometers below the surface.

Up to now, all such deposits have been found pretty much at the surface, and their locations have seemed to be somewhat random. Most discoveries have been made basically by geologists combing the ground and whacking at rocks with hammers. Geophysical exploration methods using gravity and other parameters to find buried ore bodies have entered in recent decades, but the results have been underwhelming. The new study presents geologists with a new, high-tech treasure map telling them where to look.

Journal Reference:
Mark J. Hoggard, Karol Czarnota, Fred D. Richards, et al. Global distribution of sediment-hosted metals controlled by craton edge stability, Nature Geoscience (DOI: 10.1038/s41561-020-0593-2)

-- submitted from IRC


Original Submission

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 2) by PiMuNu on Thursday July 02 2020, @04:51PM (41 children)

    by PiMuNu (3823) on Thursday July 02 2020, @04:51PM (#1015446)

    "100 miles or more down in the earth"

    "close enough to the surface to be mined"

    TFA was not terribly clear to me how deep they really are and the journal article is paywalled...

    Starting Score:    1  point
    Karma-Bonus Modifier   +1  

    Total Score:   2  
  • (Score: 5, Informative) by c0lo on Thursday July 02 2020, @05:04PM (27 children)

    by c0lo (156) Subscriber Badge on Thursday July 02 2020, @05:04PM (#1015448) Journal

    FA was not terribly clear to me how deep they really are

    170-200km seems to be the "sweet spot".
    For comparison, the deepest bore on Earth is at 12,262 metres (40,230 ft) [wikipedia.org]

    and the journal article is paywalled...

    The preprint is available [eartharxiv.org].
    And so is the data set [osf.io], if you want to plot the maps yourself. Or just to mirror it, just in case.

    --
    https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
    • (Score: 3, Insightful) by Freeman on Thursday July 02 2020, @06:10PM (25 children)

      by Freeman (732) on Thursday July 02 2020, @06:10PM (#1015470) Journal

      There's a big difference between 12.2km and 170 - 200km. Also, they were just doing it for science as it were. To do something like make a bore hole 100km down, to search for good places to get X metal. Yeah, that's getting a lot more into science fiction than practical business.

      --
      Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
      • (Score: 2, Interesting) by Anonymous Coward on Friday July 03 2020, @12:10AM (9 children)

        by Anonymous Coward on Friday July 03 2020, @12:10AM (#1015601)

        You have no idea. Having experience with bore holes going down just shy of 20k, I can say there is a big difference between a shallow well between 5k and 8k deep and a 35k deep on. I forget which oil company did that, but I heard they achieved a 35k.

        The difficulty is that you have to, segment by segment, lower the whole drilling apparatus into the ground. At the tip is the drill bit, and down the inside and outside of the pipe flows the "lubricant" as it were. This is what results in the constant flow of drilling mud to the surface that is analyzed.

        The taller your whole stack of pipes is, the greater amount of pressure on the joints, and the tip of the drill bit. That 20k foot well had one of the gnarliest SOBs I'd ever seen. Engineers rambled on about the strength of the tips, etc. Built for extreme pressures, heat, and a high enough hardness to withstand the rocks being drilled into. Those joints are simple threads, but they were impressive in their sizes and strengths as well.

        There is a logical limit I'm sure some engineers could calculate.

        1. Limit of the joints. Heat and pressure, and the strength to withstand torsional(?) forces
        2. Torsional limits at the surface. How strong are your engines, how much torque can you generate?
        3. Fluid dynamics. You're manipulating a 100 mile stack of water mixed materials, assuming normal methods. Do you have machines and processes that can generate the level of suction(?) required? (I say that because I don't know if the pressure of the drill head is enough to push the fluid to the surface). In any case, you need to deal with fluid dynamics for something that tall with obscene pressures at the bottom
        4. Drill head. You're going to need something that makes mine look like tissue paper to operate at the temperatures and pressures found at 100 miles deep
        5. Drill head swapping. You never complete a well with just one. Do you have enough strength to lift the whole stack? Is your drilling rig built to do that?
        6. More shit I'm not thinking about stoned on a lazy Thursday afternoon....

        Ohhhh! LOL

        The final one.

