At this low SP they don't want to have heaps of cash lying...

At this low SP they don't want to have heaps of cash lying about, would be a big target on their back. IMO global nickel production is about to fall in a hole very shortly and prices will rebound. The large stockpile inventory is holding at the moment as loss making producers attempt to prop up their cash flow by selling as much as they can. Like the death throws of a whale. Can't go on forever.
Far better to keep it in the ground, if you can, for better times. By selling now you only devalue their reserve/resource. As stated by MCR they can go from zero to full production in quick time. This will give them a great advantage by years end. My only gripe is that they took so long to go to C&M. But it would be great if we all had the benefit of hindsight.