[meteorite-list] "I've been a miner for a heart of ....

From: Alan Rubin <aerubin_at_meteoritecentral.com>
Date: Sun, 7 Apr 2013 15:39:16 -0700
Message-ID: <F0F3D4511A1041CEB44D65BE51F555C4_at_igpp.ucla.edu>

As long as we're being serious, Jeff has zeroed in on the most valuable
property of asteroids -- water. Until and unless manufacturing occurs off
the Earth, it is unlikely that PGE mining of asteroids will be
cost-effective. But as humans again start exploring space beyond low Earth
orbit, water will be a highly valuable commodity. Capturing carbonaceous
asteroids that contain 8-12 wt.% water will enable manned missions, where to
some extent, astronauts could live off the land like old-time invading
armies. If we could also learn to eat asteroids and use them for fuel, that
would be a great energy savings -- much less mass would have to be lifted
off the Earth.
Alan


Alan Rubin
Institute of Geophysics and Planetary Physics
University of California
3845 Slichter Hall
603 Charles Young Dr. E
Los Angeles, CA 90095-1567
phone: 310-825-3202
e-mail: aerubin at ucla.edu
website: http://cosmochemists.igpp.ucla.edu/Rubin.html


----- Original Message -----
From: "Kevin Kichinka" <marsrox at gmail.com>
To: <meteorite-list at meteoritecentral.com>
Sent: Sunday, April 07, 2013 2:35 PM
Subject: [meteorite-list] "I've been a miner for a heart of ....


....platinum (with apologies to Neil Young).

Team Meteorite:

This 'string' regarding 'asteroid mining' has attracted the scholarly
attention of the Rubin's and Grossman's and seems worth tying into a
couple more knots.

I'm all thumbs though when tying knots, so subject to peer review
which I will cheerfully accept from my uber peers Rubin and Grossman
(as well as my everyday peers on this forum).....

..... here's some more facts and data dug from two mining company
websites, hopefully properly interpreted by me, the mini-peer :>)

************************************************************************

On Earth, typically ten tons of ore must be crushed and refined to
yield one oz of platinum or platinum group metals (pgm).

***********************************************************************

That fact informs me that an unsupervised process in a harsh
environment like found on an asteroid in space will have a lower
yield.

The main concept of all this discussion is that bulk rock has to be
processed for shipping in a small package.

Next up is an abridged description of the process of mining ore to
acquire platinum group metals(pgm), compiled/copied from two websites
of mining companies in Africa, probably the richest source of Earth's
pgm.


*Concentration

The ore is ground to liberate mineral particles. These are then
recovered in the form of a concentrate by froth flotation. The ore
mineralogy dictates both the fineness of grind required for liberation
and the ideal flotation conditions. Very fine particles are difficult
to recover, so two or even three milling and flotation stages may be
used to minimise losses caused by over-grinding.

There are minor differences in the details of the equipment and
operations employed.... processing a metallic concentrate rich in PGMs
is sometimes produced in addition to the flotation concentrate. This
concentrate can be sufficiently rich to by-pass the smelter and be
sent straight to base metal removal.

*Smelting

The concentrate is melted in an electric furnace. Large units with six
electrodes in line are used for smelting concentrates.Upon melting,
the concentrate separates into two layers. The upper layer is a
silicate/oxide slag which is tapped off and then either discarded or
returned to concentration. The lower layer is a sulphide motto which
is sent for converting.

The flotation-concentrate composition must be suitable for smelting.
Its rock mineral content should produce a fluid slag at the desired
temperature. At the same time, it must contain enough sulphides to
form a reasonable quantity of matter. To compensate for minor problems
with chemical composition, various fluxes are added. Typically, the
main addition is burnt lime or limestone but other materials such as
carbonaceous reductants, sulphides, oxides or silicates are used as
necessary.

