On 12/8/26 08:49, Ian Whitchurch - ian.whitchurch at gmail.com (via tml
list) wrote:
> Basic grades of cheap steel is about a thousand a ton in the US, but
> the ingredients for steel are more like sixty a ton for the iron ore
> and ten to twenty a ton for the other stuff (which varies depending on
> which grade of steel). Good iron ore, that has a 60% grade you can
> shovel direct into a TL6 refinery, exists because of an active
> biosystem back in the neoproterozoic. Kind of ok iron ore, that has a
> 30% grade that you need to spend time and effort improving, is
> literally all over the place.
>
> If you handwave geology so that asteroid mining is sensible (briefly,
> ore concentration happens by active volcanic systems, active weather
> systems and active biosystems. These things don't happen in the
> asteroid belt, so either you had a planet that had those things happen
> that was then shattered by some War of the Ancients or other, or
> you're going to get a lot of boring, looks-about-the-same asteroids,
> or you're going to handwave geology because asteroid mining is cool),
> it's still got to compete with on-planet mining.
>
> The main plus asteroid mining has is that it is already happening in
> space, where the stuff that needs it is being made, with a secondary
> plus of not affecting anyone's view or ecosystem when you go about
> digging up the landscape.
>
> I'd suggest that the asteroid mine makes a lot of low value
> nickel-iron steel that's best used in space (oribting fortress to
> provide security against raiders !)rather than trucked back to the
> homeworld to compete with locally produced steel, a smaller amount of
> Valuable Stuff (real world niobium is about fifty grand a ton and
> makes expensive high strength steels) that is exported to more
> developed worlds, and a small amount of Really Valuable Stuff
> (gemstones ! Lanthanum !) that make an excellent maguffin.
>
> The mine makes it's money from the Valuable Stuff and the Really
> Valuable Stuff, and has a whole bunch of useful but low value
> nickel-iron steel thats already in space.
>
Regarding (asteroid) mining, I somewhat handwaved it in Parental
Advisory, as it was in the background, but I still wanted an economic
explanation for asteroid mining.

For ore-forming minerals, dirtside mining would, in general still
economically dominate asteroid mining.  The example I used for this was
Prometheus, a garden world with significantly richer mineral deposits
than Terra, 2 pc away.

For non-ore-forming minerals, the situation flips, and asteroid mining
tends to dominate dirtside mining.  Cheap, abundant energy for
processing (fission/fusion power) is readily available, with fewer
environmental concerns than dirtside.

Rare earth elements, since Ian mentioned lanthanum, are misnamed - they
are simply far less likely to form ores when subjected to the same ore
genesis processes.  For example, lanthanum (used for such trivial
gubbins as jump drives) is, per
https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth's_crust ,
over 2x as abundant in Terra's crust as lead is.

Ian's suggestion for local use of the nickel-iron makes perfect sense,
given Ewan's explanation of the background.

Alex