Lift the bottom end up in the air with a loader, take the top end apart and pull the flighting out.

You have to pull the flighting out anyway to fix the broke bolt issue.       If you want to pull all of the flighting out the top end you need to take the flighting loose at the bottom before you start.    

IMO, now is a good time to  pull all of the flighting out and put all new bolts in because you will very likely have more broken splice bolts soon if you don't.        I'm pretty sure the flighting is in 10' sections with bolts at every splice.     

Make sure to use good lock nuts when you put it back together.  If possible use a bolt length that has enough length so that the bolt shoulder is doing the work even if it means using a flat washer or two to get the bolt tight before running out of threads.