A former Massey Energy mine executive who admitted to conspiring in an illegal advance-warning scheme has been ordered to spend three-and-a-half years in prison.

David C. Hughart, 54, of Crab Orchard, was sentenced to 42 months in jail and three years of supervised release after he pleaded guilty to two federal charges as part of an ongoing federal probe of Massey’s safety practices.

Hughart admitted that he took part in a decade-long conspiracy to hide safety violations from federal safety inspectors.

U.S. District Judge Irene Berger ordered Hughart to serve a full year more than the high end of the 24- to 30-month recommended under advisory federal sentencing guidelines. The judge said the stiffer sentence was needed to account for the safety risks Hughart’s crimes created and to serve as a warning to other mining officials not to put production before safety, the Associated Press reported.

Hughart, a former president of ex-Massey subsidiary White Buck Coal Co., never worked at Upper Big Branch but is cooperating in a probe of the disaster.

He acknowledged he helped ensure miners at other Massey operations got illegal advance warning of surprise safety inspections, the Associated Press reported.

The Hughart sentencing is another step forward as U.S. Attorney Booth Goodwin and his top assistant, Steve Ruby, continue what is likely the largest criminal investigation of a coal-mine disaster in modern times.

The probe started with the deaths of 29 miners on April 5, 2010, in an explosion at Massey’s Upper Big Branch Mine, and has so far prompted four convictions and expanded well beyond Upper Big Branch.

“We are going to take this investigation wherever it leads,” Goodwin told reporters during a brief news conference on the lawn of Beckley’s federal courthouse. “I appreciate it has taken some time, but we have been working diligently. We think this is a significant step forward for our investigation and for the safety of the miners,” Goodwin said.

Hughart is cooperating with prosecutors, having pleaded guilty to one felony count of conspiracy to defraud the government by thwarting U.S. Mine Safety and Health Administration (MSHA) inspections and one misdemeanor count of conspiracy to violate MSHA standards, the Charleston Gazette reported.

During a plea hearing in February, Hughart had implicated former Massey CEO Don Blankenship in the conspiracy, and Hughart's family has said Hughart is being wrongly scapegoated while Blankenship and other top Massey executives have faced no criminal charges.

Through his lawyer, Blankenship has denied any wrongdoing. And on his blog, Blankenship has said Hughart lied about him and was fired from Massey for drug use and stealing from the company.

Prosecutors have said that former executives and board members of Massey “may be, or may become” targets in the ongoing federal criminal investigation.

Previously in the Upper Big Branch probe, a former miner at the operation, Thomas Harrah, 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 then lied to investigators about his actions.

Berger sentenced a former Upper Big Branch security director, Hughie Elbert Stover, to 36 months in jail after Stover was convicted of two felonies: making a false statement and obstructing the government probe of the mine disaster.

And in January, the judge sentenced former Upper Big Branch superintendent Gary May to 21 months in jail and a $20,000 fine after he pleaded guilty to plotting to skirt safety rules and cover up the resulting hazards.