CHARLESTON, W.Va. -- Federal regulators said Wednesday they had blocked Massey Energy from using air scrubbers in dozens of underground mines because the equipment was not protecting miners from exposure to illegal levels of coal dust that causes black lung disease.U.S. Mine Safety and Health Administration officials also said they believe the real reason Massey is upset about the move is that it stops the company from taking larger cuts of coal, reducing the coal giant's production rates."We've taken away extended cuts," said MSHA coal administrator Kevin Stricklin. "That's the heart of the issue in my opinion."Extended cuts can allow coal operators to take up to twice as much coal, with cuts into the coal seam of up to 40 feet deep instead of 20 feet, Stricklin said.In an interview, Stricklin responded to Massey news releases that have attacked MSHA for shutting down the use of scrubbers on 62 of 132 continuous mining machines at Massey operations across the coalfields.Sticklin said MSHA data for last year show Massey had about 12 percent of the nation's mining units, but accounted for 23 percent of the federal citations issued for excessive dust in underground mines."That's telling me they're not doing very well in dust controls," he said.Stricklin said MSHA inspectors and Massey's own sampling showed violations of federal dust limits, even when the company's mines were using the dust-scrubbing machines touted by Massey.Massey has been pushing the scrubber issue in the wake of the deaths of 29 workers in an explosion at the company's Upper Big Branch Mine in Raleigh County. Massey has also complained that MSHA required ventilation changes at Upper Big Branch that reduced the fresh-air flow in that mine prior to the April 5 disaster.On the scrubber issue, Massey has issued two news releases this week, including one on Wednesday that called for MSHA to reverse its action and "take immediate and concrete steps to make the issue of scrubbers an immediate priority for the sake of miners' health."Among other things, Massey complained that MSHA "has never provided a written justification for their practice of turning off scrubbers" in underground mines."Our coal miners are also confused and, quite frankly, distressed by MSHA's action," the company said. "They cannot understand why the agency that has been created to protect their health and safety is doing the opposite."But MSHA issued a policy letter nearly two years ago, in June 2008, which outlined its plans for dealing with proposals for extended cuts and the use of continuous mining machine scrubbers.The two issues are related because other typical methods of ventilating the working mine face without scrubbers reduce the size of the coal cut that MSHA will allow.In its June 2008 policy, MSHA warned that, while scrubbers can be beneficial, the equipment must be properly operated and maintained."When a supplemental system such as a dust scrubber or spray fan fails to perform as designed and/or stated in the approved plan, the extended cut is no longer considered adequately ventilated," the MSHA policy said. "For mining to continue, the operator must revert to a previously approved standard cut plan that does not require the supplemental system to be functional."A month after that policy was issued, National Mining Association vice president Bruce Watzman wrote to Stricklin to object to it. Watzman argued that MSHA was moving with too broad a policy and that "scrubber use alone or in conjunction with other engineering controls or equipment represents an enormous technological step forward in methane and dust control.""If the agency's concern is that scrubbers are not being properly operated or maintained, these concerns should be addressed by enforcement of proper operation and maintenance -- not by an attempt to prohibit these highly effective and proven devices," Watzman wrote in a July 2008 letter.Reach Ken Ward Jr. at firstname.lastname@example.org or 304-348-1702.