United Mine Workers of America and nine other union members were arrested Tuesday while protesting outside the St. Louis headquarters of Peabody Energy, one of the companies the union accuses of orchestrating business deals that bankrupted Patriot Coal.That Chapter 11 bankruptcy has jeopardized pension and health care benefits for some 10,000 retirees and another 10,000 dependents, mostly in West Virginia, Illinois, Indiana, Kentucky and Ohio.More than 750 current and former miners from those states and their families rallied outside the federal building in St. Louis, where a bankruptcy hearing was being held, before marching through the city streets to Peabody's building.Peabody issued a statement saying it has "lived up to its obligations and continues to do so."The dispute is "solely between the union and Patriot Coal," said senior vice president Vic Svec, "and the proper process for deciding such issues is through the bankruptcy court, not the court of public opinion."Patriot didn't immediately comment, but the union posted an hour-long video of the event online, with union president Cecil Roberts leading the crowd in repeatedly chanting "Unions!" as police lined the federal courthouse steps behind them.The battle to save families' benefits may not mean much to Wall Street, the UMWA says, but to active and retired miners, it may mean the difference between life and death."Millionaires and billionaires, when they die, they die with great dignity because they've got health care," Roberts shouted. "Our pensioners and our widowers are just as good, if not a whole hell of a lot better than these millionaires and billionaires."The union is suing Peabody and Arch Coal in southern West Virginia, claiming they set Patriot up to fail so it would have to shed the pension and health-care benefits. Peabody spun off Patriot in November 2007, and Patriot later acquired mines that Arch spun off into Magnum Coal.Patriot now argues the legacy costs it inherited are "unsustainable."The lawsuit in U.S. District Court in Charleston argues Arch and Peabody are still responsible for those benefits under the federal Employee Retirement and Income Securities Act. The UMWA contends the companies knew that the cyclical nature of the industry would inevitably lead to Patriot's inability to pay for those liabilities.It says 90 percent of the retirees that Patriot is responsible for never worked for Patriot; they worked for Peabody and Arch.All three coal companies are based in St. Louis.They "may be proud of the financial con-game they're playing on these retirees to get out of decades of promises and obligations," Roberts said in a statement after the protest. "But the truth is that this is a sickening display of corporate greed that has overstepped the boundaries of decency. In an America where there are few boundaries for corporations, that's saying something."As he led the massive crowd through the streets, they chanted, "Peabody promised! Peabody lied!"Peabody said Patriot was highly successful when it launched, "with significant assets, low debt levels and a market value that more than quadrupled in less than a year. Svec said it also had what trade publications called "the dream team of top management" and a positive assessment by analysts.Patriot's solvency was affected by other factors, Svec said, including a global financial crisis, drops in the prices for metallurgical coal, competition from cheap natural gas and federal environmental regulations that raised costs."The UMWA retirees in question all worked for companies that are part of Patriot Coal," he said, "and Patriot's launch only occurred after the UMWA and its leadership specifically signed off on the retiree benefit payment structure with which Patriot started as an independent company."A federal judge moved Patriot's case from New York City to St. Louis in November. An $802 million financing package is allowing Patriot to continue operating while it restructures.Roberts and the others sat down in the street in front of Peabody's headquarters. Police allowed them to hold hands and listen to both a prayer and a recording of "Amazing Grace" before ordering them to move or face arrest. Union spokesman Phil Smith said that the 10 were charged with obstructing traffic.It was a planned act of civil disobedience that Roberts had joked about moments earlier."If you have not been told to go to jail, do not go to jail," he told the crowd. "We got enough money to get me out. ... Well, we got enough money to get you all out, to tell the truth."But the fight to preserve benefits is no laughing matter, and the union vowed to continue. "There's gonna be 10 of us go to jail," Roberts said before the arrests. "That is the first 10, but it ain't the last 10."