Is striated asteroid mining realistically feasible?

I have considered realistic asteroid mining as a means to attract additional funding for space technology. Would it be possible to use shaped explosive charges (nuclear even?) to blast loosely bond asteroids into a striated column (the lighter particles being blown farther away). By predicting the striation, it should be possible to mine the most valuable components whilst ignoring the rest, correct? This is similar to the biological science process known as electrophoresis (theoretically).