SYDNEY (Dow Jones)--A derailment in the coal rail network linking mines in Queensland state's Bowen Basin to the port of Gladstone is unlikely to disrupt exports thanks to high stockpiles, the port authority said. The derailment on the Blackwater line has stopped coal movements since Tuesday, although government-owned Queensland Rail said diesel services would return on one line Thursday. Electric services would take longer to restore, as overhead power lines were damaged when 20 wagons of a QR coal train left the tracks 150 kilometers west of Rockhampton around 5:20am Tuesday local time. Gladstone is one of the world's top five coal export ports, handling more than 38 million metric tons of coal every year. A spokeswoman for Gladstone Ports Corporation said that existing inventory at the port should be more than enough to cover any shortfall. "We've got two million tons of stockpile on the ground so we're still going as normal," she said. An exact figure for how long the stockpile would last is hard to calculate but it should be enough to bridge the shortfall, she said. "If it was going to go on longer there would have been some problems but if we're moving one million tons a week you could say that stockpile would do for two weeks." The Blackwater line serves 15 mines, including ones operated by Xstrata Plc (XTA.LN) Rio Tinto Ltd. (RIO.AU), and BMA, the Mitsubishi-BHP Billiton Ltd. (BHP.AU) joint venture that is Australia's largest coal exporter. -By David Fickling, Dow Jones Newswires; +61 2 8272 4689; [email protected] (END) Dow Jones Newswires June 10, 2010 00:46 ET (04:46 GMT)