        Diminishing returns. If it takes you X days per 1 mile of stack to swap a drill bit, and each drill bit handles say 1 mile, how many days to drill 100 miles? We didn't get a 20k ft well drilled in just one day.

        • (Score: 2) by c0lo on Friday July 03 2020, @12:47AM

          by c0lo (156) Subscriber Badge on Friday July 03 2020, @12:47AM (#1015614) Journal

          But then again, it's a difference between drilling a borehole and sinking a well [ecpgroup.com].
          I'm not sure someone tried to sink a well at 170 km depth**, so I can't say we'll know all the problems need to be solved - temperature and level of pressure making rocks behaving like a viscous fluid [stackexchange.com] are already on the list.

          ** actually, I'm pretty sure nobody tried, otherwise we wouldn't be discussing this.

          --
          https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
        • (Score: 1) by khallow on Friday July 03 2020, @12:53PM (7 children)

          by khallow (3766) Subscriber Badge on Friday July 03 2020, @12:53PM (#1015730) Journal

          The taller your whole stack of pipes is, the greater amount of pressure on the joints, and the tip of the drill bit. That 20k foot well had one of the gnarliest SOBs I'd ever seen. Engineers rambled on about the strength of the tips, etc. Built for extreme pressures, heat, and a high enough hardness to withstand the rocks being drilled into. Those joints are simple threads, but they were impressive in their sizes and strengths as well.

          Notice the key property here, energy transferred over great distances mechanically (such as a 100 km long stack). A lot of these problems go away, if the forces applied are incremental and local. That is, the drill bit isn't experiencing forces from the rest of the kilometers of stack on it because they are supported in some other way (near neutral buoyancy probably). All you really need is a drill (with a short stack) with sufficient greater density than the rock it's drilling into.

          Similarly 100 km of fluid dynamics is much harder than 100 1 km stretches of fluid dynamics. There are ways to delink dynamics of a long pipe so you don't have to worry about large scale fluctuations breaking it. Also make sure the internal pressure is near equal to the external pressure.

          The other big problem is heat. Rock isn't getting harder at those depths, but softer due to the heat. The problem is that the drill bit (assuming you continue to use a solid drill bit - there are other approaches like drilling with a pressurized fluid) is getting softer as well, also due to the heat. An ability to move massive amounts of heat to the surface would solve that problem because you could cool the bit to traditional working temperatures while not cooling the rock that is being drilled. The drill bit would experience greatly increased life span.

          Further, drill bits have well understood lifespans. If it takes a while to transport a drill bit down, then why not transport numerous bits down so that you have a pool of bits to use when the current one fails? It's far quicker to transport a drill bit tens of meters than it is to transport it 100 km.

          I think this really is not that hard aside from heat transport and maybe shear due to movement of the crust. A near neutral buoyancy structure (2.7-3 metric tons per cubic meter for crust [joidesresolution.org], somewhat greater for upper mantle, maybe around 3-3.3 [oup.com] metric tons per cubic meter?) is supported by the surrounding rock rather than having to support the mass of the structure. Pumping fluids or moving solid parts around can similarly be done incrementally.

          • (Score: 2) by Immerman on Friday July 03 2020, @02:07PM (6 children)

            by Immerman (3985) on Friday July 03 2020, @02:07PM (#1015755)

            > If it takes a while to transport a drill bit down, then why not transport numerous bits down so that you have a pool of bits to use when the current one fails?

            Where are you going to put them? The hole is the same size as the drill bit, and to use a new bit you must first remove the old bit. I suppose you could potentially design a "stacked bit" where you could disengage the dull front bit to let the next bit take over - but that next bit is going to have to either drill through the first one, or back up and drill around it.

            • (Score: 1) by khallow on Saturday July 04 2020, @03:23AM (5 children)

              by khallow (3766) Subscriber Badge on Saturday July 04 2020, @03:23AM (#1015990) Journal

              Where are you going to put them? The hole is the same size as the drill bit

              Well, sounds like we have another big challenge then. While it might be possible to assemble a drill bit wider than the hole it came in under the high performance conditions of 100 km down, we can also drill parallel holes and store stuff in them as well as use that for the space needed to swap out drills and such.

              All I can say though is that if you're pulling drill bits all the way to the surface to replace them, then you're doing it wrong.

