The acid shortage was real and it seems to me there were probably much larger consumers ahead of Excelsior in line.
Don't forget that the acid is critical to the entire operation. Other miners can continue to stockpile ore and start/stop the process much easier. The acid is critical to the entire operation with in situ. Given the problems they've already had starting wells and the likely lengthy period to get "push/pull" going, risking running out of acid, losing whats in the ground, and ramping back up is the last thing you want.
That being said I will be extremely dissappointed if we don't get an update in the next two weeks as to how far they've progressed with the initial wells that are pumping.