I've attended many PDACs while working as a geologist. It wasn't unusual to show your face a couple of times and then disappear. Work goes on and if you are running a major project on a thin staff (which they are) you can't park at PDAC for the whole week. Many of their big shareholders will want private face time with them, JV partners will want updates on what NOT is going to be doing on the properties, money men will be making their pitches, etc etc. PDAC is a very busy time for business and most of it is conducted in private. Then there is the day to day business of keeping there major project humming along.
So maybe there is something 'meaningful' about them being away but its more likely to be 'normal' business.
.... Been There