              • (Score: 2) by Immerman on Saturday July 04 2020, @09:23PM (4 children)

                by Immerman (3985) on Saturday July 04 2020, @09:23PM (#1016255)

                >All I can say though is that if you're pulling drill bits all the way to the surface to replace them, then you're doing it wrong.

                If you're trying to dig a 100mile borehole, probably not. But if you're drilling, there's not a whole lot of other options - that shaft is transmitting a lot of torque, you'll be lucky if you can use a stack of bits that can break away on demand (rather than breaking away whenever you hit something hard). You're almost certainly not going to be able to park a bunch of replacement bits in a side hole and re-connect to them when needed - not in a semi-liquid environment of packed with mud and shattered stone.

                • (Score: 1) by khallow on Sunday July 05 2020, @01:51AM (3 children)

                  by khallow (3766) Subscriber Badge on Sunday July 05 2020, @01:51AM (#1016347) Journal

                  that shaft is transmitting a lot of torque

                  Why would it be transmitting any torque at all? The drill bit itself doesn't need to generate net torque. And the force needed to drill can be generated locally (rather than mechanically through a rotating shaft) meaning most of the pipe wouldn't be experiencing any force or torque from the drilling itself. And if you made most of the pipe near zero buoyancy, any segment wouldn't generate much force on the rest of the pipe.

                  you'll be lucky if you can use a stack of bits that can break away on demand (rather than breaking away whenever you hit something hard). You're almost certainly not going to be able to park a bunch of replacement bits in a side hole and re-connect to them when needed - not in a semi-liquid environment of packed with mud and shattered stone.

                  Rather than be an impossible thing, this sounds like a way to implement things. The semi-liquid environment already moves things around. Stack of bits doesn't sound workable, but replacing a drill bit, by pulling back the assembly and replacing it, does sound to me like it would be viable.

                  My thinking is that in the long run, many decades down the road, one could create huge shafts and complex transportation systems capable of managing multiple drills at the same time at various levels of the system (to widen parts of the system or drill deeper), and vast underground infrastructure to mine these alleged deposits. And all of this could be a natural incremental improvement of technology we could deploy in the near future (well, have to make the stuff first).

                  • (Score: 2) by Immerman on Sunday July 05 2020, @02:48AM (2 children)

                    by Immerman (3985) on Sunday July 05 2020, @02:48AM (#1016351)

                    Net torque is what lets the bit cut through rock - without it it your hole doesn't get any deeper.

                    Semi-liquid is fine - pieces of shattered stone are NOT. And inevitable.

                    • (Score: 1) by khallow on Sunday July 05 2020, @03:51AM (1 child)

                      by khallow (3766) Subscriber Badge on Sunday July 05 2020, @03:51AM (#1016377) Journal

                      Net torque is what lets the bit cut through rock

                      Torque not net torque is what lets the bit cut rock. You can, for example have two or more drill bits rotating counter to each other so that they are cutting rock, but generating zero net torque in the process.

                      Semi-liquid is fine - pieces of shattered stone are NOT.

                      Because?

                      • (Score: 2) by Immerman on Sunday July 05 2020, @01:31PM

                        by Immerman (3985) on Sunday July 05 2020, @01:31PM (#1016498)

                        Because you're not plugging a connection together with a bunch of gravel in the way.

      • (Score: 2) by driverless on Friday July 03 2020, @02:09AM (14 children)

        by driverless (4770) on Friday July 03 2020, @02:09AM (#1015627)

        Yup. May as well go for the earth's core, there's a lot of metal in that.

        • (Score: 0) by Anonymous Coward on Friday July 03 2020, @02:22AM (13 children)

          by Anonymous Coward on Friday July 03 2020, @02:22AM (#1015634)

          It would be truly idiotic to attempt such a thing. If you were successful, you'd doom the planet to extinction. If you fail, huge volcano.

          • (Score: 1) by khallow on Friday July 03 2020, @12:59PM (12 children)

            by khallow (3766) Subscriber Badge on Friday July 03 2020, @12:59PM (#1015732) Journal
            The easier way would be for Von Neumann machines to take the Earth apart from the surface on down. It'd get easier as more mass is orbited. It'd take a lot of licks to get to the center of this pop, but a Von Neumann swarm has a lot of tongues.

