Federal investigators: Mine operator could have prevented explosion that killed 29 men

Massey Energy has since been acquired by Alpha Natural Resources.

The explosion occurred after a piece of machinery cutting sandstone ignited methane in the mine. That then spread to highly flammable coal dust, MSHA said in its presentation.

Massey Energy failed to adequately control the coal dust and did not provide adequate water sprays, the presentation said, adding that the company put an “emphasis on productivity to the detriment of safety.”

The company even pressured its employees to alter safety reports to make it appear that its mine were safe, according to Bloomberg.

MSHA is slated to release its final report on the disaster later in the year. The state of West Virginia has yet to release the results of its investigation.

Massey Energy, for its part, has maintained that it is not at fault for the explosion, arguing that it was caused by a surge in “methane-rich natural gas” that was out of the company’s control.

More than a year after the disaster, efforts in Congress to improve mine safety have sputtered, despite efforts by Rep. George Miller (D-Calif.), Sen. Jay RockefellerJohn (Jay) Davison RockefellerOvernight Tech: Trump nominates Dem to FCC | Facebook pulls suspected baseball gunman's pages | Uber board member resigns after sexist comment Trump nominates former FCC Dem for another term Obama to preserve torture report in presidential papers MORE (D-W.Va.) and others to pass legislation that would overhaul oversight of the industry.

Republicans say the Democratic reforms are too tough on the coal industry and threaten vital jobs in corners of the country already struggling with high unemployment.