It’s a very interesting concept, but with two notable exceptions, I don’t see how deep space mining becomes even remotely economically feasible in the foreseeable future. The fixed costs of a lunar mining operation would be staggering. As for asteroid mining...even the closest of the “Near Earth” asteroids are 100 million+ kilometers out.
That said, there *are* two cases where I can see a workable scenario coming to pass:
First, the discovery of plentiful amounts of extremely rare earths (yttrium, etc.) or other very expensive, useful metals (platinum, as another poster mentioned). Even if the method of obtaining them wasn’t ultimately cost-effective, just having access to those materials would have significant security and technological benefits. Kind of a stretch, but maybe.
The other scenario I can foresee working out would be the development of concurrent market demand by research interests. Say NASA wants to build that moon base after all. A mining interest could conceivably produce metals and other materials locally for less than the cost of shipping them up from Earth - certainly in less time, as the rocket power needed to carry a base worth of materials to the moon is itself a staggering number.
You need spacecraft that can return large payloads to earth. If we’re talking bulk metals I don’t believe the technology exists to land a payload like that?
But I am thinking of some possibiities. I guess you could crash small meteorites into dessert areas and re-mine from there. Or fly back with finished goods. Or just use the stuff in space.
It doesn’t make sense to send ‘anything’ from Earth (except people, and money).
The first space gazillionaire will be the man who lands on the moon with fuel to get back to NEO, 20 pounds of aluminum foil, sheet plastic, seeds, and a few hundred pounds of other stuff; secures the opening to a protected cavern on the pole with plastic, constructs a reflector and sets about producing food.
Exchange the food, and maybe the byproduct oxygen, to the space station(s) for fuel and waste products and sundries at less cost than sending it up from Earth.
There’ll be ‘tourists’ as soon as he’s ready for them.
And if I enter and win one of those huge lottery jackpots you can say you talked to that guy on the internet!