            If you were successful, you'd doom the planet to extinction.

            And your point is? I don't see even the slightest need to mine the Earth's core today. But in half a billion to billion years, the Earth is doomed anyway. Might as well make something useful of it when that time comes.

            • (Score: 2) by Immerman on Friday July 03 2020, @02:19PM (11 children)

              by Immerman (3985) on Friday July 03 2020, @02:19PM (#1015758)

              >But in half a billion to billion years, the Earth is doomed anyway.

              Hardly. It'd be far easier to move the Earth than mine it away - we even have a convenient gravitational tugboat already handy in the moon, we just need to install some engines and we can tow the Earth around to keep it in a nice temperate orbit around the aging sun and eventual expanding red giant. Assuming some sort of reasonably efficient mass conversion we could even install massive lights on the near surface of the moon to simulate the sun and tow the Earth through interstellar space to a new star - or just soar across the galaxy indefinitely, occasionally nabbing a new moon as we pass a star system to keep the system powered.

              As interstellar world-ships go, an actual planet is hard to beat, so long as you're not in a hurry to get anywhere.

              • (Score: 1) by khallow on Sunday July 05 2020, @03:22AM (10 children)

                by khallow (3766) Subscriber Badge on Sunday July 05 2020, @03:22AM (#1016364) Journal

                As interstellar world-ships go, an actual planet is hard to beat

                Except by a bunch of smaller world-ships with say, a billion or more times the surface area of Earth.

                • (Score: 2) by Immerman on Sunday July 05 2020, @02:27PM (9 children)

                  by Immerman (3985) on Sunday July 05 2020, @02:27PM (#1016511)

                  So long as you're okay with all the vulnerabilities of flying in a massive tin can. Not that a planet is completely invulnerable - but it has a very different set of vulnerabilities, and in general is far more robust - especially if you can control the brightness of the "sun" to compensate for environmental fluctuations.

                  Don't get me wrong - I'd love to see humanity living in clouds of O'Neill cylinders with vast floating microgravity cities down their cores... but artificial habitats just aren't robust enough to allow chaos to run free. And while there are many benefits to a controlled environment, I dearly hope we never lose our appreciation for the power and bounty of nature unchained - and nature can't truly exist in the limited confines of a controlled environment.

                  It's not like there's any shortage of raw materials floating around to make artificial habitats - including all the other planets we don't decide to terraform. But I strongly hope that the oasis that gave us birth will maintain a certain sentimental value.

                  If nothing else, if allowed to lie relatively fallow the rich native biodiversity could provide a steady stream of new intelligent species to join us, assuming we're not so xenophobic as to want our own species to be the only intelligent life in our corner of the galaxy. How many million-year epochs do you suppose it takes on average before a new technological civilization arises? Ours is the only one we know of so far (assuming we include all our hominid cousin species), but it's only been a few hundred since the Cambrian Explosion gave birth to a huge diversity of complex life - and there'll be millions more to come before the red dwarves start burning out.

                  • (Score: 1) by khallow on Sunday July 05 2020, @11:37PM (8 children)

                    by khallow (3766) Subscriber Badge on Sunday July 05 2020, @11:37PM (#1016714) Journal

                    So long as you're okay with all the vulnerabilities of flying in a massive tin can.

                    Such as massive redundancy?

                    • (Score: 3, Interesting) by Immerman on Monday July 06 2020, @01:06PM (7 children)

                      by Immerman (3985) on Monday July 06 2020, @01:06PM (#1016994)

                      Compared to a planet? Not hardly. Not on an individual basis anyway.

                      It's the difference between spreading your eggs across a multitude of tiny fragile baskets, and putting them all in one heavily armored nigh-indestructible bunker.

                      If your primary concern is that some of the eggs survive (aka the survival of the species), lots of fragile baskets may be a better bet - though given the scale of astronomical disasters there's an awful lot of things (like a nearby supernova or other such high-energy event) that could easily kill everything in all the baskets, while only killing the facing surface of a planet.

                      On the other hand, if your primary concern is the survival of a specific handful of eggs (yourself and your family), then putting them in the bunker radically increases their safety.

