Jeff Gentner / AP

Emergency vehicles leave the entrance to Massey Energy's Upper Big Branch Coal Mine in April 2010 in Montcoal, W.Va. after an explosion at the underground coal mine.

The owner of a West Virginia coal mine where an explosion killed 29 men will pay nearly $210 million in a historic settlement arising from the worst U.S. coal mining disaster in decades.

U.S. Attorney Booth Goodwin announced the settlement Tuesday, calling it a "revolutionary resolution" that is the largest of a criminal investigation into a U.S. mine disaster.

As part of the agreement, Alpha Natural Resources will not be charged with crimes but individuals still could face criminal prosecution. Alpha acquired Massey Energy after the explosion at Upper Big Branch.

The agreement includes more than $46 million in criminal restitution to the miners' families and $35 million in penalties for all Massey violations, including $11 million for Upper Big Branch. Another $128 million will fund cutting-edge mine safety upgrades.

Among the improvements will be digital equipment to monitor air flow and the presence of explosive methane and coal dust, reported the Charleston Gazette.

"We think that these requirements set a new standard for what can and should be in place to protect coal miners," Goodwin told the Gazette.

Alpha will also create a $48 million trust for mine safety research at academic institutions, the Gazette reported.

News of the settlement came hours before the U.S. Mine Safety and Health Administration was expected to release its findings into the April 2010 mine explosion.

The MSHA report will be the third report on the disaster, and echoes previous findings by an independent investigator and safety experts with the United Mine Workers, according to the Gazette. All three investigations conclude a spark ignited methane gas and a massive accumulation of explosive coal dust. Malfunctioning water sprayers allowed what could have been a small flare-up to become an epic blast that traveled seven miles of underground corridors, doubling back on itself and killing the men instantly.

MSHA will share its findings in a press conference scheduled for 3 p.m. ET.

• Slideshow: 2010 mine blast in West Virginia

The Associated Press contributed to this report.