Therein lies the reason that information must be released in a timely fashion. As a military communications person, I can tell you that the more information you have, the harder it is to keep a lid on it. In the military, we have ways of dealing with that, as does the business world, although they are different. Until 1996, military treason still carried a maximum punishment of death. The market is slightly more forgiving.
Getting back on track now, the point is that withholding information from the investing market creates the risk of a leak. In this case, if one of the majors Vale, Norilsk, Tech or Xstrata were to get wind of the assay results that are waiting for release (use your imagination to figure out how), they could feel confident in delivering a take-over bid of $12. Given the current price, that would allow for a double of the SP. Not sure what the shareholder protection plan is, but it might not be enough to matter.
As sag4tag said, the information is probably not in fact being horded, but is just slowly coming from the labs. I also agree that the information should be released in a manner that makes sense. Releasing assay results hole by hole is not the way to go, and so we wait.