New South Wales agreed to pay BHP Billiton A$220-million ($170-million) to buy back a coal exploration licence that extends under prime farmland in the state’s eastern Liverpool Plains, the government said on Thursday. “After careful consideration, the NSW Government has determined that coal mining under these highly fertile black soil plains… poses too great a risk for the future of this food-bowl and the underground water sources that support it,” Premier Mike Baird said in a release.