Before each of the nation’s worst mining accidents in the past 15 years, federal regulators overlooked major violations of safety rules intended to protect miners, according to a series of U.S. Mine Safety and Health Administration reports.Inspectors missed safety problems, did not take harsh enough enforcement action or ensure that problems were quickly fixed.Supervisors did not properly train inspectors or make MSHA requirements clear to them.Top agency managers did not do enough to ensure that far-flung district offices were doing a good job.“These deficiencies were found in both the district and headquarters level of MSHA,” said one report, which examined the agency’s actions at the William Station Mine in Kentucky in 1989.“Many involved oversights that can and should be readily corrected,” the team wrote. “Others are more fundamental and will require a commitment from the agency to resolve.”On Sept. 13, 1989, an explosion ripped through Pryo Mining Co.’s William Station Mine in Union County, Ky. Ten coal miners died.After the disaster, investigators found that federal mine inspectors repeatedly allowed Pryo Mining to overlook major safety problems. MSHA inspectors did not notice when company officials missed hazards during required pre-shift safety checks.MSHA officials promised that it would not happen again. They trained agency inspectors and supervisors to more closely review company pre-shift practices.A dozen years later, a series of explosions tore through the Jim Walter Resources No. 5 Mine outside Tuscaloosa, Ala. Thirteen miners died in the September 2001 disaster.After the accident, MSHA officials found that their own inspectors had again missed problems with the company’s safety checks.Hazardous conditions were not noted in pre-shift record books. Mine officials frequently listed hazards in a second set of books, without correcting them. Untrained miners routinely entered areas where pre-shift examinations had not been done.In the wake of the Jan. 2 disaster that claimed the lives of 12 miners at the Sago Mine, mine safety advocates and lawmakers are questioning how well MSHA ensured that safety rules were followed at the Upshur County operation.Pressure on the issue grew even more this weekend, as rescuers continued to fight a fire that killed two miners in the Aracoma Alma No. 1 Mine in Logan County.On Monday, MSHA officials and others will answer questions in the first of what is likely to be a series of congressional hearings on the Sago disaster.Sen. Robert C. Byrd, D-W.Va., has promised that the hearings will closely examine any potential failings on the part of MSHA.“The federal Mine Safety and Health Administration is supposed to be a coal miners’ shield,” Byrd said Saturday. “I worry that political decisions have weakened that shield. MSHA needs to remember that its mission is health and safety, and that mission must always come first.”Last week, MSHA announced that it had begun to assemble a team to conduct an internal review of its actions at the Sago Mine.Over the years, MSHA or its predecessor agencies have conducted internal reviews of their own enforcement actions after major mine accidents “to determine if there were lessons to be learned or if there were changes that needed to be made.”Generally, the results of these reviews have not been made public.In October 2003, for example, then-MSHA chief Dave Lauriski announced that “unexcused deficiencies” by agency inspectors were partly to blame for a June fatality at Cody Mining near McDowell, Ky. Lauriski declined to explain the nature of those deficiencies, and MSHA would not release records that might explain his comments.But on at least seven occasions, MSHA has formally published the results.Five of those seven accidents involved major mine explosions that killed 37 miners in four states. The other two involve an Arizona copper mine accident that killed four workers in August 1993 and the October 2000 coal-waste impoundment that spilled millions of gallon of slurry in Eastern Kentucky.In each of the explosions, special MSHA investigators found that the agency’s inspectors and managers had failed to ensure that coal companies properly performed the most basic safety checks: examinations required before every shift of miners goes to work.At the Fire Creek Inc. No. 1 Mine in McDowell County, two miners died in a Jan. 16, 1991, methane explosion. As part of its accident investigation, MSHA found that Fire Creek managers had not conducted pre-shift examinations.Six mine officials and Fire Creek Inc. pleaded guilty to criminal mine safety violations for falsifying safety records and failing to perform pre-shift examinations. In its internal review, a team of MSHA officials found that agency inspectors did not make sure Fire Creek was doing these examinations.During four of the five consecutive inspections before the explosion, MSHA inspectors did not arrive at Fire Creek before miners went underground. Therefore, the internal review found, MSHA inspectors “could not have determined whether pre-shift examinations had been made before the miners entered the active underground workings.”MSHA internal reviews also found a failure to ensure operators conducted pre-shift examinations before the William Station and Jim Walter disasters, and before the March 1992 explosion that killed four workers at Consol Energy’s Blacksville No. 1 Mine in Monongalia County and the December 1992 explosion that killed eight workers at Southmountain Coal Co.’s No. 3 Mine in Wise County, Va.In at least three of the explosions, MSHA reviews found that agency officials did not ensure that mine operators complied with mine ventilation plans and sought government approval before changing those plans.After some of the explosions, MSHA investigators found that accidents occurred at least in part because the agency failed to write safety rules that were required by Congress.At Blacksville No. 1, a Consol employee and three contractors died while sealing a mine shaft. The contractors had not received training for working near hazardous mining operations, such as methane-emitting shafts.But MSHA had not written rules to spell out the requirements for such training. When it passed the 1977 Federal Mine Safety Act, Congress required MSHA to write those regulations. Lawmakers did not provide a deadline for doing so.When it wrote some training rules in October 1978, MSHA exempted these types of contractors from training requirements. The agency said it would write rules for them later.“MSHA did not address this issue again as a regulatory matter until April 23, 1990,” the internal review of the Blacksville explosion said. MSHA added the contractor training to its regulatory agenda, but then dropped the proposal again in April 1991.In its review of agency actions surrounding the Martin County slurry impoundment, MSHA found that agency officials did not heed warnings of serious problems at the Massey Energy facility.The MSHA internal review found that top agency officials ignored staffers who recommended additional studies and safety precautions. Also, the internal review found that agency officials did not follow standard procedures when they reviewed plans for the impoundment.