"The actions we have taken ... are necessary for the survival of Patriot and the preservation of more than 4,000 jobs," Patriot president and chief executive Bennett Hatfield said last month.
"Our labor and retiree benefit costs have risen to levels that simply cannot be sustained given the challenges facing the company and our industry."
Union leaders say Patriot was "designed to fail" by Peabody and Arch. They say the companies spun off their hefty legacy costs to an undercapitalized company knowing it would never be able to sustain itself.
"They designed it to fail so that they could get rid of those liabilities," AFL-CIO president Richard Trumka told the Civic Center crowd.
In a statement, Peabody denied that claim.
"The UMWA's claim that Patriot Coal was 'designed to fail' is a desperate attempt to rewrite history," the company said.
The company said Patriot began as a successful company but suffered following its acquisition of Magnum and unforeseen events such as the global financial crisis and the national shift to low-cost natural gas for power generation.
Peabody officials say the company has fulfilled its requirements and should not be involved in the Patriot campaign.
"The UMWA is fully aware that this is a matter solely between the union and Patriot Coal, and the proper process for deciding such issues is through the bankruptcy court - not the court of public opinion," the company stated.
Trumka said the eyes of America were watching the crowd in Charleston. He said Patriot, Arch and Peabody's actions represented all that was wrong in corporate America.
"This is a story that America has heard too many times and we're sick of it and we're tired of it," he said.
"You can't be a 'Friend of Coal' unless you're a friend of coal miners," he said. "You want to call yourself a friend of coal, then get off your damn butt and stand with us."
Tomblin, Rahall, Manchin and Tennant all decried the decision to eliminate the promised benefits to retirees.
"Where I come from we have a saying: You can't shine crap - and this is crap," Manchin said. "You can't make it look good, you can't make it smell good, and you sure as hell can't make it taste good."
He and Rahall touted the proposed Coalfield Accountability and Retired Employee or CARE Act, a proposal they worked with Sen. Jay Rockefeller on that would require companies to maintain and fund retiree benefit plans.
"Those who are responsible will be held responsible under our legislation," Rahall said.