                      • (Score: 1) by khallow on Tuesday July 07 2020, @12:36PM (6 children)

                        by khallow (3766) Subscriber Badge on Tuesday July 07 2020, @12:36PM (#1017581) Journal

                        Compared to a planet? Not hardly. Not on an individual basis anyway.

                        Yes, compared to a planet. And how could I be thinking of redundancy on an individual basis?

                        If your primary concern is that some of the eggs survive (aka the survival of the species), lots of fragile baskets may be a better bet - though given the scale of astronomical disasters there's an awful lot of things (like a nearby supernova or other such high-energy event) that could easily kill everything in all the baskets, while only killing the facing surface of a planet.

                        You don't need the full thickness of a planet to shield against such high energy events. And one of the advantages of lots of slightly more fragile baskets is that you can spread the baskets around. Some baskets might end up near the supernova. Others won't. And if you have enough warning, you can move those smaller craft out of the way quicker than you could move a planet. For example, given 10,000 years warning, you could move a significant distance away, while the planet just has to tough it out.

                        • (Score: 2) by Immerman on Tuesday July 07 2020, @02:36PM (5 children)

                          by Immerman (3985) on Tuesday July 07 2020, @02:36PM (#1017655)

                          >And how could I be thinking of redundancy on an individual basis?
                          The Earth is massively redundant as an individual system, because every ecological component is massively redundant.

                          >You don't need the full thickness of a planet to shield against such high energy events.
                          True, but you need a LOT more material than you would need to shield against normal background radiation in space, and it's extremely unlikely you'd apply that to all those artificial habitats since it's a massive disadvantage in all other circumstances.

                          >And one of the advantages of lots of slightly more fragile baskets is that you can spread the baskets around. Some baskets might end up near the supernova. Others won't. And if you have enough warning, you can move those smaller craft out of the way quicker than you could move a planet. For example, given 10,000 years warning, you could move a significant distance away, while the planet just has to tough it out.

                          There's no getting out of the way of a supernova, not within a solar system. Either you're got enough light-years of distance between you, or you don't. And the Earth is no more difficult to move than an equivalent mass of artificial habitats. And you're not going to get a whole lot of warning, since the radiation wave travels at light speed. With enough advancements in stellar physics we might be able to accurately predict the collapse 10,000 years out, but it seems a stretch since all the really interesting changes are hidden beneath thousands of miles of stellar material.

                          Assuming you do get millenia, or even decades of warning, the habitats could either try to flee, or just pile on a bunch more radiation shielding and hope for the best (probably far more reliable and cost-effective). Meanwhile the Earth will in fact tough it out - killing most life on one side of the planet is rough but easily repopulated within a few decades, especially if there's some human intervention. Assuming most human habitats were self-contained underground vaults (every bit as comfy as a space habitat, with far more radiation and impact shielding) we'd barely even notice except when visiting the parks on the surface.

                          • (Score: 1) by khallow on Tuesday July 07 2020, @11:29PM (4 children)

                            by khallow (3766) Subscriber Badge on Tuesday July 07 2020, @11:29PM (#1017919) Journal

                            The Earth is massively redundant as an individual system, because every ecological component is massively redundant.

                            So if I wipe out all life on Earth, some ecological component(s) will somehow do something to reverse that? I can do massively redundant ecological components with that other stuff too.

                            • (Score: 2) by Immerman on Wednesday July 08 2020, @01:35PM (3 children)

                              by Immerman (3985) on Wednesday July 08 2020, @01:35PM (#1018186)

                              Obviously not. But things are so massively redundant that you'll find it virtually impossible to wipe out all life on Earth, while wiping out all life in an orbital habitat would be trivial. And there's several common cosmic disasters that could wipe out all life in ALL such habitats in the solar system, unless they were ridiculously overbuilt to defend against such dangers that are unlikely to occur within any given million-year window. Disasters that the Earth *has* been repeatedly subjected to without jeopardizing the long-term survival of the life here.

                              • (Score: 1) by khallow on Sunday July 12 2020, @05:20AM (2 children)

                                by khallow (3766) Subscriber Badge on Sunday July 12 2020, @05:20AM (#1019737) Journal

                                while wiping out all life in an orbital habitat would be trivial.

                                What happens when the orbital habitat is bigger in land area than Earth, better shielded, and easier to move around because it's orders of magnitude lighter? I'm not saying this is the ideal way to do orbital habitats, but you have a lot of options with them and how they're configured that you don't have with a planet.

