The Financial Post reports in its Tuesday edition the prospect of new competition from miner BHP Billiton could dynamite the cracks appearing in a potash duopoly that accounts for 70 per cent of global trade in the fertilizer. A Reuters dispatch to the Post says for decades two export groups, Belarus Potash Company (BPC), which represents producers in Russia and Belarus, and Canpotex, its North American equivalent, have set identical prices in key markets such as China and India and have often curbed output simultaneously. That choreography, which smaller players also dance in step with, is already under fire; four producers in the groups -- BPC's Uralkali, and Canpotex's three members Potash Corp. of Saskatchewan, Agrium and Mosaic -- recently agreed to pay over $100-million (U.S.) to settle a U.S. antitrust lawsuit accusing them of concerted action to raise prices. BHP is also mulling whether to proceed with its eight-million-tonne-per-year Jansen mine in Saskatchewan, which would be the world's largest potash mine if it opens as scheduled in 2017. BHP, which has said it will not join Canpotex, would probably look to maximize volume sales to make sense of its $14-billion (U.S.) investment.