BHP Billiton has called off itÔÇÖs bid for rival mining company Rio Tinto after falling commodity prices and regulatory demands that it sell off assets has left the firm with more than just cold feet. ┬á The firm said the decision had come from the European Commission, which had been set to deliver a verdict in January on whether the two Anglo-Australian companies could merge, as the combination would create the largest merger in the history of the mining industry.