His father was an activist and leader with the United Mine Workers of America (UMWA), and Yablonski began to represent him.
Yablonski won a court order forcing the local coroner to perform an inquest.
This provided evidence that helped the families win expanded survivors' benefits from the Pennsylvania Workmen's Compensation Board.
"Jock" Yablonski, a long-time union representative, made a number of attempts to reform the United Mine Workers of America (UMWA).
In the 1980s, he won several black lung disease cases, overcoming employer objections to providing medical and financial benefits for stricken miners and their families.
He lost both times, and filed election fraud petitions with the United States Department of Labor (DOL).
Sadlowski then sued the union to recover his legal fees, incurred by Yablonski, Joseph Rauh and two others.
On December 16, 1981, the U.S. Supreme Court agreed that the union must cover the cost of legal fees up until the time Sadlowski filed his DOL fraud claim.
The clinic was founded in 1955 by UMWA to bring health care to mining families in rural areas of Pennsylvania.