The nation's most dangerous mines should become safer under a new federal rule that allows regulators to identify operators who are chronic violators more quickly and force them to fix the most hazardous safety problems in their mines.

The rule, announced Thursday by Secretary of Labor Hilda L. Solis, strengthens the federal Mine Safety and Health Administration's ability to identify and declare a "pattern of violations" by a mine operator by allowing it to consider a broader range of enforcement problems.

"The rule ... will hold mine operators accountable when they disregard life-saving safety measures," Ms. Solis said.

"Generally speaking, this rule is a step in the right direction," said Phil Smith, a spokesman for the United Mine Workers union. "We think it will help improve miner safety."

Under provisions of the Federal Mine Safety and Health Act of 1977, MSHA is required to issue a "potential pattern of violations notice" and consider only final violation orders when deciding to issue a "pattern of violations notice" that would make a mine liable for enforcement actions and sanctions, including closure of portions of the mine.

But from 1977 through 2011, no mine was ever placed on "POV status," according to the Department of Labor.

That includes Massey Energy's Upper Big Branch Mine in Raleigh County, W.Va, where 29 miners were killed in April 2010 in a coal dust explosion. MSHA's final report on the accident in December 2011 concluded there were flagrant safety violations at the mine, issued 369 citations and fined the operator $10.8 million.

The Labor Department said it issued the new pattern of violations rule in an effort to prevent coal dust explosions like the one in the Upper Big Branch Mine. The rule is MSHA's third regulation in response to that explosion. Previously, the agency issued tighter dust control standards and required improved inspections in underground coal mines.

Joseph Main, assistant secretary of labor for mine safety and health, said the new rule will make declarations of pattern of violations status a more consistent and effective enforcement tool.

"There has been recognition by many that the system has been broken," Mr. Main said. "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. The new rule addresses those flaws."

Cecil-based Consol Energy, the largest underground coal mining company in the nation, declined to comment, saying it needed more time to review the rule.

• Former top executive at Upper Big Branch mine sentenced for conspiring to cover up mine accident.

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