An anonymous reader writes: Peabody Energy Corp filed for U.S. bankruptcy protection on Wednesday after a sharp drop in coal prices left it unable to service debt of $10.1 billion, much of it incurred for an expansion into Australia. As demand for metallurgical coal fell, particularly in China, Peabody's financial woes intensified. The company took a $700 million write-down on its Australian metallurgical coal assets last year. At home, the U.S. shale boom of the past few years made natural gas competitive with thermal coal, and the Obama administration's environmental regulations raised operational costs. Mr. Peabody's coal train might not be hauling away any more of paradise. Peabody, the world's biggest private-sector coal producer, said it expected its mines to continue to operate as usual and said its Australian assets were excluded from the bankruptcy. "This process enables us to strengthen liquidity and reduce debt, build upon the significant operational achievements we've made in recent years and lay the foundation for long-term stability and success in the future," Peabody Chief Executive Officer Glenn Kellow said in a statement.