I won't say it can't be done, but there are significant challenges here that you may be underestimating. Not the least of which is the fact that there is no "suck" orbit.
You need quite a bit of energy to make the proper orbital adjustments to aim the rock at a precise spot on earth (rather than some random ocean, somewhere inaccessible, a major city...) and lumps of asteroid aren't exactly known for being aerodynamic, making reentry calculations pretty unreasonable.
As long as you're cutting it, you could make it somewhat aerodynamic. However, you have to remember a lot of the time you want reentry vehicles (or rocks) to be round so that they get down in good condition.
In addition, you don't need to just fire it off into earth; you can attach a computer and small rockets to it so it can subtly and cheaply correct its own course. The energy you would need for this can be arbitrarily small: http://en.wikipedia.org/wiki/Edward_Belbruno
So what you do is, you break off small chunks and aim them--get ready for this--at Earth. A small meteor does not do real harm, and there are tons of them burning up in the atmosphere all the time. In addition, because you chose a high-metal asteroid, it'll get to the surface largely intact--rockier asteroids break up faster than iron-nickel asteroids.
Then, when it's on Earth, you recover it--maybe dredge it, if you sunk the rock--and separate and refine it.