                                • (Score: 2) by Immerman on Sunday July 12 2020, @03:06PM

                                  by Immerman (3985) on Sunday July 12 2020, @03:06PM (#1019849)

                                  >What happens when the orbital habitat is bigger in land area than Earth...

                                  Then we've basically already ascended to demigodhood, can easily mine the gas giants, and probably even mine the sun directly for mass that we can transmute into whatever elements we want. So what's the motive for pulverizing Earth?

                                  One thing to keep in mind is that the asteroid belt already has enough material to build enough orbital habitats to support a thousand times the current population - and adding the other rocky planets would increase that by a few thousandfold more.

                                  Using just the asteroids we'll have a thousand times as many Einsteins, Mozarts, etc., and the pace of social and technological change is likely to be so high that the world (and what is possible) will be completely unrecognizable within a single generation.

                                  Meanwhile, if we assume 4 kids per woman to double the population every generation, it's going to take ten or fifteen generations to fill the habitats made from the dead rocky planets, with the number of active geniuses increasing all the time. I feel safe in assuming that we'd have advanced to mining the gas giants before kicking everyone off Earth began looking remotely appealing. And by the time we're done with the gas giants,mining the sun itself will probably be within easy reach. I suspect Earth will be spared by simple virtue of there being enough more attractive stepping stones that we'll blow right past having much industrial use for it

                                  There's a counterpoint as well though that I think may stop us from ever reaching such massive populations in the first place - social changes cause stress, which tends to reduce birth rates. Since larger populations cause faster social change, it seems likely that at some point the stress from the pace of social change will drive population growth below zero and stabilize the population. And frankly, it seems very possible we're approaching that level already.

                                • (Score: 2) by Immerman on Sunday July 12 2020, @03:33PM

                                  by Immerman (3985) on Sunday July 12 2020, @03:33PM (#1019861)

                                  Oh, and another thought on artificial habitats versus planets: Planets are held together by gravity - created by entropy, while artificial habitats will have to fight entropy constantly, mechanically holding themselves together against the pressure and centrifugal forces they contain. That means you need to constantly inspect and repair them, ideally through some form of integrated nano- or bio-technology, but for the foreseeable future you'd probably have to either overbuild the things enough that every single structural component can be replaced "live", or plan on retiring them periodically before catastrophic failure inevitably occurs. (I'd love to believe the first would be the norm, but we seem to have a real aversion to paying a substantial preium today for something that will benefit our grandkids.)

    • (Score: 2) by PiMuNu on Friday July 03 2020, @09:02AM

      by PiMuNu (3823) on Friday July 03 2020, @09:02AM (#1015703)

      Thanks, I searched arxiv, I didn't know about eartharxiv...

  • (Score: 3, Insightful) by zocalo on Thursday July 02 2020, @05:09PM (12 children)

    by zocalo (302) on Thursday July 02 2020, @05:09PM (#1015449)
    I read it as the structures are deep in the crust, but the ores themselves are much closer to the surface. They'd have to be, for us to be able to reach them; we've done much deeper bores, but the deepest mines in the world to date [wikipedia.org], mostly gold mines in South Africa, are all less than 4km down. This might be interesting news to mining companies, but it must be *fascinating* to geologists and planetologists, because if there's a connection over that distance then that's got to have some pretty big implications for both fields.
    --
    UNIX? They're not even circumcised! Savages!
    • (Score: 3, Interesting) by canopic jug on Thursday July 02 2020, @05:20PM (11 children)

      by canopic jug (3949) Subscriber Badge on Thursday July 02 2020, @05:20PM (#1015453) Journal

      And iron and various metals are mined at less than 1km or 2km. Even rich ore veins are not cost effective to mine deeper down than that. The cost of bringing the ore to the surface becomes more prohibitive as the mines go further down. For the most part they'd rather go sideways than down. If mines are running into economic trouble at 2km, they're really not likely to be profitable in most ways at 150km and deeper, at least not with current methods and mining technologies. Those would be too deep to be even remotely profitable to raise to the surface for now.

      Asteroids and their mining products, on the other hand, can be rolled downhill if they can ever be reached.

