Get your resumes ready, they are now hiring.

http://www.planetaryresources.com/careers/

I'm thinking when I retire I'll volunteer to work for them for free,
if they have any need of my skills. I really want to see this get moving.

Regarding safety of cargo deliveries, I would say the best bet will be to limit
individual deliveries to a few tons, with a ceiling on package density. That way
failures will vaporize before impact. I'm also a bit sceptical of the idea of
brewing your own H2-O2 fuel/propellant from the asteroid water content. That may not
be at all a dependable supply, at least in the volumes required, and you have the
alternatives of solar sailing and solar powered rail gunning to do a large portion
of the return velocity, without depending on found fuel. Keep the water-fuel for
manoeuvring and braking. I guess that will need more R&D, so they're sticking with
what they know for now, but I am doubtful they'll find the quantities they need.

Regarding market depression, it will take years if not decades to
get the volumes moving to have that impact. I did a bit of checking
http://www.nss.org/settlement/asteroids/RoleOfNearEarthAsteroidsInLongTermPlatinumSupply.pdf
and it seems that terrestrial platinum sources are <1ppm platinum
(but it's so rare and valuable that's worth mining), whereas meteorite
(and thence presumably asteroids) are as much as 68ppm. That's still
a wee tiny amount, and a major amount of processing required, and sorting
out the other heavy metals (which are currently quite valuable, but less
useful, so far more vulnerable to price deflation), most of which will have
to be done here, I would think. I would guess they would be looking at
just a primary in situ processing - a quick cooking to concentrate the
good stuff and boil off the silica - solar powered, and definitely worth
it to get the return shipping weight down.

Anyway, where I'm going with this is that platinum is incredibly useful.
It is almost as inert as gold, has a very high melting point, which two combine
to making it desirable, in fact in some cases necessary, for use as containers
when cooking up high melting point substances. It also has all those well known
catalytic properties. As the price comes down, demand will go up markedly,
which will slow price deflation very quickly.

As to all the rest of those weird lanthanides, I don't know much about them
beyond that they're rare and heavy, but perhaps interest in them will result
in unexpected new uses. (They are rare because they are heavy, which means they
sank to the centre of the earth when it was molten, and we wouldn't have even
as much as we have now if it weren't for the Period of Heavy Bombardment, which
brought in a small amount on asteroids, which retain the primordial elemental
distribution, thus the expectation there'll be lots to find out there.)