In her 102-page ruling, Surratt-States concluded that Patriot's actions were legal and perhaps even unavoidable.
The UMWA said that more than 90 percent of the retirees whose health care is now at risk never worked a single day for Patriot. Rather, they spent their careers with Peabody or Arch Coal.
Union leaders say Peabody Energy and Arch Coal spun off assets and set up Patriot to fail in a deliberate plan to end benefit obligations to union retirees.
Patriot denies that, saying its bankruptcy results from the global financial crisis, tighter environmental regulations and a reduction in metallurgical coal prices.