"PO and BG already have voting power sufficient to 'go private."

It appears so, but I'm not sure that the SEC permits an insider takeover without a vote.  Logically, super shares can not be used for that purpose when designed to thwart an attempted outsider takeover.  However, I recognize that you likely know more about such things than I do, so please take a second look at this.

"But not sure why they would want to delist.  Would make selling shares over time a lot harder."

Not if there is substantive progress on the exploration front.  If so, the company can be relisted, with insiders pocketing fortunes before and perhaps after drilling.