*Base metal removal

Base metals are removed from the converter matte either by leaching or
by a combination of magnetic separation and leaching processes.
Problem elements such as selenium, arsenic and tellurium are also
removed. The concentrate which results is sent for further processing
into refined precious metals. Base metals are a valuable by-product of
PGM extraction. Their further refining by the various producers is
largely dictated by economies of scale.

Refining

Precious metals refining processes have developed considerably in
recent years. The older or ?classical? process involved first roasting
the PGM concentrate. This made the rhodium, iridium and ruthenium
insoluble in aqua regia. The platinum, palladium and gold were then
dissolved and separated by a series of sequential precipitations, The
remaining residue was then upgraded by pyro-metallurgical and leaching
processes before being separated into individual metals. Final
purification of all metals was by repeated dissolution and
precipitation.

Improved separation and refining procedures have become available for
all of the precious metals. These commonly involve operations such as
solvent extraction or ion exchange. They are being introduced either
to replace procedures in the classical process or as part of
completely new refining processes. Advantages such as improved
precious metals recovery, lower refining costs and shorter processing
times are being claimed.

********************************************************************************************

Additional notes:

The first step in the mining process uses explosives to break the
rock, then it is loaded onto conveyor belts and delivered to machines
to be crushed into fine particles.

The "froth flotation" mentioned during the concentration stage
consists of 'flotation separation' where finely ground pgm particles
adhere to air bubbles in an aeration tank where they float to the top
and are skimmed off.

"Ore from different areas of the same mine can have quite different
characteristics" which I presume to mean varying pmg concentrations
and varying ratios and types of associated base metals either of which
would call for a variable processing regime.

Today's Conclusion by this mini-peer - At this point in the
discussion, I remain skeptical of the economic viability of this
scheme. I have some expertise in 'mining' because I follow
precious/base metals and mining companies daily while trading equities
(my main 'job').

While the price of gold might seem high this year, the miners are not
enjoying higher share prices, in fact they are being crushed (that's a
pun). Why? They borrow a lot and/or dilute shareholders with
additional share offerings because it costs a lot to be a mining
company even before political risks (acquiring permits,
taxation/royalties/expropriations) are considered. It's a bad
business.

The 'low apples on the tree have been picked' and the remaining
resource metals are now either deeper in the ground or of lesser
concentrations. Coupled with higher energy, labor, and transport costs
from ever more remote regions, this means 'owning a gold mine' ain't
what it used to be.

The processes described in those two websites work well with gravity
and when power to create high temps, fuel to power machines, and water
for everything else is readily available.

Engineers like difficult problems so -

- hauling machinery millions of miles away or -

- setting up 3D fabricating machines (and you still need refined metal
to duplicate the machine you want to manufacture),

- then controlling rocks blown into small pieces in a weightless
environment,

- in an airless setting where O2 is needed for bubbles in a tank of
(yep) water (need to make that, too)

- so that your specific crushed rock particles float to the top when
in a weightless environment there is no 'top',

- to be concentrated, fluxed, separated, leached and refined,

- THEN freight the finished product home as 'foam balls of concentrate' to

- safely re-enter Earth's atmosphere 'somewhere' to be collected and
shipped for further refinement and sale on an ongoing basis from a
planetoid millions of miles away all without direct adult supervision,

- while accountants on Earth calculate the revenues and sales and
declare some risk-taker wise and wealthy....

...will make a lot of engineers ecstatic.

Did this first appear on April One?

Sure FOOLED me.

"I want to live,
I want to give
I've been a miner
for a heart of gold.
It's these expressions
I never give
That keep me searching
for a heart of gold
And I'm getting old.
Keeps me searching
for a heart of gold
And I'm getting old."


Kevin Kichinka
Rio del Oro, Santa Ana, Costa Rica
www.theartofcollectingmeteorites.com
'The Global Meteorite Price Report - 2013'
Marsrox at gmail.com
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Received on Sun 07 Apr 2013 06:39:16 PM PDT