The world's largest potash miners, whose control over output already exceeds that of OPEC over oil, are poised to tighten their grip on the industry even further. BHP Billiton's ( BHP:US ) $40 billion hostile bid for Canada's PotashCorp ( POT ) would combine BHP, which plans to produce 8 million tons a year of potash on its own, with the industry's biggest company, which can produce 12 million tons a year. In Russia, a merger between two major potash miners, Silvinit and Uralkali, is under negotiation as well.