Double blow for Australia's mining industry as 900 jobs are cut "Although we are not breaking down the reductions by individual site, the restructure is focused on scaling back high cost production at some of our mines," it said. BHP Billiton, the world's biggest miner, said it will halt the open-cut Gregory coal mine it runs as a joint venture with Japan's Mitsubishi. Up to 297 jobs are set to go at the Queensland site. Like Xstrata, BHP cited falling prices, high costs and the strong Australian dollar as it announced the mine, running since 1979, would close from October 10. "Gregory open-cut mine production was no longer profitable in the current economic environment," it said, adding that the underground mine would stay open.