DXN's market update noted that they would conduct DXN-SYD1 site...

DXN's market update noted that they would conduct DXN-SYD1 site visits for key investors.  These were slated to take place on Feb 20 and 21.

Based on today's trade volume and the timing of these trades, I would say that one or some of these investors were pleased with their site visit and went through the necessary internal hurdles to acquire or purchase more stock.  

If it's one of the existing substantial shareholders, hopefully they have purchased or will continue to do so until at least 1% of existing stock on issue has been bought so we can see a change in substantial shareholder announcement, which will confirm the above views.

This should be a positive sign for those shareholders (which is the bulk of us) who are not privy to the information disclosed / obtained from a site visit.