Tick tock, tick tock.

With the May 22 deadline for BHP to make a third and final offer for Anglo American rapidly approaching, chief executive Mike Henry faces one of the biggest tests of his career: does he increase his $64.4 billion bid and try to bring Anglo’s board to the negotiating table, or does he walk away in the name of capital discipline, and risk letting a rare opportunity to add more copper to his portfolio slip away?