      --
      Money is not free speech. Elections should not be auctions.
      • (Score: 1) by fustakrakich on Thursday July 02 2020, @05:33PM (10 children)

        by fustakrakich (6150) on Thursday July 02 2020, @05:33PM (#1015459) Journal

        Well, I guess we just have to develop new technologies, the horror!

        And besides the process should be fully mechanized, you turn the machine on, and up comes your cobalt or whatever,, so costs aren't really an issue.

        --
        La politica e i criminali sono la stessa cosa..
        • (Score: 2) by Freeman on Thursday July 02 2020, @06:17PM (4 children)

          by Freeman (732) on Thursday July 02 2020, @06:17PM (#1015472) Journal

          Machines break, and there's going to be a lot of breaking when trying to mine something 100km below the ground.

          --
          Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
          • (Score: 2, Interesting) by fustakrakich on Thursday July 02 2020, @06:27PM

            by fustakrakich (6150) on Thursday July 02 2020, @06:27PM (#1015477) Journal

            And we can build machine that repair themselves, or they can resurface to be repaired by humans. It's still closer than the asteroid belt.

            With mechanization, scarcity is a thing of the past

            --
            La politica e i criminali sono la stessa cosa..
          • (Score: 3, Insightful) by ElizabethGreene on Friday July 03 2020, @04:06AM (2 children)

            by ElizabethGreene (6748) Subscriber Badge on Friday July 03 2020, @04:06AM (#1015670) Journal

            The trouble is the temperature. 1500F is a nontrivial materials science problem. That's the temperature where you forge iron, and it's difficult even for tungsten carbide in a nonreducing environment.

            • (Score: 1) by khallow on Sunday July 05 2020, @03:24AM (1 child)

              by khallow (3766) Subscriber Badge on Sunday July 05 2020, @03:24AM (#1016366) Journal

              The trouble is the temperature. 1500F is a nontrivial materials science problem.

              Then make it cooler. There's limits to how much heat you could dump on the surface of Earth (generating useful power in the process), but it's pretty high.

              • (Score: 2) by Immerman on Wednesday July 08 2020, @01:43PM

                by Immerman (3985) on Wednesday July 08 2020, @01:43PM (#1018192)

                Easier said than done. The challenge is not where do you dump the heat - it's how do you move massive amounts of heat tens to hundreds of miles, fast enough to keep the bit from overheating. The scale of the problem is akin to dropping a fine wire into a scalding hot tub, while keeping the water around the wire frozen.

        • (Score: 2) by HiThere on Thursday July 02 2020, @08:32PM (4 children)

          by HiThere (866) Subscriber Badge on Thursday July 02 2020, @08:32PM (#1015517) Journal

          Costs are ALWAYS an issue. If there are no material costs, then there are time costs. (And I don't really see "no material costs" ever happening.)

          Much easier would be greatly improved recycling, and probably even mining the waters of the ocean.

          --
          Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
          • (Score: 1) by fustakrakich on Thursday July 02 2020, @11:58PM (3 children)

            by fustakrakich (6150) on Thursday July 02 2020, @11:58PM (#1015594) Journal

            Time doesn't matter to the machine doing the work. It just has to produce as fast as we consume.

            --
            La politica e i criminali sono la stessa cosa..
            • (Score: 3, Insightful) by shortscreen on Friday July 03 2020, @02:10AM (2 children)

              by shortscreen (2252) on Friday July 03 2020, @02:10AM (#1015628) Journal

              It also needs energy. The premise of TFS was something about building infrastructure for renewable power. If it takes more energy to produce the materials to make the power plant than what the plant itself can produce during its lifetime then it becomes yet another boondoggle.

              • (Score: 1) by fustakrakich on Friday July 03 2020, @02:44AM

                by fustakrakich (6150) on Friday July 03 2020, @02:44AM (#1015646) Journal

                It also needs energy.

                Plenty of that everywhere you look

                --
                La politica e i criminali sono la stessa cosa..
              • (Score: 1) by khallow on Sunday July 05 2020, @03:32AM

                by khallow (3766) Subscriber Badge on Sunday July 05 2020, @03:32AM (#1016369) Journal

                It also needs energy.

                There's huge temperature differentials between the surface and 100 km down. The mining part may well pay for itself energy-wise.