MORGANTOWN, W.Va. -- A regulatory filing by Patriot Coal Corp. reveals that federal investigators have demanded information about methane gas detectors as they investigate questionable safety records at the Federal No. 2 mine in Northern West Virginia. The St. Louis-based coal operator said in a recent quarterly report to the Securities and Exchange Commission that the information was subpoenaed in late April. Investigators wanted information about what kind of gas-detecting equipment it has used at the mine near Fairview since July 2008. The subpoena also demanded the results of tests on that equipment. Patriot spokeswoman Janine Orf declined to comment on the 6-month-old investigation except to say the company is cooperating. John Renner, an ex-foreman from Granville who admitted faking a safety inspection report in January, is cooperating with the federal investigation and will be sentenced next year in U.S. District Court for making false statements and certifications. He faces up to five years in prison and a $10,000 fine. Though Renner recorded numbers for methane and oxygen levels on a sealed area in the mine, he later acknowledged he didn't do the inspection. Federal regulations have required seal monitoring because of a January 2006 methane explosion in a sealed section of International Coal Group's Sago Mine that trapped and ultimately killed 12 men. The massive longwall operation at Federal No. 2 has more than 90 seals, but Renner told investigators only a handful routinely caused problems. Renner has since been fired, and two other employees were put on administrative leave. On Tuesday, Patriot named a new operations manager for Federal No. 2. Thomas H. "Pete" Simpson, a veteran with 35 years of experience in underground mining and management, will succeed Joseph B. "Blair" McGill, who is retiring in January. The company did not say where Simpson has previously worked, but Orf said he was hired from outside Patriot. The revelations about questionable safety inspections at Federal No. 2 came just months before the April 5 explosion that killed 29 men at the Upper Big Branch mine, a Massey Energy Co. operation in Southern West Virginia. Although the official cause of that blast has yet to be determined, investigators have said they suspect a combination of highly explosive methane and coal dust. The federal Mine Safety and Health Administration included Federal No. 2 among the 57 coal mines nationwide that it targeted in an inspection blitz after the Upper Big Branch explosion. Inspectors fanned out to look for problems at mines with bad track records or known risks, such as high levels of methane gas. By mid-August, MSHA inspectors had issued more than 400 citations for alleged violations at Federal -- a 66 percent increase over the same period last year. The number of more serious violations nearly tripled, from 58 in 2009 to 161 this year. So-called significant and substantial violations typically carry higher fines and raise greater concerns among regulators. But the industry is not experiencing a similar increase: MSHA records show the number of citations issued to underground coal mines nationally dipped to 46,017 through July, compared with 48,744 during the first seven months of 2009. AP writer Tim Huber contributed to this report from Charleston.