Given the nature of the general area play in the JBL and the so called 'Big Money' involved, I would conclude that the big asks on top of the SP is someone controling the assent of the share price for very specific purposes. Given PRB's location adjacent to and on direct strike line to the mineralization at DE I suspect someone is not allowing the SP to jump to reflect this fact. Compare PRB to the other (SouthEast - off strike line) and make your own conclusions.

Old Joe