Read the charging document here.Read more in the Coal Tattoo blog.CHARLESTON, W.Va. -- In a move up the Upper Big Branch Mine's management ladder, federal prosecutors on Wednesday charged a mine superintendent with conspiracy to violate mine safety laws and cover up dangerous conditions prior to the April 2010 explosion that killed 29 miners.U.S. Attorney Booth Goodwin alleges that Massey Energy mine superintendent Gary May plotted "with others known and unknown" to put coal production ahead of worker safety and conceal the resulting hazards on numerous occasions prior to the nation's worst coal-mining disaster in nearly 40 years."Today's charge is a significant step in the investigation of events at the Upper Big Branch mine," Goodwin said in a prepared statement. "Our investigation of those events remains ongoing."May, 43, of Bloomingrose, is accused of taking part in a scheme to provide advance warning of government inspections and then hide or correct violations before federal agents could make it into working sections of the sprawling Raleigh County mine.For example, prosecutors allege that May, after learning that federal Mine Safety and Health Administration inspectors were about to sample the level of coal dust in the mine, "surreptitiously redirected" additional fresh air to the area to conceal actual working conditions in the mine.Goodwin and Assistant U.S. Attorney Steve Ruby also allege that May "caused and ordered" the disabling of a methane monitor on a continuous mining machine at Upper Big Branch less than two months before the deadly blast.Also, May is alleged to have ordered an unnamed person to falsify mine examination records by omitting a hazardous condition -- high water that could endanger workers and interfere with the flow of fresh-air through underground tunnels -- required to be reported and then repaired.The charges against May were outlined in a 10-page legal filing known as an "information" rather than a grand jury indictment, a move that is usually an indication that the accused is cooperating with prosecutors and has or is expected to reach a plea agreement.May was charged not under the criminal provisions of the federal Mine Safety and Health Act. Instead, he is accused of taking part in a criminal conspiracy, which is an agreement by two or more people to violate the law. Specifically, he was charged with conspiring to defraud the federal government's mine safety enforcement efforts."The objects and purpose of the conspiracy were to hamper, hinder, impede, and obstruct the lawful government functions of the [Department of Labor] and MSHA in the administration and enforcement of mine health and safety laws at UBB," prosecutors said in the charging document.If convicted, May could face up to five years in prison for the one felony charge.Goodwin declined to confirm that prosecutors had reached a plea bargain with May, but said charging through an information "typically indicates that an agreement has been reached with the defendant and that's he's cooperating with the government's investigation.""This action represents the classic prosecutor's strategy: Compile evidence and testimony, then cut a deal with defendants to cooperate and provide further information leading higher in the organization," said Pat McGinley, a West Virginia University law professor who served on a team that conducted an independent probe of Upper Big Branch.McGinley added that, "The use of conspiracy law to pursue criminal law accountability represents a breakthrough of enormous proportions in deterring the types of outrageous conduct identified by UBB investigators."May's attorney, Tim Carrico of Charleston, did not immediately return a phone call Wednesday. Ted Pile, a spokesman for Alpha Natural Resources, which acquired Upper Big Branch in its June 2011 purchase of Massey Energy, did not respond to a request for comment.May was one of the mine superintendents at Upper Big Branch, having started at the operation in February 2008 as a mine foreman.At the time of the disaster, May was superintendent of the southern portions of the sprawling mine, which included areas being prepared for longwall coal production, but not the active longwall mining area where the explosion occurred.May was among the management employees at Upper Big Branch who asserted their Fifth Amendment rights and refused to answer questions from government investigators about the disaster.Just after the explosion, May was one of the mine managers who rushed underground and tried to rescue any survivors. But records show that investigators have also been told that May often ignored their concerns about safety problems, and sometimes only took action about such issues when he learned inspectors were headed underground.According to a management chart put together by MSHA investigators, May and another mine superintendent, Everett Hager, were on the fourth row down among Upper Big Branch officials. Above them were Performance Coal Co. President Chris Blanchard, Vice President Jamie Ferguson and general manager Wayne Persinger. Those officials were all below the level of corporate officers and executives at the Massey Energy parent company.The criminal investigation of the fire that killed two miners at Massey Energy's Aracoma Alma No. 1 Mine in 2006 never got above the section foreman level. The last prosecution of a mine superintendent was following the Southmountain disaster in Virginia in 1992.So far, May is the third person to be charged in the sprawling federal criminal investigation at Upper Big Branch.A former miner at the site was sentenced to 10 months in jail after he admitted to faking a foreman's license when he performed key mine safety examinations at the mine between January 2008 and August 2009 and to then lying to investigators about his actions.Next week, former Massey Energy security director Hughie Elbert Stover faces up to 25 years in prison when he is sentenced by U.S. District Judge Irene Berger after being convicted of lying to investigators and trying to destroy evidence about Massey's practice of warning underground workers of impending government inspections.In December, Goodwin and his team secured a $209.5 million settlement with Alpha Natural Resources, which acquired the Upper Big Branch Mine when it bought Massey Energy.Goodwin agreed not to prosecute the company for any Upper Big Branch criminal liabilities, but required Alpha to spend $80 million over the next two years on mine safety improvements and create a $48 million mine safety research trust fund. Alpha also agreed to pay $46.5 million in restitution to families of the disaster victims and $35 million to resolve pending Massey safety fines, including $10.8 million levied for violations related to the Upper Big Branch explosion.The settlement with Alpha, however, did not prohibit prosecutors from pursuing charges against any individuals -- including Massey officers, employees or agents -- who played a role in the mine disaster.Wednesday's charges were announced just one day before Thursday morning's planned release to Upper Big Branch families and the public of a report on the state Office of Miners Health, Safety and Training's investigation of the disaster.Shirley Whitt, whose brother Boone Payne died in the explosion, heard about the charges against May when a reporter called her for comment on them."I hope it's really the beginning," Whitt said. "I don't think May and Stover are where the problem was. It starts at the top. I want to see the people who caused this prosecuted."Reach Ken Ward Jr. at email@example.com or 304-348-1702.