I wonder what minerals they expect to find that will make it economically worthwhile to recover and bring back. Right now, chemically pure and highly enriched fissionable material in pre-shaped, non-critical ingots or perhaps some easily fusionable isotopes, like Tritium, might make economic sense on a per kilogram basis, but not much else.

Of course, if there were already existing space colonies and bases that needed cheaper materials than could be hauled up out of the gravity well, then there might be a market for even simple and commonplace materials, like water or methane.

I've always fantasized that the asteroid belt might somehow have conditions that would allow the natural accumulation and easy harvesting of small amounts of monatomic hydrogen or even antimatter, but that is purely speculative.

There is other potential loot in that same vein. We might find alien artifacts out there. Living extraterrestrial microorganisms would be incredibly valuable, we could base entire alternate biochemisties on earth, and there may be possible chemical compounds that might form naturally in that environment that can't be duplicated on earth. If they have commercial applications, it might be real treasure. After all, who would have guessed Europeans would shell out good money for tobacco, tea, and chocolate.