MORGANTOWN, W.Va. (AP) — New federal rules approved Thursday could help save lives at dangerous mines with a pattern of safety violations and put more responsibility on companies to find and fix hazards, the U.S. Department of Labor said.

The changes were first proposed less than a year after the Upper Big Branch mine exploded in April 2010, killing 29 men. It was the worst U.S. coal mine disaster in four decades, and Labor Secretary Hilda Solis said her agency has since undertaken “a serious and comprehensive evaluation of mine safety practices.”