“The unfortunate reality is that Westmoreland Coal Company and its subsidiaries cannot survive as a going concern without material changes to the retiree medical benefits currently offered to union employees and retirees,” the letter states. “We will be filing for Chapter 11 protection shortly and we will have no choice but to address this pressing issue.”

The company did not respond to a call late Friday for comment on this story.

In a separate court filing, the United Mine Workers of America noted that Westmoreland has confused its various obligations to retirees. The company had attempted to negotiate with the union to eliminate “retiree benefits” going forward, lawyers allege in court documents. However, the union has no authority over some of the benefits that Westmoreland is obligated to pay into, lawyers argue.

Congress set up benefit funds for miners that companies involuntarily pay into via taxes. Those obligations, the lawyers say, are non-negotiable.

This disagreement is also noted in letters between the union and Westmoreland prior to bankruptcy.