I do not believe NOT intends any hotile take overs it is not in their best interest. Because int he world of hostile take overs there are alot of companies with way more money to take over NOT.

That said here is one way a company like NOT does a hostile take over if it wanted to.  Not could do a PP with a major say at $10 for ruffly %10 of NOT'S owner ship. This would inturn give NOT   some where in the neighbour hood of 133 million dollars in a war chest.  NOT in turn makes a hostile offer for PRB shares of let's say $5/share.  If NOT gets collective share holders selling out say 15milion shares for a cost of  $75 million NOT now owns the controlling vote of PRB and the rest would be history.

But as I stated in the beginning I do not think this kind of play is in NOT's best interest and therefore would not happen.