By VICKI SMITHMORGANTOWN, W.Va. (AP) â¿¿ 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." The Mine Safety and Health Administration said the new rules could help prevent a disaster like Upper Big Branch. "This rule is long overdue, and it will, over the long term, serve to make mines safer for those who choose to be miners in this country," MSHA director Joe Main told The Associated Press. Among other things, the rules let MSHA designate a company a pattern violator without a prior warning. They also eliminate the requirement that MSHA can consider only final orders; previously, the agency could not impose the designation until the operators finished appealing violations, which could take months or years. Although MSHA has technically had the power to designate pattern violators since the passage of the federal Mine Safety and Health Act since 1977, Main said it didn't happen until 33 years later. "MSHA should not be prevented from taking action to protect the lives of miners for months, or even years, while we await the final outcome of citations and orders that a mine operator can easily contest," said Main, who took over the agency in October 2009. But the National Mining Association, which had objected to the rule when it was proposed in February 2011, said its concerns remain. It argues that because unsafe conditions must be fixed under current law, "no miner is put in harm's way if a citation is appealed."