In last week’s Proceedings of the National Academy of Sciences, researchers published a review of the rates of metals mining and use that presents an alarming possibility: for the first time since the onset of the Industrial Revolution we may face resource scarcity in the next few decades. This conclusion is alarming only in the sense of what it may do to global prices, but for those of us who advocate space resource utilization (particularly asteroid mining), this news has been expected for quite some time. Finally our civilization must face resource scarcity and it will need to look to space in order to continue to develop and grow.
Metal Scarcity
In their article “Metal Stocks and Sustainability” (citation at CiteULike.org), Gordon and others examine the history of the mining, use, disposal, and recycling of copper. The graph on the left summarizes their results quite well: the diamonds indicate cumulative copper discoveries, while the squares signify cumulative copper use. Sometime in the next few decades, we will have mined substantially all of the copper that the Earth has to offer. Never before have humans truly faced resource limitation like this (On a side note, I have begun reading “Beyond Oil : The View from Hubbert’s Peak” (Kenneth S. Deffeyes) about another kind of resource limitation. I will be posting about this book and about the issue in general soon).
Much of the copper we use can be recycled, but to satisfy world demand nearly 100% of the copper in use must be recycled. Recycling the bulk of copper is relatively cheap, but as the percentage increases, so does the cost. However, copper use is not slowly tapering off, instead it is steadily increasing. As nations such as China and India continue to industrialize, they will demand copper in ever increasing quantities. There is no way for current world copper supplies to provide the entire world with copper use per capita as high as that in the industrialized world.
The authors then examine a number of other “geochemically scarce minerals” including Zinc, Platinum group metals, Tin, Silver, and Nickel to see if similar scarcity issues have arisen there as well.
- Unlike most metals, most of the zinc that is mined is eventually lost to dissipative uses including metal plating and galvanizing, thus zinc supplies will be constantly declining. Zinc, like copper is not abundant enough to provide the entire world as it has the industrialized wester world.
- The Platinum group metals have long been used for jewelry, and more recently have found uses as chemical catalysts. In the US, every one of our cars uses platinum in our catalytic converters, and platinum group metals make the most efficient catalysts in current generation fuel cells. The authors estimate that 500 million fuel cell vehicles would be sustained for only 15 years with the Earth’s supply of platinum.
- Tin seems to be in plentiful supply for the foreseeable future, even with the increase in its use in lead-free solder in recent years. The world supplies are probably on the order of 100 times current annual use.
- Silver has a number of uses including jewelry and electronics (it is a component of lead-free solder as well), and is in far shorter supply globally than tin. The authors estimate that the world’s silver supply can continue to be met for approximately the next 50 years. Thus “silver appears not to have an imminent resource constraint.”
- Approximately 70% of the world’s nickel use goes into stainless-steel. The authors estimate that world nickel supplies are as much as 5 times what a fully industrialized world would require. Thus nickel appears not to be in short supply globally.
Asteroid Mining
So, it appears that both copper and the platinum group metals are in looming short supply. Can asteroids meet this demand? Asteroids come in three primary types, C, S, and M. The S (silicaceous) and M (metallic) types are of interest for near-term asteroid mining because M types are basically solid metallic iron and nickel, with a bit of cobalt and platinum group metals mixed in, while S types are rich in iron and other metals. The M types are thought to be remnants of the cores of larger planetoids that broke up in collisions, while the S types seem to be crustal remnants.
When planetary bodies form, the heat from their formation melts them and allows for planetoids of sufficient size to differentiate. Differentiation means that heavy elements sink to the core of the body while lighter elements remain on the surface. This is what happened on the Earth, which is why we have a metallic core. Since iron and nickel are nowhere near as heavy as some of the other metals, why don’t we have a lead and uranium core? Well, we do, kind of. But due to the nature of the iron and nickel nuclei, they are the last elements that are readily formed in the fusion in stellar cores. Heavier elements must all be formed in supernovae, thus they are far less abundant throughout the solar system. Likewise, metallic asteroids do possess copper, silver, gold, and all other such elements as well, though not in abundances anywhere near as large as those of their primary constituents.
