Tanked another 10 per cent on an up day, two or three weeks out...

Tanked another 10 per cent on an up day, two or three weeks out from a major resource upgrade. Any ideas as to what's happening with this stock?
It could be end of year tax losses, but that still wouldn't explain the dive in an up market.
The general lack of updates and information does obviously not help, especially from such an experienced management team. Volumes are thin, at least, but what is really disconcerting is that spectacular lack of interest from the market.