United Mine Workers of America spokesman Phil Smith told ILN the event was set for 10am local time May 21 at Keiner Plaza in St Louis.

On the podium will be union officials, former AFL-CIO secretary-treasurer Barbara Easterling, Missouri state representatives Jeff Roorda and Carla May, and St Louis Metro Central Labor Council president Bob Soutier.

The union did not indicate how many members and supporters it expected to attend.

The Missouri city is home to the headquarters of Peabody Energy, Patriot Coal and Arch Coal.

The demonstrations have been held more regularly over the past several weeks, in conjunction with the advancement of the Chapter 11 bankruptcy hearings of Patriot Coal in US Bankruptcy Court.

Judge Kathy Surratt-States is set to rule on May 29 regarding a motion by Patriot to make cuts that would effectively eliminate health care benefits for about 23,000 retired miners and dependents, including UMWA members.

“Let's call this what it really is,” UMWA president Cecil Roberts said.

“Corporate executives schemed to line their own pockets at the expense of sick, retired miners who did the labor that made them rich in the first place.

“We are advocating for the best possible result for our members before the US Bankruptcy Court … but this fight won't end when the judge rules.

“We've got additional litigation underway in West Virginia. We've got a bill in Congress which will hold the original employers of these workers accountable and we will continue to follow these companies and these corporate executives wherever they go.”

Patriot Coal, which was spun-off from Peabody Energy in 2007 and acquired Arch spin-off company Magnum Coal in 2008, filed for Chapter 11 last July.