Once the feature starts, only the reels that do not yet contain any gold continue spinning. You begin with three respins . Whenever new gold lands, the counter is immediately reset to three. If no new gold appears, the counter counts down.
That means the hunt continues as long as you keep adding to your collection. It only ends when all respins have been used up or all positions have been filled with gold. At the end, all collected values are added together and credited directly to your bank.