Not in the short term see (http://en.wikipedia.org/wiki/Asteroid_mining#Financial_feasi...). It is a lot cheaper, easier and less risky to mine even very rare minerals on Earth rather than do so in space. And will be too for the foreseeable future. Plus any investor doesn't want to dump platinum on the market as then the price would plummet and seriously erase the profit. And you'll want a lot of guaranteed returns to undertake such a financially risky investment.

I could see Space Tourism taking off though. Taking space jet skis out for a spin round the moon and back that kind of thing. Perhaps some exclusive space hotel.