CHARLESTON, W.Va. -- When the U.S. Mine Safety and Health Administration in February 2011 proposed a major rewrite of its "pattern of violations" rule, the agency said it should review the safety records of every mine in the country at least twice a year. Reviewing safety histories once a year -- as was the rule at the time -- "would not adequately allow the agency to identify mines with recurring" violations that warranted tougher enforcement action, MSHA said in its proposal. But earlier this year, when MSHA finalized its rule, agency officials backed off. The final rule, which took effect in March, requires MSHA to review mine safety records for potential "pattern of violations," of POV, actions only once per year. In explaining its action, MSHA said there was nothing to stop the agency from doing more than the one required annual review. "Under the final rule, the agency could conduct more than one review a year if conditions warrant, as it has done under the existing rule," MSHA explained in a Federal Register notice outlining its decision. Now, though, MSHA chief Joe Main is refusing to say how often his agency will conduct POV reviews. During an interview last week, Main said he wants the industry to remain in the dark about how frequently - and when -- MSHA might act. "Under the regulation, we are obligated to do one POV screening and action a year," Main said. "No one should ever take for granted that that is the maximum that will be exercised." "And no one should ever know at what point in time MSHA plans on implementing the POV rule," Main said. "I think the mystery in this is going to help folks understand that they should not be complacent, expecting that will be the only time the agency does this." Main made his comments last week, when MSHA issued its first POV notices under the new rule. MSHA cited three coal mines, including two in West Virginia, putting them on POV status, which means every additional serious violation issue prompts an order temporarily closing that part of the mine in question. One of the mines cited was Metinvest's Affinity Mine in Raleigh County, where two workers died in separate incidents on Feb. 7 and Feb. 19. The others were Patriot Coal's Brody Mine No. 1 in Boone County, and Tram Energy's Mine No. 1 in Floyd County, Ky. The notices are the latest in a renewed effort to use a program that lawmakers created in 1977, after finding that repeated citations by inspectors weren't enough to prevent a series of explosions that killed 23 miners and three inspectors at the Scotia Mine in Kentucky in March 1976. Under the POV program, mines with a history of safety problems are kicked into a tougher enforcement bracket. Each time an additional serious citation is issued, that part of the mine is closed. Mines can have the pattern-of-violations designation lifted only if they go an entire quarterly inspection without a series violation. But MSHA for years delayed in writing rules to implement the POV program. When it did write rules, critics say they had far too many loopholes. And screening of mine operators to look for repeat violators was sporadic. Officials from Patriot Coal and Metinvest, the two companies with West Virginia mines on the new POV list, both criticized the MSHA action and said they have already taken significant steps to improve safety at the operations in question. And various industry groups and coal companies are challenging the MSHA rule in court. They're especially upset about changes that eliminated a preliminary warning letter to mine operators at risk of being put on POV status and a move that allows MSHA to count citations and orders toward a mine's violation history even if those enforcement actions remain under appeal by the company. Gary Broadbent, a spokesman for Murray Energy, one of the companies that filed a legal challenge, said the MSHA rule "absolutely deprives coal operators of their right to due process, fails to protect coal miners, and is clearly unconstitutional." "We look forward to arguing our petition and getting this rule vacated," Broadbent said Friday. The court challenges are pending before the 6th U.S. Circuit Court of Appeals. Reach Ken Ward Jr. at email@example.com or 304-348-1702.