A motion by Patriot Coal to cut health benefits for 10,000 retired miners was heard Monday in a federal bankruptcy court in St. Louis.
More than 1,500 protesters, many with the United Mine Workers of America, rallied in downtown to draw attention to the case.
The UMWA is angry with Patriot for asking a federal bankruptcy judge to allow it to shed about $1.6 billion in liabilities.
But they also direct their anger at Peabody Energy, which spun off Patriot in 2007.