The market size is small, hence most trades are delayed 1 hour, bigger ones 2 hours.
There was quite alot of 'hot money' in prior to the drill rns, and i think with the actual rns being very good in numbers, was 'toned down' in style. I would guess that along with most of my resource stocks this week, a few punters are selling up for Xmas, i presume to come back after the new year.
As PNG is VERY illiquid, the market makers jump on any trade, in this case, i assume a couple of sells went through.