In reply to Egowling1:
I used Mc Nett Aquasure Shoe repair on my nepals. However mine were only seperating in 3/4 small places likley caused by wellying my boot into a crack. I worked it in with a pin then used cord and tape to wrap the sole.
If it has instantly failed i suspect its PU degredation of the mid sole, the repair is unlikley to be effective because the glue will stick the upper back to the mid sole and the degrading mid sole will just disintergrate bellow the glue surface.
Worth a try none the less, but perhaps have a backup plan if you are relying on them.