You might be interested in Planetary Resources [1]. They're planning to mine resources from asteroids though – no gravity well (like the moon) makes for easier transport from the source to the consumer.
It's very unlikely that SpaceX will be entering the space mining business. Musk doesn't seem to be a big fan of it, except in the context of mining resources on Mars for consumption on Mars.
SpaceX will certainly be interested in putting someone else's mining equipment in space though. If there is an asteroid gold rush, they're selling the tickets.
This is probably a better point. Established mining companies would be better off investing in research on how to extract raw materials once they are at the location.
Let another company (e.g. SpaceX) deal with the transportation. The level of specialisation at every steps is huge.
It's very unlikely that SpaceX will be entering the space mining business. Musk doesn't seem to be a big fan of it, except in the context of mining resources on Mars for consumption on Mars.
[1] http://planetaryresources.com/