Saturday, October 9, 2010

Mine Repair

A popular kind of mining these days is strip mining. When coal is to be found beneath a mountain, the easiest way to get the coal is to remove the mountain, and grab the coal. Unfortunately, this is also the worst for the environment, since both the mountain and where the rock is put generally gets completely destroyed. So federal law, and numerous state laws, require mining companies to repair and reclaim the land after the mining is done. After all, few people wish to live by a massive hole in the ground that will collapse the instant a heavy rain occurs. Mining companies have techniques to fill in the holes, plant grass, and leave the site looking similar to how it looked before, albeit now somewhat flatter.
I want to take my own stab at it. I think we need to fill the lowest level with rock, then we can have a small landfill layer (that we can fill with garbage or whatever), covered by a thick slab of cement. On the cement we have a thick layer of (finished) compost that reaches the surface. In the compost, we plant many many trees. After a few years of care, the trees grow into a mighty forest, which will stabilize the local environment. Areas in which the trees do not survive should be tested for things that may have killed them off, and to find a treatment plan. Can grass be grown instead in those areas? Or, are there chemical problems requiring treatment?
I think that geological research can establish a procedure cheap enough for the mining company, safe and stable enough for the land quality and environment, and accurate enough to be done over and over and over.

5 comments:

The Chinese guy said...

You are incredibly optimistic! I grew up near an open cast mine and the hole was gigantic. In 2009 I went past a gigantic mine near Tynda (Siberia) the hole was so big those massive massive dump trucks looked like ants in the distance. How on earth you could ever repair and or conceal this hole is beyond me... well you know what I mean, technically it is possible but the $$$$ involved would make the US debt look like pocket change.

Say how would an engineering solution fix this?

http://www.popgive.com/2008/03/darvaza-burning-gates.html

A hole in the ground has been burning since the 1970s, some smart so and so found a 'pocket of gas' and decided to burn the gas off 40 years later its still on fire.

Mad Engineering said...

There's a place in America that has a massive underground fire that will continue to burn for another 50 - 100 years, because someone was a moron. An entire town was evacuated. Incident #1 in this incident described by Cracked.
The average American strip mine requires, to refill the ruined land left over afterwards, a metric insane number of trucks. Imagine Hong Kong, with all its buildings removed, and covered in trucks, all filled to capacity with fresh soil and rocks. About that many. The only reason that it doesn't bankrupt the mining company is that they can do it over the course of five or ten years (and can refill the same truck a gajillion times.)
It's what I love about engineering: persistent megalomania.

Now as for the burning natural gas hole in Turkmenistan, the article says that the whole was deliberately set on fire to prevent the gas leak from poisoning the entire country to death. I suppose alternatively, you could have built a massive sealed dome over it and extracted the gas, but that's expensive.

Mad Engineering said...

Also, I'm not a professional engineer of any kind. I think I mentioned that in the first post, if it's even accessible anymore. The describing of insane projects is a hobby.
My major in college was computer science. I'm a programmer and system administrator.

TCG said...

Oh I know you're not a engineer by trade I'm just curious as to how you would stop a massive burning hole in the desert in the middle of nowhere and stop the leak. A dome seems far too conventional though! A nuke might seal it up nicely though.

Mad Engineering said...

The fire was their answer to "massive gas-leaking hole." The dome is a slightly crazier solution, because it allows you to actually keep the very useful gas. (Although it costs so much more that it's not worth it, hence the fire.)
Nuclear weapons would only leave the site radioactive for the next seven days. Not a good idea.

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