CHARLESTON, W.Va. -- U.S. Sen. Jay Rockefeller is pressing the Obama administration to stop repeated delays of new regulations aimed at ending black lung and to move forward with other key coal-mine safety initiatives.In a letter to President Obama, the West Virginia Democrat said he is "extremely disappointed" that "rules designed to protect the health and safety of our nation's coal miners appear to again be delayed."Rockefeller's letter, dated today, focuses on the long-delayed proposal by the U.S. Mine Safety and Health Administration to toughen the legal limits for exposure to coal dust that causes black lung. The letter notes that two other MSHA initiatives -- both designed to prevent miners from being crushed by underground equipment -- have also been pending since 2010."I urge you in the strongest possible terms to direct your administration to move forward as expeditiously as possible on all of these issues, and to reaffirm your administration's commitment to protect the health and safety of our nation's coal miners," Rockefeller said in the letter.The letter noted National Institute for Occupational Safety and Health reports that warned of a resurgence of black lung, and autopsies that found miners who died in the Upper Big Branch Mine Disaster also suffered from the disease."This disease is back and will not go away unless we make it a priority and act," Rockefeller wrote.In recent weeks, West Virginia political leaders have resumed their harsh criticism of the Obama administration's policies related to coal's impact on the environment. Publicly, few of those state political leaders ever mention the repeated delay by MSHA of several key mine safety and health rules that are generally opposed by the coal industry.Rockefeller's letter was directed to the president, with a copy sent to Joe Main, who is assistant labor secretary in charge of MSHA.Also copied on the letter was West Virginia native Sylvia Mathews Burwell, who in April was confirmed as director of the White House Office of Management and Budget and must sign off on any new government regulations. At least one of the rules Rockefeller mentioned in his letter, a proposal for "proximity detection" systems on mobile underground mining equipment, has been pending at OMB for nearly two years.Rockefeller's letter to Obama comes less than a week after the senator introduced new legislation that would, among other things, force MSHA to within six months finalize its tougher limits on coal-dust exposure.MSHA proposed those limits in October 2010, but has yet to finalize the rule.Last month, MSHA pushed back its timeline for the final rule from a missed target date of June 2013 to September 2013. However, MSHA has yet to forward its final draft to OMB, where economic reviews of such matters can take many more months.Rockefeller noted that a December 2011 Republican budget rider delayed the MSHA rule until a U.S. Government Accountability Office report on the issue was completed in August 2012."It has been nearly a year since the GAO issued their report, in which it confirmed MSHA used key scientific findings to develop the aforementioned rule," Rockefeller wrote. "Despite this affirmation by the GAO, the rule has not yet moved forward."Black lung, or coal workers' pneumoconiosis, is an irreversible and potentially deadly disease caused by exposure to coal dust.One goal of the 1969 federal coal-mine safety law was to eliminate black lung. Deaths declined for years, but experts have been warning since the 1990s that the dust limits need to be tightened. More recently, since 2003, researchers have been documenting an alarming increased incidence of the disease in younger miners, whose entire careers took place under the 1969 law's dust limits.Last year, a joint investigation by NPR and the Center for Public Integrity, with additional reporting by The Charleston Gazette, documented widespread industry cheating on coal-dust controls and repeated inaction by regulators to try to end the disease.Between 1996 and 2005, nearly 10,000 coal miners nationwide died of black lung, according to the National Institute for Occupational Safety and Health. West Virginia recorded the second-highest black lung deaths of any state, with more than 1,800 during that period, according to NIOSH."No miner should have to face the destructive effects of black lung," Rockefeller said in his letter. "We must act now before we lose more West Virginia coal miners to this disease."The two other MSHA initiatives mentioned by Rockefeller focused on proposals to require mine operators to install proximity detection devices that shut off underground equipment when miners get too close to the equipment.One rule would cover adding such devices to continuous mining machines. Between 1984 and 2010, 30 miners died and 220 were injured nationwide when they became crushed, pinned or struck by these machines.MSHA proposed that rule in August 2011 and the public comment period closed in late November 2011. MSHA has yet to send a final draft of the rule to OMB for White House approval.The other rule would require proximity detectors on other types of mobile underground equipment. MSHA sent a draft of that rule to OMB in September 2011, but the White House has yet to approve it being proposed for public comment.Reach Ken Ward Jr. at email@example.com or 304-348-1702.