A jury in West Virginia found Don Blankenship, the former chief executive officer of Massey Energy, guilty of one of three charges he faced in relation to the explosion at the Upper Big Branch Mine in 2010 that killed 29 men.
The jury deliberated for two weeks before finding Blankenship guilty of conspiring to violate safety standards at the Upper Big Branch Mine, the site of the deadliest mining accident in the United States in 40 years.
Blankenship was found not guilty of making false statements and of securities fraud through lying about safety practices.
One of Blankenship's lawyers, Bill Taylor, told reporters the defense team was disappointed by the misdemeanor conviction but doubted Blankenship would serve any time in prison. Sentencing was set for March 23, Reuters reported.
Blankenship, 65, faces a maximum $250,000 fine and up to a year in prison.
U.S. Attorney Booth Goodwin told reporters he was not disappointed with the verdict. "It brings justice that is long overdue," he said.
U.S. Secretary of Labor Thomas E. Perez said, “Today’s verdict sends a clear message that no mine operator is above the law, that there must be accountability when people lose their lives because of the neglect of their employer."
The jury had deliberated more than two weeks and had twice told Judge Irene Berger it was deadlocked. Blankenship's lawyers did not present a single witness.
The jury began its deliberations on the afternoon of Nov. 17 — and the case seemed headed toward a mistrial after just one full day of deliberations, when the jurors sent a note to the judge on Nov. 19 saying they couldn't agree on a verdict and asking how long they should continue to try.
The defense moved for a mistrial at that point, but Judge Berger rejected the motion. A similar motion was also rejected by Berger two weeks after the first one.
The authorities say Blankenship, 65, closely managed the Upper Big Branch Mine, which was linked to hundreds of safety violations.
Assistant U.S. Attorney Steve Ruby said the core of the case dealt with violation of mine safety laws.
"It is a misdemeanor but a critical part of justice is accountability. The fact we were able to obtain that kind of justice today is a great victory," he said.
The conviction becomes the centerpiece of a wide-spanning investigation into Massey that began after the explosion. The probe produced four other convictions up the Massey corporate chain, leading to Blankenship.
Massey Energy was bought in 2011 by Alpha Natural Resources Inc. for about $7 billion.