A couple of years ago a meeting was convened at the Shootout - - about the salt that's north and west of Floating Island. The stuff that's mentioned in this thread. Attendees included racers, BLM, and maybe the railroad (at least they were mentioned a few times as if they had been in on some of the discussions, perhaps earlier).
At that time the idea of using that part of the salt was decided to be feasible if the railroad company were to give access. A road to it is needed, a RR crossing, and more -- but not completely out of reach with enough $$.
Whether or not it will ever happen, it has been pretty well-researched. If you're interested in more on this subject -- PM or email me and I'll see if I can find one (or more) of the folks that were at the meeting - so you can ask for yourself.