Someone's been playing too much Dwarf Fortress...

Im not to sure what I was on about back then, but I think I know what I was on about. I think I ment get the Liquid Nitrogen from compressed air, then filtering it to just get the pure nitrogen for the cooling. I did not mean underground. I believe the purified mantle material is to get rid of impurities in it so that we get suitable materials for bullet making. Really though, I screwed up massivly on the power supply issue, A better source of power whould be Geo-thermal, And a good position to place it whould be on a volcano.

If that phrase ever comes up with any kind of design other than something related to suicide, shoot the architect.

No, shoot the idiot who asked the architect to make it there. Architects have little control over the location of the thing.
Also...

Again, what? Pure mantle material is liquid rock, the impurities are exactly the things you need to make bullets. What you're thinking of is the Earth's core.

The execution pit?
A volcano would be a good place to put that.
Or maybe a city.
Also, isn't mantle mainly iron?

I know for sure the core is solid iron, and I'm pretty sure the mantle is mainly magma. Though I might have not been paying attention to the teacher, as usual.

I'm well aware of cities near volcanoes, My mum comes from near Legaspi and the Mayon Volcano. But living ON a volcano. I mean yeah, lets get a load of metals that are near impervious to destruction and really good insulation from heat and maybe we can hit this off, but until then I can't see this relationship going anywhere. I'm sorry Julie.

B-but... we had so much... ;_;
Would iron bullets work?
Also, I don't think magma is an element.

Of... course... not? What's the connection? It's just molten rock.

Alright, does anyone know what mantle is composed of?
Anyway, if all else fails you could just pump mantle onto approaching zombies.

Primarily oxygen (44%) with the next runner-up being magnesium (22%). Though the lower mantle is so far down that you'd need a month or two of continuous drilling to get there.

By that time, your drill would have melted anyway.

I Guess super-dense carbon nano-tubes whould not help... How about un-obtanium (Sneaky(If it was so sneaky I whould not have used Brackets) Reference to the movie Core)? Its ment to be to use pressure, to increase the strength of the material (Practically impossible).

The Core is an abomination unto science surpassed only by the argument "without darkness there can be no light" when used in a scientific sense. Thou shalt never speaketh of it again.

I also think the mantle has some nickel thrown in there.
Lets see what wikipedia has to say...
http://en.wikipedia.org/wiki/Mantle_(geology)#Characteristics