| Perhaps the platinum group metals will be the catalyst (heh, heh) for profitable asteroid mining |
If I can venture into the realm of speculation a bit, asteroid prospecting will be an important endeavour because somewhere exists an asteroid rich in copper, and another in silver or gold. But even if a “typical” M- or S-type asteroid is mined, significant quantities of all these metals will accumulate. These rarer metals will be vital to continued development on Earth and may be used to subsidize the extraction of iron and nickel that are, for now, plentiful on Earth. These metals would then be used for space infrastructure development. The trade revenue earned from sending back rare metals could then be used to purchase value-added goods such as electronics and health supplies. Perhaps the platinum group metals will be the catalyst (heh, heh) for profitable asteroid mining, but once we’ve paid the price to develop infrastructure there, we might find it far cheaper to extract nearly pure metals in space and send them back home.
The Earth Needs Space
Regardless of space colonization and interplanetary trade considerations, we will need the resources that space has to offer. We will need its metals, its Helium-3, and most importantly, its solar energy. Increasing efficiency in metal use and recycling can hold off true scarcity, but at some point the demand for material will be more than exists on the Earth in an extractable form. Even with the ridiculously short timeframe of today’s politics, it won’t be long before no industrialized can afford to ignore the riches up there.
Asteroid mining seems to be coming at us from various directions. Certainly the shortages you discuss here will serve as an impetus, but we also have to learn to exploit the asteroids because we may someday have to nudge one out of an potential collision with Earth. That means an outer-system infrastructure that can handle industrial as well as basic security needs. It would be heartening if we saw a stronger commitment from NASA to the advanced propulsion technologies that will one day make this happen.
Paul,
You make a good point, the inevitability of asteroid redirection will make us a whole lot more familiar with asteroids when that time comes. I don’t know that advanced propulsion technologies will be necessary to move asteroids around. The gravitational tug method published last November makes asteroid redirection a very near-term reality.
Yes, there seem to be real possibilities with the gravitational tug. But those dangerous Earth-crossers from the outer Solar System (or, for that matter, a comet) would demand that we get to them a long way out, where a small nudge applied over a long period can work. That’s where the propulsion breakthroughs come in, I think — we have to be able to move large manned payloads into soem very distant places to set up the needed fix.
hey anthony,
longtime reader, firsttime poster.
Maybe its my Chinese bias, maybe its my propensity to talk about geeky things like moon mining while drinking with my fellow geek friends, but I’ve also heard about this moon energy mining initiative being a distant phase of the Chinese space program via slashdot . Seems like these days the best (if not only) way to really get people motivated to do anything is about energy, and this Chinese H3 idea, however hare brained it may be, might be even more compelling than mining metals. Do you know anything about this? I’ve had a tough time trying to track anything about it & am loathe to trust reporters anyway.
In other news, I got my brothers 17″ powerbook (he had to switch to PC for his major & was majorly angry about it). holy damn. its nice.
Ben,
You talk about moon mining with your geeky friends? Damn! When you were still around here all we talked about was politics and soccer
About the H3 mining, I do know a fair bit about it, and I’ve wrote about it a bit in an entry summarizing fusion energy research. The Chinese are in a position to soon dominate the world in technology and engineering-related science, energy included. Mostly this is because they think big, and their leaders can plan on decades-long timescales. I don’t know how credible the idea of Chinese H3 mining is, any more than the Russian proposals that I’ll mention in my next entry. But it’s not hard to believe that if any nation does the H3 thing, that it may very well be China.
Paul,
Good point about the Outer Solar System objects, I hadn’t thought about those as being distinct from the Inner SS Earth-crossers.
[…] Bill White makes the case that mining platinum group metals (PGM) from the lunar surface could provide a near-turn economic return, unlike He-3 mining. As I mentioned in my blog entry on metals scarcity, there may be a market for PGMs for fuel cells that could be very profitable for extraterrestrial mining. […]
In regard to living in space and the need to guard against excessive radiation, are there asteroids thought to contain lead, that, being such a heavy element, could be mined in the future to block it?
Indeed, does the ISS use lead to block radiation?