"Why would they send drills back when they could pop a couple holes in each one in a way shorter time frame. 4 drills can do 10 KNOWN GOOD targets faster than 2 can it not?"

It could be that some of their promising regional targets aren't accessible until the muck and water over top of them freeze up. Again, don't forget what the terrain is like up there. They aren't drilling in some farmer's field :)