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This is perhaps too soon, but I had read of asteroid mining a few weeks back. Do asteroids harbor these rare earths? The mining process seems pretty messy. I wonder if we could get minerals that way, there would be no need to do more damage to our environment.
It'll be a decade or more before asteroid mining goes anywhere. Probably decades even.

And mining this is not any messier than mining anything else.

Not all mining is the same.

Copper / Gold mines tend to be extraction of a concentrated deposit by either open pit or tunnel, while there are exceptions they tend to be limited in surface area affected.

Mineral sands mining for rare earths is often akin to strip mining for large broad area coal seams - very large areas are turned over just to access a thin layer - where mineral sands occur beneath old growth forest it's often the case that the entire forest would have to be removed, as opposed to a gold mine that might simply tunnel beneath.

Other techniques of note include uranium leach mines where a well head pumps fluid underground and other well heads extract dissolved salts, this leads to relatively small amounts of surface disturbance, and (for the hell of it) marine based alluvial diamond dredging - performed by barges across deposits from current or ancient river mouths. Again, not a lot of surface disruption.

The extraction of a billion dollar lead/zinc deposit two thirds of the way up a mountain in Greenland will be very different to any usual rare earth extraction.

Greenland Deposit :: http://www.youtube.com/watch?v=BvUol1aS8UA

In the long term we can hope for this. But simple logistics say it'll be decades at least before we on Earth will possible see benefit. Potentially only when the upper crust's resources start to draw thin will it really kick in, based on what I reckon about the prices of returning materials in bulk.
Everything is pretty much a tradeoff. Sucks to be near the mine but those minerals probably improve tech so much that eventually the environment is x times better off in a global scale.
I was curious if Rare Earths are really useful for the environment or mostly used in short-lived gadgets like MP3 players.

For anyone as clueless about the uses of Rare Earths as me, I liked the diagrams in this PDF.

http://www.oeko.de/oekodoc/1111/2011-002-en.pdf

They play a role as trace elements. A lot of these elements are blocking in nature: other parts of the organism's metabolism are a function of the availability of trace elements. As an example, Molybdenum was found to put a ceiling on CO2 uptake in certain Orchidaceae. So if you run an orchid nursery and want to reduce your IV-to-flower time by providing more CO2 you need to also provide adequate amounts of trace elements. You could compare it to adding Iodium to table salt in order to keep the population's fertility high.
I'm not sure that this comparison really answers anything about the parents question. In the case of organisms, these elements are needed for the organism to survive; not to make it more efficient/compact.
Most of the cost & risk of space exploration goes into the short trip from earth's surface to orbit. Getting free from surface is such a major factor that it actually makes sense to move launch to a location near the equator. Once you have extraction and processing in space, volume and mass no longer play a role in what you can do up there. That's where asteroid mining has potential: provide an infrastructure that mines and processes resources in situ. I don't think one can justify the cost of mining it in orbit and then bring it back to earth.
I work in mining so I'm greatful to have found this and read it.

It baffles me, however, how could this ever make it on hacker news?

Technology.

China currently has a massive grip on rare earth production, ergo a massive influence on the future of iPods & mobile widgets. Without alternative mines the bulk of technology production in the world that's centred about rare earth usage will migrate to China for the costs breaks ...

It's a fascinating complement to the "apple supply chain" articles that were making the front page a while back. None of the articles I read mentioned China's rare-earth mineral export policies as one of the factors that led to its virtual lock on electronics manufacturing - most of them rather characterized it as a snowball effect. If this was as important to the erosion of US manufacturing as it seems, this could be an important missing piece for hardware manufacturing (and its jobs) to come back to the States.

(Not that semiconductor manufacturing jobs are the kinds of "good" jobs we're so desperate to grow here, c.f. Karen Hossfeld's ethnographic study of the immigrant women who made up the bulk of silicon valley's manufacturing workforce)

Is there a chance to gradually replace these rare-earths by more common stuff?
No. rare-earths have very unusual properties not found in other elements.

BTW, don't let the name "rare-earth" confuse you - not all of them are actually rare, they are just called that.

One impediment has been heavy restrictions on thorium, which is a waste product of heavy rare earth mines. Some people are trying to get those restrictions modified, to allow both rare earth mining and development of thorium reactors.
Exciting to see some good news for California's economy!